CANINES Flashcards

Question

A 5-year old male mixed breed dog presents with polyuria, polydipsia, polyphagia, and weight loss. The most likely diagnosis is \_\_\_\_\_\_. a. Exocrine pancreatic insufficiency b. Diabetes mellitus c. Hyperadrenocorticism d. Hypothyroidism

Answer 1

b. Diabetes mellitus ## Footnote Diabetes mellitus is the most likely diagnosis of those listed above. The 4 classic signs of DM are PU, PD, PP, and weight loss. EPI patients have PP and weight loss but are not PU and PD. Hyperadrenocorticism patients have PU, PD, and PP, but do not lose weight. None of the clinical signs described are consistent with hypothyroidism in a dog.

Answer 2

a. Weight gain leading to obesity ## Footnote Insulin deficiency causes weight loss, not weight gain. An insulin-deficient dog is essentially starving the cells of its body. Its energy utilization is impaired because it can't import glucose into its cells. In response to the decreased energy in the body's cells, the liver upregulates gluconeogenesis and glycogenolysis, exacerbating the hyperglycemia. The mobilization of fat is increased to supply the body with an alternative energy source. As adipocytes are broken down, the resulting free fatty acids are imported to the liver where they are converted to energy, triglycerides (which are stored in the liver causing hepatic lipidosis), and ketones (causing ketosis).

Answer 3

c. Correction of acidosis, electrolyte abnormalities, and hyperosmola ## Footnote Initial treatment of DKA patients is aimed at correcting acidosis by administering bicarbonate (if the total bicarbonate is markedly low), correcting electrolyte abnormalities with IV fluids, potassium and phosphorus supplementation, and correction of hyperosmolality. Regulating blood glucose, getting the animal to eat, controlling obesity and concurrent disease should be addressed after immediate life-threatening issues are resolved.

Answer 4

a. Central diabetes insipidus ## Footnote Diabetes mellitus is ruled out with a normal blood glucose on the chemistry panel and lack of glucose in the urine on the urinalysis. Chronic renal failure is ruled out because there is no azotemia on the chemistry panel. Fanconi syndrome usually occurs in Basenjis and is ruled out because there is no glucose in the urine.

Answer 5

c. Initiate therapy with cyclosporine ## Footnote The signalment, history and clinical signs are most consistent with a perianal fistula. Although the pathogenesis is not fully understood, this disease is thought to be primarily immune-mediated. The treatment of choice for perianal fistula is medical management with cyclosporine, as resolution is achieved in greater than 65% of dogs. Surgical correction may lead to fecal incontinence or stricture formation, however surgery for removal of the anal sacs in combination with cyclosporine has recently shown promise. If this was an anal gland abscess, lancing the abscess and drain placement with systemic antimicrobial therapy would be indicated. If you suspected this to be a cancerous process, a minimum database including CBC, chemistry, thoracic radiographs and abdominal ultrasound are recommended for disease staging. The treatment of choice for anal sac adenocarcinoma is surgical resection, followed by adjunct therapy.

Answer 6

b. Dopamine ## Footnote Adrenergic vasopressors are frequently used to treat hypotension during anesthesia. Drugs in this category are dopamine, dobutamine, ephedrine, phenylephrine, and norepinephrine. Atropine and glycopyrrolate are anticholinergic drugs. Hydralazine is a vasodilator used to treat hypertension.

Answer 7

b. Urethral stricture ## Footnote This puppy has a urethral stricture. There are no abnormalities involving the abdomen or urinary tract on the pre-contrast lateral radiograph. A contrast urethrogram was performed. A Foley catheter was placed in the distal urethra and the balloon inflated. Non-ionic contrast medium was injected, and several radiographs were taken during this procedure. There is a focal narrowing of the urethra 1cm caudal to the os penis. This narrowed area is visible on contrast projections. Urethral strictures may form secondary to trauma or lodged calculi. The normal urethral narrows through the pelvis, then widens slightly at the prostate gland. True narrowing or filling defects should be visible on multiple images. Air bubbles can mimic filling defects but will move to different locations in the urethra as contrast is injected

Answer 8

a. Confine the dog and observe it for 10 days ## Footnote With a healthy, vaccinated dog, the 10 day confinement period can be carried out in the owner's home. You would only need to euthanize and test if the dog is an unvaccinated stray. If the dog was not up-to-date on vaccinations, you would either euthanize and test or quarantine for 10 days in an approved facility. The answer choice to vaccinate the dog immediately and quarantine for 45 days would be recommended if the dog were bitten by an animal that was rabid or suspected to be rabid.

Answer 9

a. Sporptrichosis ## Footnote All of these fungal diseases can infect both animals and people. However, they are not considered contagious (not to be confused with infectious) with the exception of Sporothrix. This is because they are mainly acquired from the environment, and transmission from animal to animal is rare. Sporothrix, especially in cats, is a high risk to veterinarians and care should be taken to limit contact with exudates and lesions in cats. Aspergillus is generally considered a ubiquitous fungus that causes infection due to host factors such as immunosucceptibility or certain breed predilections. Cryptococcus is also not a contagious disease (do NOT confuse this with cryptosporidium, which is very contagious and zoonotic as several of my colleagues can attest to profusely). Cryptococcus infection occurs from inhalation of the yeast from the environment, frequently avian habitats, as it survives ideally in pigeon droppings. Essentially, histoplasma, blastomyces, and Coccidioides are also all environmental diseases as well and not considered contagious. Incidentally, there is a true story of a pathologist who did acquire Coccidioides from an animal that was having a necropsy. It is likely that the fungus reverted to the mycelial phase and produced infectious arthroconidia at the low temperatures achieved in the dead animal. This is also a risk when changing bandages for the same reason. These fungi are also potentially infectious when they are being grown on culture plates. So even though they are not technically contagious (at least in terms of how the board examiners view them), there are still risks.

Answer 10

c. Chloramphenicol ## Footnote Even though this is a human question, this is something you do need to know for board exams. This potential side effect of chloramphenicol is why it is not allowed for use in food animals and that it is used with caution in companion animals. The person administering this drug should take precautions to avoid coming into contact with it.

Answer 11

d. Baylisascaris ## Footnote Baylisascaris procyonis is an ascarid parasite of raccoons that causes mild signs in raccoons but can undergo aberrant migration in humans and cause fatal central nervous system signs.

Answer 12

b. Zinc ## Footnote Huskies are predisposed to zinc-responsive dermatosis in which individuals have a higher requirement for zinc in their diets due to a defect in abdorption of the element. Clinical signs include crusting and scaling of foot bads, elbows, eyes, and mucocutaneous junctions.

Answer 13

a. Pulmonary neoplasia ## Footnote Hypertrophic osteopathy is visible as periosteal proliferation in the diaphyses of affected bones. Usually the metacarpal and metatarsal bones are affected first, and it may progress to the long bones. Lameness, pain, and swelling are usually evident. Joints are unaffected. The cause is usually primary or metastatic pulmonary neoplasia, although other diseases in the thorax including bronchopneumonia, Spirocerca infection, or congestive heart failure, may also be associated. Less commonly, abdominal neoplasia may be seen with this lesion

Answer 14

b. It may take up to 3 days to overcome medullary washout from being polyuric and polydipsic ## Footnote DDAVP is a synthetic ADH used to replace the lacking endogenous hormone. DDAVP does not induce the hypothalamus to make ADH. Medullary washout commonly occurs with CDI from prolonged PU and PD\> It may take up 3 days to get the medullary sodium concentration and concentrating mechanisms back in order. ADH receptors in the kidneys are not affected in CDI.

Answer 15

d. Mirtazapine ## Footnote Although, all of the options given can potentially help a cat with renal disease feel better, the only medication considered an appetite stimulant is mirtazapine. Martazapine works by increasing norepinephrine in the system, which acts as an alpha-receptor agonist, causing an increase in appetitie. It is also a serotonin receptor antagonist, which inhibits 5HT2 and 5HT3 receptors, so it acts as an anti-emetic as well. Famotidine (Pepcid) is an H-2 receptor blocker while omeprazole (Prilosec) is a proton pump inhibitor. Both reduce gastric acid secretion. Maropitant (Cerenia) is a neurokinin-1 inhibitor, which inhibits Substance P in the CNS Metoclopramide is a prokinetic and anti-emetic drug. The mechanism for its anti-emetic effects is from antagonism of dopamine at its receptors in the chemo-receptor trigger zone of the brain.

Answer 16

d. A high-dose dexamethasone suppression test could help differentiate pituitary versus adrenal dependent hyperadrenocorticism ## Footnote The correct answer is you should run a high-dose dexamethasone suppression test. Elevated blood cortisol concentration 4 hours and 8 hours post low- dose dexamethasone administration is diagnostic for hyperadrenocorticism, but it does not allow differentiation between PDH and a cortisol secreting adrenal tumor. Dexamethasone is more rapidly metabolized in dogs with either type of hyperadrenocorticism (approximately 4 hours to metabolize as opposed to 30 hours in normal dogs). In PDH animals, the 4-hour post-cortisol concentration may sometimes be suppressed, whereas cortisol from adrenal tumors will not be suppressed after administration of a low dose dexamethasone. A high-dose dexamethasone test will suppress a larger percentage of PDH patients (up to 75% will be suppressed, showing a decrease in cortisol after 4 hours). Less reliable test to differentiate PDH from an adrenal tumor include endogenous plasma ACTH concentration or abdominal ultrasound.

Answer 17

c. It is important to limit calcium intake to prevent skeletal abnormalities ## Footnote In fast-growing, large-breed puppies, diets high in calcium have been shown to predispose them to osteochondrosis and retained cartilage cores.

Answer 18

a. Fenbendazole ## Footnote Trichuris vulpis is the canine whipworm. It commonly inhabits the cecum and causes diarrhea, weight loss, or hematochezia in severe infections. Light infections are subclinical. Treatment is with fenbendazole or milbemycin oxime.

Answer 19

c. Panhypoproteinemia ## Footnote Lymphagiectasia is a classic example of a protein-losing enteropathy. It is characterized by dilation and dysfunction of intestinal lymphatics and leakage of protein-rich lymph into the intestinal lumen. As a result, protein, cholesterol, and lymphocytes are all lost. Calcium is also frequently low due to either low albumin or vitamin D and calcium malabsorption

Answer 20

d. Vasopressin ## Footnote Epinephrine and phenylephrine are adrenergic vasoconstrictors. Isoproterenol and dobutamine cause vasodilation. Casopression (also known as anti-diuretic hormone) is a V-1 receptor, non-adrenergic, vasoconstrictor

Answer 21

b. Atrial fibrillation ## Footnote Although the rate is not fast, **there are no discernible P waves and the R-R interval varies with each beat. This irregularly irregular rhythm is a hallmark of atrial fibrillation**. Normal sinus rhythm and sinus arrhythmia are incorrect as there are no P waves apparent. Atrial premature complexes i wrong because the irregularity is from the fibrillation waves in the atria, not a discrete premature focus. Second degree heart block is not correct because no P waves are seen, as would be expected with intermittent block

Answer 22

a. 6mm/min ## Footnote A normal Schirmer tear test is considered to be greater than 15mm/min. A value between 10-15 mm/min is considwered marginal and may or may not be consistent with Keratoconjunctivitis Sicca (KCS), which is dry eye. When diagnosing KCS it is important to have a good clinical picture, especially when the Schirmer tear test is in the gray area.

Answer 23

d. Atipamezole ## Footnote Medetomidine is an alpha 2 agonist sedative/analgesic often used for premedication to general anesthesia, chemical restraint, and for epidural anesthesia/analgesia. Atipamezole is a potent alpha 2 antagonist that reverses the effects of alpha 2 agonists. Other alpha 2 antagonists include yohimidine and tolazoline

Answer 24

d. Thoracocentesis ## Footnote This patient has a left sided pneumothorax. Pneumothorax can be secondary to trauma, ruptured bullae, infection, or neoplasia. The radiograph shows an elevated heart off the sternum as well as collapse of the lung lobes. Notice there are no bronchi or vessels extending caudally toward the diaphrgm due to collapse of the lung Pericardiocentesis would be indicated if you had a very large globoid heartm suggestive of pericardial effusion. The heart does not appear enlarged and there is no pulmonary edema making intravenous furosemide a poor choice. Do not confuse a collapsed lung lobe for a lung mass

Answer 25

e. Dolichocephalic ## Footnote Aspergillus is typically a disease of healthy, apparently immunocompetent dogs that are young to middle-aged. Dolichocephalic breeds are overpresented. Immunocompromise does predispose to development of disseminated aspergillosis. Being in a large group of dogs does not increase risk, as it is not a contagious disease. Aspergillus is fairly ubiquitous in the environment, and hunting dogs are probably not exposed significantly more than any other dogs

Answer 26

e. Amputation and treatment with an antifungal ## Footnote Pythium is an aquatic organism that inhabits ponds of the Southeast United States. These organisms have different cell walls than regular fungi, which makes them difficult to treat since most antifungal treatments target fungal cell wall synthesis. Prognosis is extremely poor with this disease and amputation (if the lesions are localized to an affected limb) is currently the best option. Amputation should always be followed with multiple long-term antifungal therapies. Owners should be warned that local postoperative recurrence is common. Dogs are most commonly affected, but this disease can also occur in cats. It has also been reported in humans and horses. Doxycycline is an antibiotic and would not be effective for this disease. Prednisone would be contraindicated for pythium. Lufenuron is a chitin synthesis inhibitor used for flea control and would not be effective. Ivermectin is an anti-parasite drug and would not be effective

Answer 27

e. Breed related ## Footnote Canine pinnal alopecia is a form of pattern alopecia. Pinnal alopecia is most commonly diagnosed in Dachshunds, but can be seen in Chihuahuas, Boston Terries, Bull Terries, Yorkshire Terriers, and Italian Greyhounds. The condition usually occurs in dogs older than 1 year of age and results in slowly, progressive, bilateral pinnal alopecia. The ear margins may become chronically hyperpigmented and thickened. The condition is benign and requires no specific treatment. Distribution of the alopecia is an important key to determining the underlying diagnosis. It may help in distinguishing inflammatory from non-inflammatory causes, thus narrowing down your differential list. Inflammation results in a patchy pattern of alopecia that is not symmetrically distributedl whereas, many of the noninflammatory alopecias have a symmetrical pattern of alopecia. Hypothyroidism often causes alopecia of the tail and may also be associated with alopecia of the nose bridge. Hair loss begins with the pinna at 6 to 9 months of age and may progress to complete pinnal alopecia. Total body alopecia with pigmentation may occur with age. Treatment with oral melatonin may cause hair regrowth with this and other pattern baldness syndromes. Other medications that can be used with variable success are pentoxifylline and Omega 3 oils topically.

Answer 28

c. Blood glucose = 45mg/dL, Serum insulin-high ## Footnote An insulinoma can result in an animal having normal to high insulin levels in the face of low blood glucose levels because the normal controls of insulin secretion are lost

Answer 29

b. Actinomyces ## Footnote This is a filamentous, branching, gram positive bacteria that is a normal inhabitant of the mouth and oropharynx. It is commonly associated with grass awn migration. These are usually contaminated in the oropharynx and the migrate through the body from the respiratory of GI tracts. Many times it takes months to oyears to make a diagnosis. Nocardia is a ubiquitous soil saprophyte found everywhere and is usually introduced via the respiratory tract.

Answer 30

b. Emergency ovariohysterectomy ## Footnote The history and radiograph are consistent with a diagnosis of puometra due to the presence of fluid-filled uterine loops in the caudal abdomen. Pyometra can be managed medically in some cases with hormonal and antibiotic therapy but in most cases, the treatment of choice is ovariohysterectomy to remove the infected tissue and prevent future pyometra at subsequent heats.

Answer 31

a. Polycythemia ## Footnote Renal carcinomas have been associated with erythropoietin secretion, causing elevations in hematocrit as a paraneoplastic syndrome. Hypercalcemia is associated with anal sac adenocarcinomas, lymphomas and other tumors Thrombocytopathy can be seen with hemangiosarcoma and multiplelyeloma Hyperestrogenism can be seen with Sertoli cell tumors

Answer 32

a. Treatment of localized Demodex in young dogs is usually unnecessary. It usually clears up on its own ## Footnote It usually clears up on its own. Ivermectin is usually used to treat generalized Demodex and should not be used in heartworm positive animals and herding dogs like collies and Shepherds (remember that Ivermectin also kills turtles!). Benzoyl peroxide shampoos should be used with demodicosis patients. Although, benzoyl peroxide can not directly kill the mite it aids in follicular flushing. Demodex is a species-specific mite and is not considered zoonotic. Goodwinol is a topical agent sometimes used for localized demodicosis.

Answer 33

b. Sporotrichosis ## Footnote All of these fungal diseases can infect both animals and people. However, they are not considered contagious (not to be confused with infectious) with the exception of Sporothrix. This is because they are mainly acquired from the environment, and transmission from animal to animal is rare. Sporothrix, especially in cats, is a high risk to veterinarians and care should be taken to limit contact with exudates and lesions in cats. Aspergillus is generally considered a ubiquitous fungus that causes infection due to host factors such as immunosucceptibility or certain breed predilections. Cryptococcus is also not a contagious disease (do NOT conduse this with cryptosporidium, which is very contagious and zoonotic). Cryptococcus infection occurs from inhalation of the yeast from the environment, frequently avian habitats, as it survives ideally in pigeon droppings. Essentially, histoplasma, blastobyces, and Coccidioidesare also all environmental diseases as well and not considered contagious.

Answer 34

c. Chloramphenicol ## Footnote Even though this is a human questions, this is something you do need to know for board exams. This potential side effect of chloramphenicol is why it is not allowed for use in food animals and that it is used with caution in companion animals. THe person administering this drug shold take precautions to avoid coming into contact with it.

Answer 35

d. Direct fluorescent antibody test ## Footnote There are no gross pathologic lesions associated with rabies. A diagnostic microscopic lesion is the visualization of Negri bodies. Most commonly they occur in the hippocampus in carnivores and Purkinje cells in herbivores. However, these are only seen 50% of the time. Immunohistochemistry allows strain differentiation and the ability to differentiate vaccine vs. wild-type. RT-PCR has been used on autolyzed brain tissue that is difficult to evaluate with fluorescent antibodies, but this is not the test of choice at this time. Direct FA is the current preferred method of diagnosis; it is both rapid and sensitive. Usuallyimpression of the medulla, cerebellum, and hippocampus are performed.

Answer 36

a. The maximum amount of protein they will tolerate without causing signs of encephalopathy ## Footnote Dogs with hepatic insufficiency or hepatic encephalopathy need to have their protein levels restricted to reduce clinical signs associated with liver dysfunction; however, restricting protein intake to the point where hypoproteinemia develop is excessive. If too little protein is fed to these patients, muscle catabolism may occur. PRoteins derived from meat sources are more prone to causing encephalopathy than proteins from dairy sources due to the high levels of nucleic acids and other nitrogenous compounds found in meat that are converted to ammonia

Answer 37

e. Leptospira ## Footnote The causative agent of leptospirosis is a gram negative organism that stains poorly, if at all. Dark field microscopy is the best way to identify this organism. Leptospira also grows very slowly. There are 7 serovars out of over 220 that tend to cause disease in animals

Answer 38

d. Blood urea nitrogen (BUN) ## Footnote ALT and ALP are liver enzymes and can indicate ongoing damage to the liver or cholestasis but do not tell you anyting about liver function. Creatinine is produced by muscle and cleared by the kidney so it tells you nothing about liver function. Urea is produced by liver and is one measure of liver function; it will be low in cases of liver failure. Other tests of liver function on a routine chemistry panel are cholesterol, glucose, bilirubin, and albumin. Bile acids also test liver function, but are not on a routine chemistry panel. It is important to realize that in cases of end-stage liver failure, the liver function parameters will be affected, while frequently, liver enzymes will be normal.

Answer 39

d. Pre- and post-prandial bile acids test ## Footnote Urate stones in a small breed dog are usually secondary to a portosystemic shunt until proven otherwise. A portsystemic shunt results in blood from the abdomen being shunted away from the liver and into the main circulation. If shunted, the liver does not have an opportunity to detoxify the blood, which among other toxins, is very high in ammonia. The excess ammonia is excreted bia the kidneys. High levels of ammonia can result in formation of ammonium biurate crystals and ultimately stones. An ACTH stimulation test is used to help diagnose hypoadrenocorticism and hyperadrenocorticism. A low dose dexamethasone test is used to help diagnose hyperadrenocorticism. Creatine kinase levels are evaluated when there is a suspected myopathy

Answer 40

d. Ca-EDTA ## Footnote This dog is showing signs of lead poisoning. Clinical signs are primarily gastrointestinal and neurologic. Animals are usually exposed in old buildings or areas of renovation where they have access to lead paint, old batteries, lead fishing weights, etc. Old food and water dishes can also be a source if lead paint was used. Lead blood levels can be measured; however, they do not necessarily correlate with severity of clinical signs. Toxic blood levles are greater than 0.4 ppm. Bloodwork can show an elevated number of nucleated RBCs without anemia. Basophilic stippling is a classic finding with lead toxicity but not specific. Ca-EDTA is the chelator used to treat lead poisoning. Succimer can also be given orally. D-penacillamine has been used to chelate lead, copper, iron and mercury. It is used more commonly for copper toxicity. N-acetylcysteine is used for acetaminophen toxicity and hepatotoxicity. Basophilic stippling can sometimes confused with erythrocytic parasite for which doxycycline may be the treatment of choice.

Answer 41

d. 5-9 hours ## Footnote Platelets have a circulating half life of 5-7 days and red blood cells have an approximate life span of 110 days in dogs NOTE: The approximate life span of RBCs in other species ( in days) is as follows: cats-to, cow-160, horse-145, pig-86, sheep-150

Answer 42

d. Desmopressin acetate (DDAVP) ## Footnote Administration of desmopression results in release of von Willebrand factor, which will help this patient with clotting. Given this dog's breed and elevated BMBT there is a very strong likelihood she is afflicted with von Willebrand's disease. In Dobermans this results in an inability to form a clot. This can be life threatening if the dog is taken to surgery. A whole blood transfusion does not provide an adequate source of von Willebrand factor but may be necessary if the patient's bleeding cannot be controlled despite appropriate pre-operative measures. 1,25 dihydrocholecalciferol is the active form of vitamin D which aids intestinal resorption of calcium. The BMBT does not assess factors 2, 7, 9, 10 and therefore vitamin K is not indicated.

Answer 43

d. Immune mediated hemolytic anemia ## Footnote In immune mediated hemolytic anemia RBCs are coated with immunoglobulins and are then engulfed by macrophages. As a result, the RBC will lose a portion of its cell membrane but not hemoglobin. With the loss of part of the cell membrane, spherocytes appear smaller (without volume loss), no central pallow, and stain deeply red. In iron deficiency, RBC will be hypochromic (less red) and smaller (microcytic) due to less volume. Cobalamin and folate are necessary for DNA synthesis. Giant schnauzers have an inherited cobalamin malabsorption which results in macrocytes and ovalocytes in circulation. Grape and raisin toxicity result in acute renal failure

Answer 44

a. Coccidioidomycosis ## Footnote The travel history and clinical signs are consistent with this answer. Additionally, finding spherules on cytology is pathognomonic for Coccidioidomycosis. Prolonged antifungal treatment will be necessary. Fluconazole is the treatment of choice. Ketoconazole and itraconazole are good choices. With blastomycosis you see broad based budding of the yeast. With Cryptococcus neoforms you will see narrow-based budding.

Answer 45

a. Epithelial origin; carcinoma ## Footnote This is a nasal adenocarcinoma. The classification scheme for tumors by cell of origin and cytologic description is: Carcinoma - These tumors come from epithelial cells including cells of glandular tissues, such as salivary glands, mammary glands, and cells lining most tissues including squamous cells and transitional cells. The cytologic appearance is that of COHESIVE CLUSTERS of cells. Here, you can see some of the tight cellular junctions in the cluster which is typical. Cells are often polygonal in shape. Sarcoma - These tumors come from mesenchymal cells and are named by the specific cell type such as fibroblasts (fibrosarcoma) and osteoblasts (osteosarcoma). Cytologically, they tend to appear as isolated spindle-shaped cell with elongated cytoplasm and often oval nuclei. Round cell tumors - These are 5 round cell tumors and most but not all come from blood cells. They are lymphoma, mast cell tumors, plasma cell tumors, histiocytic tumors, and transmissible venereal tumors. Remember, these are also sometimes also referred to as sarcomas (i.e. lymphosarcoma or histiocytic sarcoma). Cytologically, they appear usually as large populations of cells that are not in defined clusters. The cells have a round shape, often with unique identifiable features such as the purple granules in mast cell tumors

Answer 46

a. Your dog is affected with panosteitis and we need to continue to treat medically. His prognosis is ultimately excellent ## Footnote The radiographs show a patchy opaque region within the medullary canal that might be described as slightly mottled when compared to the left side. One can appreciate this from the lesser trochanter and distal half-way down the femur. There is no evidence of cortical thinning or overt lysis suggestive of a neoplasitc process. If the veterinarian were to palpate this region, it would be very painful to the patient. The cause of panosteitis is currently unknown, but it is thankfully self-limiting and generally only affects dogs less than 2 years of age. German shepherds tend to be predisposed. Treatment is supportive with NSAIDs. Owners are warned that their dog could develop panosteitis in other limbs as well. The hips do not have any overt signs of degenerative changes suggesting hip dysplasia. If the veterinarian were to sedate the patient, it would be prident to check for Ortolani to be on the safe side.

Answer 47

b. Dorsal laminectomy ## Footnote This patient's clinical signs are consistent with neurological deficits. Although you do not have all of the information necessary to reach a definitive diagnosis, you should have been able to deduce that this patient probably needs a dorsal laminectomy to relieve disc compression. In order to definitively diagnose the condition, you would want to proceed with a complete exam, basic bloodwork, and a CT or MRI of the lumbosacral region. Although this patient does exhibit evidence of hip dysplasia radiographically, the clinical signs are not characteristic of a dog with pain secondary to hip dysplasia. There is no indication of osteomyelitis on these radiographs and the clinical signs are not necessarily suggestive of osteomyelitis. Removing the TPLO plate might be tempting if you identified a broken screw (proximal screw of the right tibia). However, this broken screw is likely an incidental finding and does not cause the patient any discomfort since the TPLO site appears to be healed. It is important not to skip ahead to image interpretation without carefully reading the question. Doing so in this case would likely lead you to select the incorrect answer.

Answer 48

c. Avascular necrosis of the femoral head. Perform femoral head and neck ostectomy or total hip replacement ## Footnote Based on the breed and age of the patient, avascular necrosis of the femoral head should immediately be the top differential. This condition is also known as Legg-Calves-Perthes disease and results in a collapse or fragmentation of the femoral epiphysis (as seen on the radiographs) because of a disruption in blood flow. The cause of blood flow interruption is unknown. The condition occurs in young small-breed dogs prior to closure of the capital femoral physis. The condition can be seen bilaterally in 10-17% of patients. Dogs are usually 6-7months of age when they first start showing clinical signs, but the age may range from 3-13 months. Treatment with a femoral head and neck ostectomy (FHO) generally yields excellent results. Alternatively, if owners demand perfect biomechanics, a total hip replacement may be considered, but most veterinarians tend to recommend an FHO. Radiographs will typically show a shortening of the femoral neck as well as osteochondrosis with chronicity, as appreciated in this patient. Note the significant muscle atrophy of the patient's left limb as compared to the right. Patellar luxation should always be a differential in any small breed dog and this should be ruled out via palpation since the patient may not necessarily be luxated at the time the radiograph was taken. The patient's patellas are in a normal position in this radiograph. Septic arthritis of the femoral head is an uncommon condition which is more often seen in large-breed dogs with a history of degenerative joint disease of the hips. They present with acute lameness, severe hip pain, and are usually febrile. Radiographs usually show degenerative joint disease along with potentially lytic areas associated with the femoral head. Neoplasia should also be considered in these cases. Small-breed dogs are less likely to have hip dysplasia as compared to large-breed dogs and should be kept as a lower differential

Answer 49

b. Unilateral artenoid lateralization ## Footnote Resection of the soft palate is performed when dogs have respiratory problems as a result of having elongated soft palate. Resection of the laryngeal saccules is performed when they are everted and causing resrpiatory distress. A partial laryngectomy is performed in cases where there may be a mass or tumor to be removed.

Answer 50

d. Polydioxanone ## Footnote This suture material is absorbable and monofilament. Polydioxanone (PDS) is broken down by hydrolysis and will last longer than catgut, which is better when working with the bladder. On the other hand, you do not want a non-absorbable material as this predisposes the patient to urinary tract infections as a result of the permanent presence of foreign material. Vicryl is a multifilament suture which also has a higher likelihood of failing due to the ability of bacteria to lodge in between the filaments.

Answer 51

c. Simple continuous pattern of an absorbable suture, such as polydioxanone ## Footnote Acute, traumatic, diaphragmatic hernias should be repaired primarily without the use of any "substitute" material for the diaphragm to reduce the risk of complications. It is very rare to have insufficient tissue/muscle to close an acute defect to the diaphragm. Using the native diaphragmatic wall decreases the risk of failure because this technique involves tissue with a direct blood supply as opposed to a mesh type material that is foreign to the body.

Answer 52

b. Temporalis ## Footnote The mass depicted in this three dimensional CT reconstruction involves the coronoid process. The ramus of the mandible consists of three distinct processes, the most dorsal being the coronoid process. It projects into the temporal fossa and provides an area for attachment of the temporalis muscle. The condylar (or condyloid) process is just ventral and slightly caudal to the coronoid process. This process is a point of articulation between the maxilla (retroarticular process) and mandible. Disruption of this region will result in temporomandibular joint luxation. The most ventral process is the angular process. This structure provides an area for attachment of the digastricus muscle. The masseter muscle inserts laterally on the mandible, while the pterygoid muscle inserts medially. The masseter, pterygoid, and temporalis muscles function to close the mouth while the digastricus opens the mouth.

Answer 53

c. At least 20 mg/dL less than the blood glucose ## Footnote The correct answer is at least 20 mg/dL less than the blood glucose. The image depicts a perforated colon, which will result in a septic abdomen due to the normal colonic flora emptying into the abdomen. A concentration difference \> 20 mg/dL between blood and peritoneal fluid glucose concentration provides a rapid and reliable means to differentiate a septic peritoneal effusion from a nonseptic peritoneal effusion in dogs and cats.

Answer 54

d. This patient is expected to have cranial drawer on the left hind limb ## Footnote Based on the radiographic finding of marked stifle effusion of the left stifle noted by the displacement of the infrapatellar fat pad (cloudy area as compared to right stifle) this patient likely has a cranial cruciate ligament rupture. The history and signalment help you to arrive at this top differential. Other differentials such as immune mediated polyarthritis or joint infection would be ruled out after a thorough orthopedic exam. During this exam one can expect to find tibial thrust, cranial drawer, and pain on extension of the stifle. Cranial cruciate ligament injuries are the most common orthopedic problem seen in dogs and should be a high differential for any large breed, active dog, with an acute history of lameness. Patellar luxation is relatively uncommon in large breed dogs and would be a very low differential. The right stifle radiograph has no effusion associated with the joint but does show some boney changes that are likely incidental, perhaps from prior trauma, at the distal aspect of the patella.

Answer 55

b. Your dog likely has osteochondrosis dissecans of the medial trochlear ridge and removal of the flap and curretage is recommended ## Footnote The radiographs show evidence of effusion when compared to the contralateral limb. There is also a widened joint space of on the medial aspect at the level of the tibio-tarsal joint with flattening of the medial trochlear ridge. Those specific findings are highly suggestive of osteochondrosis dissecans (OCD). The signalment of the patient also fits with this diagnosis. Young dogs are not typically affected by fragmentation of the medial trochlear ridge. If you selected this answer you are probably confusing yourself with a fragmented medial coronoid process which is a component of elbow dysplasia. A joint infection of six weeks duration is highly unlikely and we would expect the dog to be more clinical if it was present for that length of time. Lethargy, inappetance, and pyrexia would be expected. The radiographic findings would probably show severe degenerative changes if it were ongoing for six weeks. A ligamentous injury cannot be ruled out on this radiograph alone. Stress radiographs would be necessary to see if there is excessive laxity of the joint. If the findings consistent with OCD were not present, offering the owners stress radiographs as the next step would be reasonable.

Answer 56

d. They are older intact males ## Footnote This is a case of a perineal hernia. Older intact male dogs are most commonly affected. Overrepresented breeds include Boxers, Collies, Kelpies, Pekingese, and Boston terriers. The hernia results from a weakened pelvic diaphragm. It is thought that there may be a hormonal component which results in weakening with time.

Answer 57

c. Esophagopexy in conjunction with a left-sided gastropexy ## Footnote Performing these will help prevent the esophagus from herniating back into the thoracic cavity. The left-sided gastropexy increases the barrier pressure at the gastroesophageal junction. Resection and anastomosis of any region of the esophagus is associated with significant morbidity and mortality and should be avoided if possible. Additionally this does not necessarily address the problem. Placement of an esophagostomy tube does not fix any problems. Perhaps if medical management is pursued, a gastrostomy tube or jejunostomy tube is more appropriate. Plication of the small intestines was previously performed in animals that had intestinal intussusceptions and later found to not be substantially beneficial.

Answer 58

a. Recession trochleoplasty ## Footnote This technique is part of a surgical repair method for luxating patellas. Weight reduction is nearly always a therapeutic component to managing orthopedic disease. Leveling of the tibial plateau and cranial transposition of the fibular head are two surgical options for correcting a torn cranial cruciate ligament.

Answer 59

d. Carpal ardesis ## Footnote Arthrodesis is the treatment of choice for severe hyperextension injuries to the carpus. This procedure is accomplished by debridement of the articular cartilage of the joints, implantation of a cancellous autograft into the debrided joint spaces, and fixing a bone plate across the injured joints.

Answer 60

a. Excellent, \>95% of dogs recover ## Footnote This is a case of panosteitis based on the young age of the patient and radiographic presence of focal intramedullary densities within the humeral diaphysis. Minor differentials could include osteomyelitis. Panosteitis is a self-limiting, painful condition characterized by limping and lameness. It typically affects the long bones of young dogs, usually between the ages of 5 to 18 months. It can occur with any breed, but it is more common in medium- to large-sized dog breeds. Treatment is primarily supportive consisting of limiting activity and anti-inflammatory drugs. Pain lasts from weeks to months and resolves in nearly all cases. While these treatments reduce the pain associated with the condition, they may not alter the duration or course of the disease.

Answer 61

d. Pelviv radiographs to evaluate for evidence of dysplasia ## Footnote A bunny-hopping gait is most often seen in cases of hip dysplasia. Radiographs of the hips would be the next best step. Since there is no cranial drawer movement, there is not likely a CCL rupture. Panosteitis can be seen in younger dogs which are growing and would cause pain in the long bones. Typically lameness from rickettsial disease is painful and may affect multiple joints or limbs.

Answer 62

b. Hypertrophic osteodystrophy ## Footnote The radiograph shows the classic signs of hypertrophic osteodystrophy. There is a double physeal line in the metaphysis and areas of bony proliferation. The metaphyses are flared as well. Panosteitis has a patchy trabecular pattern. Hypertrophic osteopathy is a disease of older animals generally associated with metastatic disease. The main radiographic finding is periosteal reaction around the metacarpals, tarsals and digits. More than one limb is usually affected and if seen, further diagnostics to look for a primary site of neoplasia is warranted. Soft tissue swelling and joint effusion are seen with septic arthritis and bony changes can be seen with chronic disease.

Answer 63

b. Partial meniscectomy ## Footnote There is no reason to remove the menisci, as these are not involved with patellar luxation. A wedge resection involves making a deeper trochlear groove for the patella to slide in. Lateral imbrication and transposition of the tibial tuberosity will help pull the patella a little more laterally, as they are usually predisposed to luxating medially.

Answer 64

c. Early return to function ## Footnote With articular fractures, the 3 major goals of the clinician are: 1) Rigid fixation of the fracture fragments; neglecting to do this will result in loose fracture fragments within the joints that will promote osteoarthritis. 2) Anatomic realignment (50% or even 75% is not adequate with articular fractures, in contrast to long bone fractures) 3) Early return to function. With long bone fractures, extended rest is recommended to promote stability and healing of the bone. The opposite is true in articular fractures where prolonged rest after repair will promote fibrosis, causing decreased range of motion in the joint.

Answer 65

c. Prednisone and azathioprine ## Footnote This case is most consistent with immune-mediated polyarthritis (IMPA). IMPA is often classified as being erosive or nonerosive. This case is an example of the nonerosive form based on the lack of radiographic evidence of cartilage or subchondral bone destruction. The erosive form is rare and is thought to account for \<1% of the cases of IMPA. Nonerosive IMPA can be associated with a variety of systemic diseases or precipitating factors including systemic infectious, inflammatory or neoplastic disease or reactions to drugs or vaccines but it is most commonly idiopathic with no association to another disease process. In the described case, no risk factors or signs of concurrent disease were mentioned. Tick-borne arthropathy is less likely with the negative tick titers obtained, but since not every type of tick can be tested for, some clinicians may opt to treat with an antibiotic like doxycycline concurrently with the immunosuppressive drugs. The clinical signs associated with IMPA are anorexia, weight loss, fever, lethargy, and lymphadenopathy. Up to 25% of dogs present with only nonspecific signs of systemic illness and without apparent gait abnormality or joint effusion. It is an important consideration for dogs with fever of unknown origin and may be the cause up to 20% of the time. IMPA is diagnosed by synovial fluid analysis although additional baseline diagnostics are indicated to screen for potential systemic or infectious causes. Normal synovial fluid is clear and viscous with \<2.5 g/dl protein and \<3,000 cells/ul with predominantly mononuclear cells. Joint fluid in IMPA may be thin, turbid, and increased in volume with higher amounts of protein and cells, often primarily nondegenerate neutrophils. Treatment of idiopathic IMPA centers on immunosuppressive therapy, often starting with prednisone and sometimes including an additional immunosuppressive drug such as azathioprine or cyclophosphamide. About 80% of dogs will respond to immunosuppressive doses of prednisone; however, about one half of dogs require long-term or additional drug therapy to maintain remissio

Answer 66

b. Dlmatians have a genetic defect in making allantoin from urates in their liver. The low solubility of urates predisposes the dogs to forming urate stones, which can cause urinary tract obstructions. ## Footnote The low solubility of urates predisposes the dogs to forming urate stones which can cause urinary tract obstructions. Medical management involves feeding a low purine diet to neutralize or alkalinize the urine pH and administration of allopurinol, a xanthine oxidase inhibitor.

Answer 67

e. Xanthine ## Footnote Allopurinol is used in the treatment of urate stone forming Dalmatians. It acts by inhibiting the enzyme, xanthine oxidase, which metabolizes xanthine. The idea is that by stopping the purine metabolism pathway at this point, uric acid will not be formed in high quantities. However, if given at too high of a dose, xanthine will accumulate to levels where xanthine stones will form.

Answer 68

d. Bacterial or white blood cell casts in urine ## Footnote Bacterial or white blood cell casts are highly suggestive of a past or present bacterial infection in the kidneys. Bacteria or white blood cells in the urine may be due to cystitis. Small, irregular kidneys may be due to any chronic pathology in the kidneys. Pain on abdominal palpation can be caused by pain from any abdominal organ or structures adjacent to the abdomen. Other signs associated with pyelonephritis include fever, anorexia, depression, and vomiting. A nephropyelogram may show blunted, dilated calices and dilated, tortuous ureters. Renal biopsy and culture would give the definitive diagnosis of pyelonephritis.

Answer 69

d. Struvite urolithiasis. Treat with culture-based antibiotics, and either dietary dissolution or surgical removal of stones ## Footnote Large bladder stones in the presence of UTI and alkaline urine are usually struvite, particularly when accompanied by struvite (magnesium ammonium phosphate) crystalluria. In dogs, struvite stones are almost invariably infection-associated. The infecting organisms are usually urease-producers (Staphylococus, Proteus, Klebsiella, some E. coli) which alkalinize the urine and favor struvite formation. The single most important long-term management is prevention of infection. Calcium oxalate stones are usually small (1 cm or less), are often present in the absence of UTI, and cannot be dissolved. Cystine stones occur most often in Newfoundland dogs, dachshunds, and bulldogs. They are radiolucent and occur due to metabolic defects. Urate stones are usually small and many. They are frequently radiolucent and can be related to underlying liver disease.

Answer 70

b. The dog has urate stones in its bladder ## Footnote The dog is described as having a portosystemic shunt which is often accompanied by urate stones in the bladder. Urate stones (and cysteine stones) are radiolucent, so they can't be detected by radiography. Remember "I can't C U": ("C" is for cysteine, and "U" is for urate).

Answer 71

b. Tell the owner the dog has a guarded to poor prognosis and may need hemodialysis ## Footnote 4-MP and ethanol act by preventing alcohol dehydrogenase from converting ethylene glycol to its toxic metabolites. In animals where oliguric renal failure has already begun, most of the ethylene glycol will already have been metabolized, so there is no benefit to giving ethanol or 4-MP. Activated charcoal should only be given if the ethylene glycol was ingested within 2 hours.

Answer 72

b. Fanconi syndrome ## Footnote Fanconi syndrome is an inherited disease in Basenjis. The disease involves renal tubular defects causing an abnormal loss of electrolytes and solutes leading to hypophosphatemia, hypokalemia, and metabolic acidosis. DM is less likely because serum glucose is normal. The lab abnormalities present in this dog are not consistent with pyelonephritis. Pyometra is not a viable choice as the signalment describes a male.

Answer 73

d. Metaphysis ## Footnote Hypertrophic osteodystrophy (HOD) is a condition seen in young, growing large breed dogs. It affects the metaphyses of all long bones and appears as an abnormal radiolucent line within the metaphysis. The disease is usually self-limiting but can cause limb deformities or systemic illness. The etiology is unknown but may be correlated with Ca/P levels and balance, vitamin C deficiency, and certain diseases including distemper.

Answer 74

b. Ventrodorsal ## Footnote Pleural effusion obscures the heart completely on a dorsoventral radiograph and at least partially on lateral radiographs. Ventrodorsal positioning usually moves the pleural fluid away from the heart and allows for a radiographic view of the heart to be obtained. Of course, in dyspneic animals, it may not be wise to position them ventrodorsally.

Answer 75

c. Epiphysis and physis ## Footnote A type I Salter-Harris fracture is physeal only. Type II involves the physis and metaphysis, type III involves the physis and epiphysis, type IV involves physis, metaphysis, and epiphysis, and type V is a compression injury to the physis.

Answer 76

b. Polyostotic, aggressive ## Footnote There are multiple lytic lesions in the cervical and thoracic vertebrae, especially visible in C2 and in the spinous processes of the T1-T8. There are also lytic lesions in the proximal humerus of one leg and in the bones of the skull.

Answer 77

a. Pulmonary neoplasia ## Footnote Hypertrophic osteopathy is visible as periosteal proliferation in the diaphyses of affected bones. Usually the metacarpal and metatarsal bones are affected first, and it may progress to the long bones. Lameness, pain, and swelling are usually evident. Joints are unaffected. The cause is usually primary or metastatic pulmonary neoplasia, although other diseases in the thorax including bronchopneumonia, Spirocerca infection, or congestive heart failure, may also be associated. Less commonly, abdominal neoplasia may be seen with this condition.

Answer 78

b. Osteosarcoma ## Footnote The abnormality in the radiograph is multiple pulmonary nodules consistent with metastatic neoplasia. Systemic fungal disease would be a reasonable differential for this radiographic pattern but is not as good of a choice, especially with no evidence of hilar lymphadenopathy. Aspiration pneumonia would cause an alveolar infiltrate centered in the cranioventral lung region, and penetrating trauma would likely cause pneumothorax. There is no evidence of pneumothorax in this study.

Answer 79

d. Fecal float ## Footnote Hookworms (Ancylostoma and Uncinaria) are intestinal parasites that suck blood and can cause anemia, enteritis, coughing during larval migration, and dermatitis. Any young dog that is failing to thrive and/or has pale mucous membranes should be tested for intestinal parasites. Hookworm dermatitis, also called Ancylostomiasis is typically seen in conditions with poor sanitation and/or in kennels. Hookworms can be transmitted in utero, during nursing, or via 3rd stage larva penetrating the skin. The most commonly affected skin areas are the pads and interdigital spaces of the feet, but can include any surface that contacts the ground. The larva migrate through the dog's tissues before arriving in the intestines. They cause significant anemia, failure to thrive, or sudden death in young dogs. In mild cases, deworming protocols are often enough; with severe cases blood transfusions and parenteral treatments are often necessary. Skin scraping and impression smears of the affected skin areas are typically unrewarding for isolating parasites. A PCV/TP would show signs of anemia, but not the underlying etiology. Complete blood cell count and chemistry will often show anemia that is regenerative and an eosinophilia. Radiographs would be unrewarding in this case. A biopsy may show migrating larva if biopsied soon after trauma, however this is not a diagnostic test routinely used.

Answer 80

c. Praziquntel ## Footnote Pyrantel and ivermectin are not known to be effective against Taenia infections. Fenbendazole is effective against Taenia pisiformis, but not other subspecies of Taenia, making it a less desirable answer choice.

Answer 81

c. Tetracycline antibiotics ## Footnote The causative agent for the dog's clinical signs is Neorickettsia helminthoeca. Treatment of choice for this rickettsial agent is tetracycline antibiotics. The fluke itself is not responsible for the clinical signs, but may be treated effectively with Praziquantel.

Answer 82

c. Ixodes pacificus ## Footnote Ticks acquire the infection at any stage and are most likely to get it from the white-footed mouse, Peromyscus leucopus. Dermacentor variabilis and Dermacentor andersoni are known to transmit Rocky Mountain Spotted Fever. Amblyomma americanum may transmit canine granulocytic ehrlichiosis which is caused by E. ewingii and Anaplasma phagocytophila. Rhipicephalus sanguineus is known to transmit Ehrlichia canis.

Answer 83

c. Approximately 1400 days Single solitary liver masses are generally considered a surgical disease as long there is no overt evidence of metastasis or concern that the mass is a metastatic lesion as opposed to a primary tumor arising from the liver. Primary liver masses include hepatomas, hepatocellular carcinomas, bile duct adeonomas, bile duct carcinomas, and rarely, neuroendocrine tumors. Hepatocellular carcinomas are the most common liver tumor of dogs and second most common in cats. Adenomas will have a better prognosis, however hepatocellular carcinomas generally carry a good prognosis after surgical excision as well. Bile duct carcinomas have a much more guarded prognosis with an average survival time of approximately 6 months. The prognosis for neuroendocrine tumors of the liver is poor.

Answer 84

a. Sertoli cell tumor ## Footnote The tumor sometimes secretes estrogen and other hormones, which can lead to this syndrome.

Answer 85

d. Strongly recommend chest radiographs and biopsy prior to initiating treatment ## Footnote This radiograph has a component of lytic and proliferative lesions that cross the joint. The differentials include neoplasia, fungal osteomyelitis, or bacterial osteomyelitis. Since the bony involvement is crossing the joint, it is most likely a synovial cell sarcoma. Osteosarcoma, fibrosarcoma, and chondrosarcomas are less likely to cross a joint as seen in this image. The marked lytic component seen should eliminate severe osteoarthritis as a differential. Anti-fungal therapy or any definitive treatment should ideally not be initiated until a diagnosis is obtained. The radiograph shown here was actually taken after obtaining a core biopsy of the bone for histopathology.

Answer 86

a. Polycythemia ## Footnote Renal carcinomas have been associated with erythropoietin secretion, causing elevations in hematocrit as a paraneoplastic syndrome. Hypercalcemia is associated with anal sac adenocarcinomas, lymphomas and other tumors. Thrombocytopathy can be seen with hemangiosarcoma and multiple myeloma. Hyperestrogenism can be seen with Sertoli cell tumors. Hyperadrenocorticism is caused by functional adrenal or pituitary tumors.

Answer 87

b. This patient has metastatic lesions throughout the lungs and only palliative treatment can be recommended ## Footnote This dog was not staged prior to surgical removal of the mass and likely had visible metastatic nodules at the time of surgery. The only other potential differential with this radiographic finding would be granulomatous disease which is unlikely given the history.

Answer 88

d. Prednisone ## Footnote This is a case of lymphoma. The cytology depicts the classic finding of a population of lymphoid cells that are predominantly lymphoblasts based on their size and characteristics. If you were unsure about their size due to magnification, there is a neutrophil in the lower left corner for comparison. The lymphoblasts are considerably larger than the neutrophil. Mature lymphocytes would be smaller than a neutrophil. Note that there is a mitotic figure in the middle of the slide. There are many treatments and protocols for lymphoma and some of the main agents known to have efficacy are prednisone, doxorubicin, cyclophosphamide, vincristine, L-asparaginase, and lomustine. There are many other efficacious chemotherapeutics for lymphoma but carboplatin is not considered a first line treatment for lymphoma in dogs. The other drugs listed are antifungal (itraconazole), antibiotic (doxycycline) and anti-parasitic (milbemycin).

Answer 89

b. Mast cell tumor ## Footnote Mast cells contain granules with inflammatory mediators including heparin and histamine and commonly cause local inflammation. They can also cause paraneoplastic signs associated with hyperhistaminemia and hyperheparinemia. Half of mammary tumors in dogs are benign and half are malignant. Even the malignant ones do not usually have associated inflammation with the noteworthy exception of a relatively rare type of tumor called an inflammatory mammary carcinoma that carries a very poor prognosis. Hemangiosarcoma and lymphoma are both malignant tumors but are not usually associated with extensive inflammation. Cutaneous melanoma in the dog is benign in 80-90% of cases in contrast to humans.

Answer 90

d. Schistocytes ## Footnote Schistocytes are fragmented red blood cells that are mechanically broken up due to the irregular vessels and fibrin strands they pass through in hemangiosarcoma patients. Other typical findings on a CBC in a patient with hemangiosarcoma are thrombocytopenia, anemia (although not with Heinz bodies), and leukocytosis.

Answer 91

a. Start a tyrosine kinase inhibitor chemotherapy drug ## Footnote Under the Patnaik grading system, grade 3 tumors are highly metastatic. Mast cell tumors are highly responsive to radiation therapy, but with clean excision and wide surgical margins, local recurrence is unlikely. Metastasis is the primary concern and a wait and monitor approach is not advised. Even with no evidence of metastasis at the time of surgery, chemotherapy should be initiated as soon as possible. Common protocols include single agent or alternating vinblastine and lomustine. Tyrosine kinase inhibitors, such as toceranib (Palladia) and masitinib (Kinavet, which is no longer available), target c-kit, a stem cell factor receptor involved in mast cell proliferation and differentiation. Palladia and Kinavet are FDA approved for treatment of high-grade canine cutaneous mast cell tumors.

Answer 92

b. Bone marrow biopsy, serum electrophoresis ## Footnote This dog has signs and bloodwork findings that are consistent with but not specific for multiple myeloma. The hypercalcemia and hyperglobulinemia are both mild and are consistent with this diagnosis but would not be sufficient alone to jump to that conclusion. The key finding in these case is the radiographic evidence of multiple punctate lucencies including in the body of C4, several of the thoracic dorsal spinous processes, the left ilium, and the right and left humeral diaphyses. These lesions are strongly suggestive of multiple myeloma; however, definitive diagnosis of multiple myeloma requires satisfying at least two of the following criteria: 1. Monoclonal gammopathy 2. Radiographic evidence of osteolytic bone lesions (satisfied in this case) 3. \>5% neoplastic cells or \>10-20% plasma cells in the bone marrow 4. Immunoglobulin light chain proteinuria (Bence-Jones proteinuria) Therefore, the best answer in this question is to perform serum electrophoresis to assess monoclonal gammopathy and a bone marrow biopsy to look for neoplastic infiltration of plasma cells.

Answer 93

a. Cardiotoxicity ## Footnote In addition to the usual side effects of chemotherapeutic drugs such as myelosuppression and GI side effects, a major concern with adriamycin administration is dose dependent cardiotoxicity. The drug that causes ileus is vincristine. The drug that causes anaphylaxis is L-asparaginase. The drug that causes nephrotoxicity is cisplatin. The drug that causes cystitis is cyclophosphamide.

Answer 94

d. Aggression ## Footnote More males than females present to veterinary behaviorists for aggression. The other diseases listed have been reported or suggested to occur more frequently in females in some reports.

Answer 95

b. The dog likely has an inherited defect in cellular immunity. The dog should no ## Footnote The dog should not be bred. Generalized demodicosis in juveniles and puppies is usually caused by an inherited defect in cell immunity. They should be treated with a mite killing agent like ivermectin, amitraz, or milbemycin, as well as with oral antibiotics for secondary bacterial infections. Spontaneous remission of the infection can occur, but the prognosis is always guarded. Demodex mites are part of the natural flora of a dog's skin, so they are normally present all the time. Adult dogs that develop generalized demodicosis are usually immune-suppressed.

Answer 96

a. German Shepherd Dog ## Footnote EPI is believed to be an autosomal recessive trait in German Shepherd Dogs that results in atrophy of the exocrine pancreas. Dogs lose the ability to digest fat and protein and become emaciated. They have voluminous, soft feces, a voracious appetite, and may develop pica. The trypsin-like immunoreactivity (TLI) is diagnostic for EPI. Treatment entails adding powdered pancreatic enzyme extract, or raw pancreas to meals. These dogs should not be bred.

Answer 97

a. Dachshund ## Footnote The primary inherited form of this condition almost exclusively occurs in Dachshunds. Other dogs may get a form of the condition secondary to other skin diseases. The condition is characterized by hyperpigmentation of the axillary and groin regions and can spread to other parts of the body. Secondary bacterial infections, yeast infections, and seborrhea commonly develop in the affected regions. The mode of inheritance has been proposed to be autosomal recessive or polygenic inheritance.

Answer 98

c. Metabolic acidosis ## Footnote A low bicarbonate and total CO2 level is consistent with a metabolic acidosis. An elevated blood lactate of greater than 2.0 mmol/L implies that there is anaerobic metabolism occurring in this patient as a result of inadequate tissue perfusion, perhaps due to bleeding and trauma. Nothing can be said about respiratory acidosis or alkalosis because no PaCO2 or pH is provided.

Answer 99

e. 6 mEq/hr ## Footnote The maximum safe rate of potassium infusion is 0.5 mEq/kg/hr. As this dog weighs 12 kg, the maximum is 6 mEq/hr. This is one of those rates that you need to know. Administering potassium more rapidly than this can result in fatal arrhythmias.

Answer 100

d. Thoracocentesis ## Footnote This patient has a left sided pneumothorax. Pneumothorax can be secondary to trauma, ruptured bullae, infection, or neoplasia. The radiograph shows an elevated heart off the sternum as well as collapse of the lung lobes. Notice there are no bronchi or vessels extending caudally toward the diaphragm due to collapse of the lung. Pericardiocentesis would be indicated if you had a very large globoid heart, suggestive of pericardial effusion. The heart does not appear enlarged and there is no pulmonary edema making intravenous furosemide a poor choice. Do not confuse a collapsed lung lobe for a lung mass.

Answer 101

c. Compensatory increase in mean arterial pressure to maintain cerebral perfusion pressure ## Footnote Cerebral perfusion pressure= Mean arterial pressure - intracranial pressure or (CPP=MAP-ICP). This response is seen in situations where intracranial pressure increases such as in brain trauma. In this case, you need to think before you intervene to decrease your patient's mean arterial pressure as this might eliminate cerebral blood flow and kill your patient.

Answer 102

e. Morphine and thiopental ## Footnote In this case, thiopental is contraindicated because the patient is a sighthound. Thiopental is an ultra-short acting barbiturate. Recovery depends on redistribution to tissues, including fat. Because sighthounds have very little fat, they have prolonged recoveries and greater complications with these drugs. Morphine is contraindicated in this patient due to the ulcerating mast cell tumor. Morphine can cause histamine release and should be avoided in mast cell tumor patients.

Answer 103

Pinnal-pedal reflex, clinical signs, superficial skin scrape ## Footnote A superficial skin scrape is most useful. A deep skin scrape is used for Demodex mites, which reside in the hair follicles. Superficial skin scraping is indicated for Sarcoptic mange, since this mite lives in the stratum corneum. Pinnal-pedal reflex can be positive in 70% of Sarcoptic mange infestation but can also be positive in any dog with pruritus. Clinical signs are helpful because Sarcoptes typically infects the non-haired portions of the skin such as the ear pinnae, elbows, hocks, and ventral abdomen. If the mite is not found on skin scraping and you have clinical signs indicative of Sarcoptes then a therapeutic trial is warranted. Keep in mind that in most cases you will not be able to find the mite. A trichogram would not be indicated. This method can be used to diagnose dermatophytosis and sometimes Demodex. Histopathology will reveal a perivascular dermatitis that is non-specific. Rarely are the mites found on histopathology.

Answer 104

c. Benign Neglect ## Footnote Histiocytomas are typically benign and will often present as a small, raised mass that may or may not be ulcerated. Fortunately, these masses usually regress on their own, and surgical or medical intervention is typically not necessary.

Answer 105

c. Dermatophytosis ## Footnote Pemphigus and discoid lupus are autoimmune conditions that can result in ulcerative nasal dermatitis with loss of cobblestone appearance. Cutaneous lymphoma, in rare cases, can affect just the nose. Mucocutaneous pyoderma can also result in similar signs, but this condition usually has involvement in other areas such as the mucocutaneous junctions of the mouth, prepuce, and anus. Dermatophytosis (ringworm) often affects the muzzle; however, it rarely affects the nasal planum. This is because dermatophytes live in hair follicles and there are no hair follicles on the nasal planum. Many times you will observe dermatophytosis on the muzzle and the lesions will stop abruptly where the nasal planum starts. The next step for this dog would be to biopsy.

Answer 106

e. Fluconazole, free T4 ## Footnote From the options listed, fluconazole is the best treatment plan for this dog's Malassezia dermatitis. Griseofulvin is an antifungal but is expensive and causes myelosuppression and gastrointestinal upset; it is not the first choice for Malassezia dermatitis. Other azoles like itraconazole and ketoconazole are also good choices. Terbinafine is being used more often for Malassezia dermatitis since it has fewer side effects than azoles. Ketoconazole, itraconazole, and fluconazole can be hepatotoxic. Underlying causes of Malassezia dermatitis include allergies, endocrinopathy, immunodeficiency syndromes, and other systemic illnesses. This dog is presenting with classic signs of an endocrinopathy with initially non-pruritic symmetrical alopecia. The clinical signs of lethargy and weight gain along with the blood work results is indicative of hypothyroidism, and your next diagnostic step would be a free T4. Intradermal testing is not recommended at this time, since the dog was initially not itchy and only became pruritic presumably after infection with Malassezia. Doxycycline would not be indicated since it is an antibiotic.

Answer 107

d. The disease is familial, and is often cyclic and will regress ## Footnote Familial dermatomyositis is a familial disease seen in Collies, Shetland sheepdogs, and other collie breeds. Diagnosis can be made with skin or muscle biopsies, but can be difficult as the clinical and histopathologic signs can wax and wane. Inciting causes can include vaccinations, sunlight, viral infections, or drugs. Some cases; however, will come and go without obvious inciting causes. Some cases can become severe enough to include muscle atrophy; megaesophagus has also been seen with this disease. Treatments are often symptomatic and supportive and include Vitamin E supplements, Omega 3 fish oils, treatments for any secondary bacterial infections, and pentoxifylline. Prednisone can also be used to get more severe cases under control. Avoiding prolonged sun exposure can also help. Educating the owner on the fact that signs will reoccur despite treatment can alleviate some owner frustrations. Often times signs will regress with or without treatments. Educate owners on neutering animals to prevent propagation of diseased animals.

Answer 108

b. Panosteitis ## Footnote Familial Shar Pei Fever (FSF) is characterized by high fever and unilateral or bilateral tarsal swelling as seen in the photo. This swelling affects tissues around the joint, rather than within the tarsus itself. FSF may be a distinct entity from amyoloidosis but animals with FSF are predisposed to amyoloidosis, resulting in proteinuria. Panosteitis is not associated with FSF.

Answer 109

c. Amitraz (Mitaban) ## Footnote This is a case of generalized demodicosis which can occur in older dogs as well as young dogs. It is caused by the commensal mite, Demodex canis, and is often secondary to an underlying disease or immunosuppression. There are several treatment options (and you should probably know them all) but the only FDA-approved treatment is Amitraz (Mitaban). Ivermectin and milbemycin are also used to treat this condition in part because it is difficult to obtain Mitaban. Mitaban is used as dip and should be administered in a hospital, which is time consuming when there are other treatment options that can be similarly effective although used "off-label". Mitaban should be used cautiously in animals with skin lesions since more systemic absorption of Mitaban will occur which increases the likelihood of toxic affects.

Answer 110

b. Color change may occur seasonally ## Footnote This is seasonal nasal hypopigmentation. Season associated lightening of the nasal planum occurs during winter months and can darken in the spring and summer. Complete depigmentation is not noted. Hypopigmentation and discoloration of the nose and mucocutaneous junctions can vary from benign immune-mediated diseases, such as vitiligo that lower the amount of melanocytes in the skin to seasonal variations in coloring, commonly called a "Dudley Nose" or "Snow Nose". Certain breeds are more predisposed than others, such as Siberian Huskies, Golden and Labrador Retrievers, and Bernese Mountain Dogs. This can be seen in any breed. With vitiligo, which is a benign immune related depigmentation, antimelanocyte antibodies can be found in circulation and a biopsy will show decreased melanocytes. Typically multiple areas will be affected, including ear tips, footpads, claws, and hair coat. Breeds predisposed to vitiligo can include German Shepherd Dogs, Collies, Rottweilers, Doberman Pinschers, and Giant Schnauzers There are no treatments to prevent these disorders, and they typically cause no harm to the animals.

Answer 111

d. Firocoxib ## Footnote Pemphigous vulgaris is an auto-immune disease which requires immunosuppressive therapy. This patient is likely on a steroid and possibily other immunosuppressives. Firocoxib (Previcox) is a nonsteroidal anti-inflammatory (NSAID) with specific inhibition at the Cox-2 sites and sparing of Cox-1 receptors. As with any NSAID, it is contraindicated to give this medication in conjuction with a steroid due to the high likelihood of side effects. Combination of an NSAID with a steroid may result in renal compromise and failure, in addition to gastric ulceration and increased risk of gastrointestinal perforation. The other medications listed have no known adverse side effect when given with a steroid. Enrofloxacin has been known to cause blindness in cats at high doses. Maropitant is a popular anti-emetic/anti-nausea medication used in small animals. This medication has the potential of accumulating, therefore a washout period is recommended if used for more than 5 days. Fluconazole is a fungistatic triazode. It has the potential for hepatoxicity and therefore patients on this medication should have their liver parameters periodically evaluated.

Answer 112

e. Glucocorticoids ## Footnote Based on physical exam findings, bloodwork, and history, fungal infection should be the primary differential. This is blastomycosis, a fungus whose spores are found predominantly throughout Ohio, Mississippi, and Tennessee. Spores are typically inhaled causing pulmonary disease before disseminating throughout the body. Commonly affected organs include the skin, bones, eyes, lymphatic system, and lungs. Less commonly affected organs can include the prostate, mammary glands, heart, and CNS. Diagnosis can often be made on cytology of draining wounds. Biopsy of affected areas can also demonstrate organisms. AGID and antigen testing can detect Blastomycosis as well; however, you may have false negative AGIDs with early infection and the urine antigen test can be cross-reactive with Histoplasmosis. Treatment can be difficult and includes antifungals, often long term, and NSAIDs. Glucocorticoids are often contraindicated as they may cause further immunosuppression. Some studies have shown that brief use of intravenous dexamethasone in the face of life threatening dyspnea during treatment with anti-fungals may be beneficial, but this is currently still under scrutiny. Zoonotic transmission is generally low in living animals. Few reports of infection through dog bites have been reported. Necropsies of infected animals have resulted in infections through needle sticks, cuts, or inhalation. Warn owners the disease is an environmental pathogen, and can cause infection in people living in endemic areas. Radiographs may show osteomyelitis of bones and nodular to diffuse interstitial patterns in the lungs. Pulmonary signs can mimic metastatic lesions. Severity can indicate overall prognosis.

Answer 113

a. Central diabetes insipidus ## Footnote Males with Sertoli cell tumors may develop bilateral alopecia with occasional pruritus and papular eruptions. Hypothyroid dogs often develop alopecia, seborrhea, and pyoderma. Hyperadrenocorticism patients commonly develop hyperpigmentation, alopecia, calcinosis cutis, seborrhea, and pyoderma.

Answer 114

c. Ivermectin and prednisone therapy ## Footnote Acral lick dermatitis is considered a chronic and repetitive condition in which a dog continuously traumatizes a region as a result of obsessive licking. The licking is usually secondary to pruritis from allergies and will lead to infection. There could be multiple causes for this such as a neuropathy or underlying orthopedic disease; however, this behavior is considered to be obsessive-compulsive, and the patient may need to be evaluated for other anxiety related behaviors. Since these lesions are not parasitic in origin the answer choice with Ivermectin is considered the poorest treatment option. All other choices may be used alone or in combination to help break the cycle and achieve healing of the lesion. Triamcinalone is a steroid. Clindamycin is an antibiotic. Fluoxetine (aka Prozac) is used to treat depression and obsessive-compulsive disorders. Basket muzzles and e-collars are commonly used as well to help stop the licking.

Answer 115

e. Amputation and treatment with an antifungal ## Footnote Pythium is an aquatic organism that inhabits ponds of the Southeast United States. These organisms have different cell walls than regular fungi, which makes them difficult to treat since most antifungal treatments target fungal cell wall synthesis. Prognosis is extremely poor with this disease and amputation (if the lesions are localized to an affected limb) is currently the best option. Amputation should always be followed with multiple long-term antifungal therapies. Owners should be warned that local postoperative recurrence is common. Dogs are most commonly affected, but this disease can also occur in cats. It has also been reported in humans and horses. Doxycyline is an antibiotic and would not be effective for this disease. Prednisone would be contraindicated for pythium. Lufenuron is a chitin synthesis inhibitor used for flea control and would not be effective. Ivermectin is an anti-parasite drug and would not be effective.

Answer 116

b. Afoxalaner ## Footnote From the list of medications Afoxalaner (Nexguard) is the best choice. This flea medication contains an adulticide; whereas, pyriproxyfen and Lufenuron are only insect growth regulators. Spinosad should never be used with extra-label doses of Ivermectin and is probably why this client discontinued flea medications in the first place. Permethrin is an excellent flea medication, as it is a repellent and adulticide, but it is toxic to cats. Fipronil is toxic to rabbits.

Answer 117

d. Castration ## Footnote Based on the history and ruling out other endocrinopathies this patient likely has hair cycle arrest (Alopecia X). The pathogenesis of this disease is not known. This condition is common in Pomeranians, Chow Chows, Alaskan Malamutes, Toy Poodles, and Samoyeds. The most common clinical signs are truncal alopecia and hyperpigmentation. The treatment of choice (if the dog is intact) is to neuter; however, it is not uncommon to see a relapse in clinical signs 1-2 years after neutering. Melatonin may help new hair to grow if a relapse occurs. Trilostane, mitotane, and growth hormone supplementation have been tried with varying success. Levothyroxine is a thyroid supplement and would not be indicated.

Answer 118

a. You are concerned about a vaccine reaction; biopsy ## Footnote The lesion is highly suggestive of a vaccine reaction; particularly post-rabies vaccination panniculitis (inflammation of the sub-cutaneous) due to location and description of the lesion. Rabies vaccine is often given in the right hind limb. Initially, this condition presents with a nodule where the vaccine occurred and then complete alopecia occurs 1-3 months afterwards. Many times there is a long delay between vaccination and clinical signs (up to 6 months). Lesions usually resolve on their own, but use of pentoxifylline or prednisone can be effective. Definitive diagnosis would require a skin biopsy. An allergic reaction or endocrinopathy is less likely since the lesion is focal. Endocrinopathies usually result in bilaterally symmetrical alopecia. Hair loss due to allergies is usually a result of pruritus, which was not mentioned in the history. This would be an atypical location and lesion for an autoimmune condition.

Answer 119

d. Microscopic examination of macroconidia ## Footnote Proper management of dermatophytosis requires identification of genus and species, which can only be done from microscopic examination of macroconidia. Only about 50% of Microsporum canis strains fluoresce with ultraviolet light (Wood's lamp). Microsporum gypseum and Microsporum canis can both present as white colony growth with a pH change at 5 to 7 days, but require different management strategies. The source of M. gypseum is soil; the ultimate source of M. canis is a potentially asymptomatic cat.

Answer 120

d. Skin scrape ## Footnote Demodex injai typically causes greasy seborrhea, especially on the face and dorsal trunk. Terriers and Shih Tzus may be predisposed. Some dogs may be pruritic. This mite is long and slender when compared with Demodex canis. A diet trial and intradermal skin test may be indicated in the future if the skin scrape is negative. A bacterial culture may be needed if bacteria were seen on cytology. There is no indication to perform a CBC. None of the other tests would be considered part of a dermatological database

Answer 121

d. Hycodan ## Footnote Dermatomyositis is a relatively unusual condition that results in skin lesions as well as myositis. The skin lesions initially appear as papules and vesicles which then rupture, ulcerate, and may progress to crusty alopecic lesions. The myositis sets in a little later and atrophy of the temporalis muscle is often seen. In more severe cases the muscles of the distal extremities become involved and megaesophagus may be observed. Since muscle changes usually lag, other diagnostic tests such as a skin scraping and cytology are performed first to rule out other common conditions. The condition has a variable prognosis as the clinical signs may wax and wane. Medical management usually consists of pentoxifylline, prednisone, and cyclosporine. Prednisone and cyclosporine serve as immunomodulatory medications. Pentoxifylline is used to help improve bloodflow. Hycodan contains hydrocodone and is used as a cough suppressant.

Answer 122

b. Systemic antibiotics for 3-4 weeks and start a diet with a novel protein diet ## Footnote Superficial bacterial infections require antibiotics for at least three weeks. Deep infections require antibiotics for 6-8 weeks. The decision to stop antimicrobial therapy should ideally be based on clinical signs. The general rule is to stop antibiotics 2 weeks after clinical resolution. In practice, this can be difficult because it would require multiple re-checks. Topical therapy with an antimicrobial shampoo can be beneficial, but this infection appears generalized and severe; therefore systemic antibiotic therapy is warranted. As with any bacterial infection there is usually an underlying cause. The logical next step would be to perform a diet trial and rule out food allergy before work-up of environmental allergies. Environmental allergy is a diagnosis of exclusion and flea, food, and contact allergies must be ruled out before a diagnosis of environmental allergies is made. Additionally, intradermal testing cannot determine if a patient has environmental allergies or not, since normal dogs will also test positive. Additionally, this dog most likely has a food allergy based on the age of onset of clinical signs. Food allergy occurs usually before a year of age whereas environmental allergies occur after 9 months to 1 year of age.

Answer 123

d. High-dose dexamethasone suppression test ## Footnote HDDST will suppress cortisol secretion in about 75% of PDH patients 3-6 hours post dexamethasone administration. Cortisol secretion does not become suppressed with dexamethasone administration with adrenal dependent hyperadrenocorticism. If cortisol secretion is suppressed with a HDDST, PDH is diagnosed. If cortisol is not suppressed, there is a 50-50 chance that the hyperadrenocorticism is due to PDH or an adrenal tumor. LDDST will suppress cortisol secretion in approximately 65% of pituitary dependent hyperadrenocorticism patients. The urine cortisol:creatinine ratio measures the significance of urine cortisol concentration and may be increased with both PDH and ADH. Serum cortisol levels may be affected in many different situations such as stress; therefore they are an unreliable indicator of disease. An elevated serum cortisol level will not differentiate between PDH and ADH.

Answer 124

c. Serum sodium and potassium ## Footnote Addisonian patients deficient in mineralocorticoids will usually exhibit the classic findings of hyponatremia and hyperkalemia. Monitoring serum sodium and potassium concentration while treating with exogenous mineralocorticoids is the best way to determine if the level and frequency of dosage is adequate for the patient. An ACTH stimulation test can be used to monitor the efficacy of treatment of a patient with Cushing's disease, but does nothing for an Addisonian.

Answer 125

e. Hypernatremia ## Footnote The classic laboratory finding for an Addisonian includes hyponatremia, hyperkalemia, azotemia, anemia, acidosis, hypoglycemia, and of course a low resting cortisol level or low ACTH stimulation test result.

Answer 126

b. The polyuria and polydipsia are not likely caused by diabetes mellitus. Further diagnostic tests should be pursued to look for the cause of polyuria and polydipsia ## Footnote In a dog with normal kidneys, glucose does not begin to spill into the urine until the blood glucose is around 180 mg/dl. In a cat, glucose does not begin to spill into the urine until the blood glucose reaches between 200-280 mg/dl. Another cause for the PU, PD should be sought in this patient. When the blood glucose is high enough to spill into the urine, the polyuria seen is caused by an osmotic diuresis resulting from the osmotic pull of the glucose in the urine. The kidneys are not refractory to antidiuretic hormone with DM.

Answer 127

b. Initiate therapy with cyclosporine ## Footnote The signalment, history and clinical signs are most consistent with a perianal fistula. Although the pathogenesis is not fully understood, this disease is thought to be primarily immune-mediated. The treatment of choice for perianal fistula is medical management with cyclosporine, as resolution is achieved in greater than 65% of dogs. Surgical correction may lead to fecal incontinence or stricture formation, however surgery for removal of the anal sacs in combination with cyclosporine has recently shown promise. If this was an anal gland abscess, lancing the abscess and drain placement with systemic antimicrobial therapy would be indicated. If you suspected this to be a cancerous process, a minimum database including CBC, chemistry, thoracic radiographs and abdominal ultrasound are recommended for disease staging. The treatment of choice for anal sac adenocarcinoma is surgical resection, followed by adjunct therapy.

Answer 128

a. Immunosuppressive drugs ## Footnote Antibiotics may reduce symptoms temporarily but will not cure perianal fistulas. Surgery used to be the treatment of choice, but it carries a guarded prognosis due to the risk of fecal incontinence. Perianal fistulas are an immune mediated disease, and medical management with immunosuppressive therapy, perhaps with cyclosporine, is now the initial treatment of choice. However, a combination of surgery and immunosuppressive therapy is not uncommon. German shepherds are predisposed to development of perianal fistulas.

Answer 129

a. Immunofluorescent assay on affected epithelium ## Footnote Although the clinical signs are supportive for distemper, the definitive diagnosis is examination of blood or tissue by immunofluorescent assay. This can be performed on tracheal, vaginal, respiratory, or other epithelium. These samples may be negative if the dog is only showing neurologic signs or if a circulating antibody is present. The diagnosis can then be made by serology for distemper IgM or increased CSF to serum virus specific IgG. In addition, a distemper PCR test is now available and is performed on swabs of ocular or nasal discharge. The test can have false positives in some vaccinated animals; however, animals showing signs consistent with distemper that are PCR positive should be considered likely infected with distemper.

Answer 130

c. Campylobacteriosis ## Footnote This is a gram negative motile, thin, S shaped or gull shaped rod. It can occur singly, in pairs or in chains. C. jejuni is most commonly isolated. You can also isolate this organism with fresh fecal swabs streaked onto Campylobacter blood agar plate which grows in an oxygen-reduced atmosphere in 3-4 days. Salmonella is a gram negative bacillus. C. difficile is a gram positive rod. Cryptosporidium is a coccidian parasite. Fun Fact: Kids with puppies are 16 times more likely to acquire campylobacteriosis.

Answer 131

e. Abdominocentesis ## Footnote You should be highly suspicious of leakage at the surgery site and resultant septic peritonitis. The most common time for anastomosis failure is 3-5 days postoperative. This is due to the degradation of fibrin at the site prior to deposition of sufficient collagen. Abdominocentesis would likely reveal a septic inflammatory process, confirming your clinical suspicion with the finding of of intracellular bacteria. A CBC and chemistry are helpful adjunct diagnostic tests but are not specific for septic peritonitis. An abdominal ultrasound would not distinguish between post-operative abdominal fluid and/or free gas and a septic effusion. Serum lactate, although helpful, is also not specific for sepsis. Thoracic radiographs could be useful to assess for less likely complications such as aspiration pneumonia.

Answer 132

b. Total solids of 6.0 ## Footnote HGE is characterized by acute onset of hemorrhagic diarrhea accompanied by marked hemoconcentration. HGE can be due to a hypersensitivity reaction in the intestines or from Clostridium perfringens enterotoxin. It usually affects small dogs such as Miniature Poodles and Miniature Schnauzers. They develop a raspberry jam-like diarrhea, vomiting, and abdominal pain. The key findings are a high PCV of 55-60 and normal total protein that is not as high as would be expected from the degree of hemoconcentration, probably due to protein loss into the intestine.

Answer 133

c. The teeth are brown due to the formation of tertiary dentin, which stains easily ## Footnote Aggressive chewing of things like rocks, tennis balls, cage bars, etc. causes abrasion of dentin. Tertiary dentin, which is produced as a response to the wearing of the teeth, stains easily. Tertiary dentin will usually prevent the exposure of the pulp cavity unless its production cannot keep up with its rapid wear.

Answer 134

a. Maintaining urine specific gravity of \<1.020 ## Footnote An important principle in management of any patient with urolithiasis is to maintain dilute urine so that solutes do not concentrate to the degree that they form precipitates that lead to stone formation. Struvite stones (magnesium ammonium phosphate) tend to form in alkaline urine so ideal urine pH for struvite stone formers is usually around 6.5. Other principles of management are to decrease urea in the urine, often done by moderate protein restriction and to decrease the minerals involved (magnesium and phosphate). Finally, a key element in struvite stone formation is the presence of a urinary tract infection, particularly with urease-producing microbes, most notably staphylococcus and proteus. Monitoring, preventing, and treating UTIs is an important aspect of management of these patients.

Answer 135

b. Both are diffuse changes throughout the lens, but the animals can see through an incomplete cataract. ## Footnote An incomplete cataract is not completely opacified and a tapetal reflection can be seen through it. The animal can see through an incomplete cataract, albeit probably not as clearly as through a normal lens. A complete cataract is a completely opacified lens that cannot be seen through and through which a tapetal reflection cannot be seen. A focal cataract is referred to as an incipient cataract. The normal aging change to the center of the lens is nuclear sclerosis. Degradation of lens proteins after developing a cataract is termed a resorbing cataract.

Answer 136

e. Trauma ## Footnote Traumatic proptosis is very common in brachycephalic breeds and is the lesion in the picture.

Answer 137

a. Schirmer tear test ## Footnote A mucoid ocular discharge is the primary sign of keratoconjunctivitis sicca. A Schirmer tear test measures the amount of aqueous tear film being produced. In KCS, it should measure very low. The Fluorescein dye stain would check for disruption of the corneal layers such as a corneal ulcer. Tonometry would measure the intraocular pressure and look for diseases such as uveitis or glaucoma. The Fundic exam evaluates the retina and optic nerve for abnormalities.

Answer 138

c. Orbital neoplasia ## Footnote These are the typical signs of orbital neoplasia, which is somewhat common in older dogs. Infections are usually accompanied by more systemic signs and localized pain and erythema. Endophthalmitis and intraocular neoplasia would not cause exophthalmos but would manifest with intraocular signs.

Answer 139

b. Progressive Retinal Atrophy (PRA) ## Footnote The correct answer is PRA. Progressive retinal atrophy, sometimes called progressive retinal degeneration is an inherited retinal disease seen in several breeds but most notably Toy and Miniature Poodles. Age of onset is variable, but signs are usually night blindness progressing to complete blindness due to loss of rods prior to cones. Retinal lesions are classically the ones described in this case. It is differentiated from SARDS by the clinical course and the fact that there are no retinal lesions in acute SARDS. You could see similar retinal lesions from glaucoma but would expect more clinical signs and you wouldn't have night blindness progressing. Taurine deficiency causes retinal lesions in cats not dogs, and they have a different appearance.

Answer 140

c. Schirmer tear test ## Footnote This dog has a severe mucoid ocular discharge and corneal changes that are most consistent with keratoconjunctivitis sicca (dry eye). The history of TMS antibiotics is a likely etiology. The diagnostic test of choice for KCS is a Schirmer tear test. The other choices are not specific for the diagnosis of this condition.

Answer 141

c. Lacrimal galnd and gland of the 3rd eyelid ## Footnote KCS comes from a decrease of the aqueous portion of the tear film. This is produced by the lacrimal gland and the gland of the 3rd eyelid. Remember, there are three layers of the tear film. The mucous portion lies against the cornea and keeps the tear film adhered to it. This is made by conjunctival goblet cells. The aqueous portion has nutritional and immunologic factors and is in the middle. It is produced by the lacrimal gland and the gland of the 3rd eyelid. The lipid portion of the tear film is the most outer part, and it allows for even spreading and prevents evaporation of tears. It is produced by the meibomian glands.

Answer 142

a. Flat-line ERG (no response) ## Footnote By definition, an animal with SARDS has a flat-line ERG from day 1 of onset of the condition

Answer 143

a. Decreased outflow of aqueous ## Footnote Glaucoma is an increase in IOP which is dependent on production of aqueous and outflow of aqueous. Clinical increases are always from decreased outflow although treatment can be aimed at either increasing outflow or decreasing production of aqueous.

Answer 144

e. Anterior lens luxation ## Footnote Lens removal is indicated in cases of anterior lens luxation because they usually cause discomfort and usually cause uveitis and glaucoma. Posterior lens luxations are usually innocuous and can be left on the floor of the vitreous cavity. An incipient cataract should only have a minor effect on vision and does not necessitate lens removal. Uveitis and retinal atrophy will not be improved by lens removal. Keep in mind that an argument could be made for removal of the lens in both posterior lens luxation and the cataract; however, the best answer choice is still anterior lens luxation.

Answer 145

b. Hyperadrenocorticism ## Footnote SARDS is frequently seen in middle-aged obese spayed females and often have signs of PU/PD and polyphagia as well as increased liver enzymes and cholesterol. The reason for the association of Cushing's disease and SARDS is poorly understood.

Answer 146

d. Penicillin toxicity ## Footnote In canine patients, the most common cause of KCS is immune mediated. This is why these patients are treated with cyclosporine, a t-cell modulator. Penicillins have not been documented to result in KCS. Sulfonamide containing antibiotics, such as TMS have been shown to cause KCS in some patients. Long-term atropine administration has also been shown to result in KCS. Atropine is a parasympatholytic and will result in decreased tear production. Etodolac has also been associated with KCS in dogs. The corneal pigmentation seen is a nonspecific response to chronic irritation or inflammation. There is also evidence of corneal vascularization which occurs as part of the inflammatory and healing response.

Answer 147

c. Buphthalmos ## Footnote Acute glaucoma can be a very painful condition characterized by epiphora, episcleral injection, corneal edema, and sometimes mydriasis. Buphthalmos, or an enlarged globe, does not usually occur with an acute rise in IOP and is seen more chronically.

Answer 148

d. Doxycycline ## Footnote Doxycycline can result in delayed bone growth and discoloration of the teeth in young growing animals and is thus contraindicated. The other medications listed do not have a direct effect on young growing animals and are safe to administer; however, one must consider the likely pathogen present in the wound, what type of susceptibility pattern it has, as well as the likely penetration of your antibiotic into the area where you want it to exert its effect prior to making a choice.

Answer 149

a. Pradofloxacin is not for use in dogs due to bone marrow suppression ## Footnote Pradofloxacin (Veraflox) is an orally administered, liquid fluoroquinolone antibiotic that was FDA approved in 2012 for use in cats to treat skin infections (wounds and abscesses) caused by Pasteurella multocida, Streptococcus canis, Staphylococcus aureus, Staphylococcus felis, and Staphylococcus pseudointermedius. The drug is not for use in dogs and it has been shown to cause bone marrow suppression resulting in severe thrombocytopenia and neutropenia. Enrofloxacin has been associated with retinal degeneration in cats, particularly at high doses and is used with caution for this reason.

Answer 150

b. Muscle tremors and seizures ## Footnote Early clinical signs associated with lidocaine toxicity include neurological symptoms such as seizures and tremors. Nausea and vomiting may occur, but is usually transient. Cardiovascular and respiratory depression can also occur, but usually later on in the course of clinical signs.

Answer 151

b. Central nervous system depression ## Footnote n dogs, toxicity of lidocaine is manifest primarily as CNS signs. Drowsiness or agitation may progress to muscle twitching and convulsions at higher doses. This occurs before respiratory or cardiac depression. Hypotension may develop if an IV bolus is given too rapidly. Cats are more sensitive to lidocaine toxicity and may show cardiac suppression and CNS excitation.

Answer 152

c. Hypersensitivity reaction ## Footnote Doberman Pinschers are more susceptible to hypersensitivity reactions from sulfa drugs as compared to other breeds. Type III reactions can result in immune complex disease which can cause arthritis, nephritis, and uveitis. Other possible side effects from this class of antibiotics that are not specific to the Doberman include KCS, hepatitis, and blood dyscrasias.

Answer 153

b. Nephrotoxicity ## Footnote Nephrotoxicity is not a reported side effect of azathioprine. All others on this list have been reported as side effects or have been associated with the use of azathioprine. GI upset is the most common of the 4 listed, although it is still relatively infrequent. The other 3 listed side effects are uncommon, but can be life-threatening, so they must be discussed with the owner before starting treatment. Cats are more sensitive to these side effects than dogs because of a deficiency in thiopurine methyltransferase, the enzyme used to metabolize azathioprine. Azathioprine should be used with caution, if at all, in cats.

Answer 154

c. Tetanus antitoxin can cause anaphylaxis ## Footnote The facial contraction and smirk is a characteristic sign of tetanus. Tetanus is caused by the neurotoxin produced by Clostridium tetani. This bacteria enters the body through a wound and begins producing tetanospasmin, a potent neurotoxin that blocks GABA release at the motor end plate and causes sustained muscle contraction. Treatment involves wound debridement, sedation, antibiotics, and minimizing external stimuli as these animals are hyperesthetic. Tetanus antitoxin is given after an initial test dose to monitor for anaphylaxis. Antitoxin prevents further toxin binding but does not affect already bound toxin so it helps decrease progression of clinical signs but will not reverse the signs present. Tick paralysis starts with hind limb weakness which progresses to a stiff forelimb gait and flaccid paralysis. Patients will improve quickly after removal of the tick. Clostridium botulinum causes botulism which is characterized by lower motor neuron paresis/paralysis starting in the pelvic limbs and progressing to quadriplegia. There is decreased muscle tone in all limbs.

Answer 155

d. It can cause cartilage abnormalities in growing puppies ## Footnote Fluoroquinolone antibiotics such as enrofloxacin can cause cartilage formation abnormalities in growing animals. Doxycycline is a tetracycline antibiotic that can cause esophageal stricture formation if it remains in the esophagus for an extended period of time. A small amount of food or water is usually given after the pill to ensure the tablet is not lodged in the esophagus. It can also cause teeth abnormalities in growing animals and often causes GI upset.

Answer 156

d. Give plasma ## Footnote It takes at least a few days for anticoagulant rodenticides to cause prolonged bleeding times and clinical hemorrhage. This could likely be prevented with early intervention with decontamination and Vitamin K1 administration. A plasma transfusion at this stage is unnecessary and should be reserved for patients that have prolonged bleeding times.

Answer 157

b. Increase in total peripheral resistance, increase in cardiac contractility, bronchodilation ## Footnote Epinephrine is an alpha- and beta-adrenergic stimulant which causes peripheral vasoconstriction, increase in total peripheral resistance, increase in cardiac contractility and cardiac output, and bronchodilation. It is often used in cardiac arrests and anaphylactic shock. It is also found in some local anesthetic agents because of its vasoconstrictive effects, which prolongs effect of the anesthetic.

Answer 158

c. Hemolysis ## Footnote Zinc causes a Heinz body anemia and hemolysis.

Answer 159

b. Development of organ mineralization ## Footnote Cholecalciferol (Vitamin D3) acts by becoming converted to calcitriol and increases calcium and phosphorus levels leading to mineralization of organs, especially the kidneys.

Answer 160

d. Diltiazem slows the heart by inhibiting the influx of calcium into the myocardial cells Diltiazem is a calcium channel blocker used to slow the heart to treat supraventricular tachycardias, hypertrophic cardiomyopathy, and hypertension.

Answer 161

d. Mastitis ## Footnote With the recent history of whelping, fever, and a firm, red, painful mammary gland, the most likely diagnosis is mastitis. The puppies should be removed and weaned and warm compresses applied to the gland to promote draining. Antibiotics that penetrate the barrier between the bloodstream and mammary gland should be considered such as trimethoprim-sulfa, clindamycin, and cephalosporins.

Answer 162

c. Normal appearance of proestrus ## Footnote Vulvar swelling and edema occur with rising estrogen levels in proestrus. Bloody vaginal discharge occurs during proestrus due to diapedesis of blood from the engorged endometrium as blood travels through the cervix into the vagina. The bitch is not in estrus based on the lack of receptivity to males.

Answer 163

b. Proestrus and estrus ## Footnote During both of these phases, the female attracts males but she will only stand to be mated during estrus.

Answer 164

c. Enrofloxacin ## Footnote You should be suspicious for prostatitis in this patient. Your antibiotic choice should be based on culture and sensitivity results, but because your patient is sick you will want to start an antibiotic that has good penetration of the prostate until the culture results are back. Chloramphenicol, erythromycin, trimethoprim and fluoroquinolones are able to pass the blood-prostate barrier. Cephalexin and cefpodoxime are cephalosporins and may be effective if the blood-prostate barrier is disrupted, but they would not be the first choice.

Answer 165

d. Estrogen excess ## Footnote This dog's presentation should lead you to the presumptive diagnosis of an estrogen secreting tumor; likely a Sertoli cell tumor or seminoma. The dog was described as cryptorchid; dogs with cryptorchidism are prone to testicular tumors. The signs of male femininization such as gynecomastia and the signs of bone marrow suppression are most suggestive of estrogen toxicity.

Answer 166

b. The specific etiology is still unknown ## Footnote As the name implies, these patients have a mixed population of lymphocytes and plasma cells when biopsied. Many consider the condition to be an idiopathic immune-mediated disorder. PCR studies have been performed in affected patients in search of parainfluenza virus-3, canine adenovirus-2, Bartonella, and Chlamydophila. None of these agents were found to be a potential cause. Typical clinical signs include a history of unilateral or bilateral nasal discharge of several months duration. Large-breed dogs are more often affected and the age may vary.

Answer 167

c. End expiratory thorax ## Footnote An end inspiratory view should be part of any normal thoracic radiograph series. An end-expiratory view is needed to document tracheal collapse in order to demonstrate intrathoracic tracheal narrowing because intrathoracic pressure is highest at end expiration which may worsen intrathoracic airway collapse. Standing lateral views are sometimes used to look for pleural effusion or pneumothorax. Oblique thorax projections are not used.

Answer 168

a. Laryngeal inflammation ## Footnote Seizure is a possible sequela if the cribriform plate is compromised. If this were the case, the complication would likely be fatal. With severe swelling, the administration of corticosteroids and re-intubation is indicated. Sometimes these dogs may need to be intubated for days.

Answer 169

e. Aspiration penumonia ## Footnote Lucy's presentation is typical for a dog with laryngeal paralysis. The arytenoid cartilages fail to abduct during inspiration, resulting in upper airway obstruction. These patients often present with acute clinical signs even though the disease is chronic in nature. Surgical arytenoid lateralization (tie-back) is the treatment of choice but with the chronically opened airway, aspiration pneumonia can be a common side effect. If surgery is not an option, prednisone can be given to help reduce laryngeal inflammation.

Answer 170

d. Oxygen, ampicillin, and enrofloxacin ## Footnote This case and radiograph represent an example of a severe bronchopneumonia. While it would be appropriate to consider more diagnostics, such as a transtracheal wash for cytology and culture, you may have to make a choice without all of that information on your exam. For the information that you do have, aggressive and broad spectrum antimicrobial therapy with ampicillin and enrofloxacin is the best answer, with supportive care with oxygen as needed. Furosemide and oxygen would be the recommended treatments for a dog with congestive heart failure. Sedation and oxygen might be needed for a dog in severe distress from airway obstruction. Corticosteroids would not be an acceptable primary treatment for pneumonia.

Answer 171

c. Tracheal hypoplasia, stenotic nares, and an elongated soft palate ## Footnote Young brachycephalic dogs are often afflicted with a number of upper airway abnormalities collectively termed the brachycephalic airway syndrome. These are tracheal hypoplasia, stenotic nares, elongated soft palate, everted laryngeal saccules, and laryngeal collapse. It is easy to get these confused with tracheal collapse, which affects older toy and miniature dogs. The difference is that tracheal hypoplasia is a congenital narrowing of the trachea (Definition: lumen is less than twice the width of the third rib where they cross on radiographs), and collapsing trachea is an abnormality in the tracheal rings themselves.

Answer 172

e. Dolichocephalic ## Footnote Aspergillus is typically a disease of healthy, apparently immunocompetent dogs that are young to middle-aged. Dolichocephalic breeds are overrepresented. Immunocompromise does predispose to development of disseminated aspergillosis. Being in a large group of dogs does not increase risk, as it is not a contagious disease. Aspergillus is fairly ubiquitous in the environment, and hunting dogs are probably not exposed significantly more than any other dog.

Answer 173

b. The dog probably has aspiration penumonia ## Footnote Aspiration pneumonia is the most likely complication from this type of anesthesia and surgery. Coupled with the radiographic findings, it is the best choice. A pneumothorax from surgery or pneumomediastinum from tracheal tube trauma could both certainly occur but don't quite fit this scenario. If you were wondering how soon you would see respiratory signs from aspiration and radiographic signs, it can be very quickly.

Answer 174

a. Thermal damage to the bronchi ## Footnote Carbon monoxide inhalation is an important component of smoke inhalation morbidity as it leads to carboxyhemoglobin formation and displacement of oxygen. Carbon dioxide inhalation at high levels leads to severe acidosis, which leads to an increase in respiratory rate. Damage to the larynx from the heat causes edema and swelling, contributing to upper airway obstruction. The heat damage does not usually reach the level of the bronchi or lower airways. Smoke also can inhibit pulmonary macrophage function, and skin burns can worsen pulmonary status.

Answer 175

d. Bordetella bronchiseptica ## Footnote Although not common, Bordetella infections can develop into a primary pneumonia, particularly if the dog has a weakened immune system. Mycoplasma pneumoniae is a bacteria that can cause a primary pneumonia in humans, but it is not known to be a problem in dogs. The other choices require an underlying problem such as aspiration, foreign body, viral infection, neoplasia, etc. to be present in order to create an infection. Secondary bacterial infections can be extremely severe and need to be diagnosed and treated appropriately and aggressively.

Answer 176

b. Tpical antifungal therapy (i.e. Clotrimazole) ## Footnote Topical antifungal therapy is considered more efficacious and less costly than long-term systemic antifungal therapy. Corticosteroids would be contraindicated. Surgery and antibiotics would not be successful in controlling a fungal infection. The currently recognized treatment of choice is clotrimazole, a synthetic imidazole that has an 80% cure rate with single administration. The main potential complication is CNS exposure to the drug if there has been erosion of the cribriform plate.

Answer 177

c. Blastomycosis (Blastomyces dermatiditis) ## Footnote These findings are most consistent with blastomycosis. Lymphoma would be a great differential but is less consistent with the nodular lung pattern and suppurative inflammation in the lymph node. Plague is an interesting differential for the lymphadenopathy and cytology findings but is not consistent with the lung pattern or history. This Weimaraner's disease is too severe to be explained by kennel cough alone. While this diagnosis is sometimes made easy by visualization of organisms in aspirates or skin scrapings, it is not always seen as in this case. Remember, Blastomyces is seen as a broad-based budding yeast. The next step to obtain a definitive diagnosis in this patient would be a transtracheal wash or bronchoalveolar lavage.

Answer 178

a. Central nervous system on the right ## Footnote This dog has paradoxical vestibular disease. This disease is usually caused by a destructive lesion in the CNS in which there is loss of inhibition of the vestibular output on the side of the lesion. There is therefore a relative increase in vestibular output on the side of the lesion, causing vestibular signs on the side opposite the lesion (yes, this can be confusing). In this case, the right sided lesion has vestibular signs that would normally localize the lesion to the left side. When the lesion causes vestibular signs and proprioceptive deficits, the lesion is ipsilateral to the side with the proprioceptive deficits.

Answer 179

e. Chlorhexidine ## Footnote The key here is to recognize that the question is asking about peripheral vestibular disease; otherwise, metronidazole would be a good choice as a cause of central vestibular disease. Chlorhexadine is a topical drug implicated in ototoxicity and peripheral vestibular disease. Another excellent choice would be aminoglycosides including neomycin, kanamycin, tobramycin, amikacin and gentamicin.

Answer 180

a. Strict cage rest ## Footnote By far, the most likely diagnosis is intervertebral disc disease (IVDD) based on the history and myelogram showing a collapsed intervertebral space at T12-13 and an extradural compressive lesion originating from the same site. IVDD can be managed by surgical decompression or non-surgically. The most important aspect of non-surgical management of IVDD is STRICT cage rest, usually for a full 8 weeks. Exercise should be avoided during the period of cage rest. Steroids, analgesics, and/or muscle relaxants may be useful additions to the management of these dogs.

Answer 181

d. Cervical spondylopathy ## Footnote The signalment and clinical signs are most helpful in answering this question. Doberman Pinschers, Great Danes, and Thoroughbred horses are predisposed to cervical spondylopathy, which is a cervical vertebra malformation that causes cervical myelopathy in dogs and horses. The malformation is usually stenosis or wedging of the vertebral canal, vertebral malalignment, or vertebral instability. This disease usually manifests as ataxia and paresis of all four limbs and UMN signs of all four limbs

Answer 182

d. Neospora caninum ## Footnote The definitive host is the dog (or coyote or other canidae) which aquires the infection by eating infected meat, and spreads it to cows by shedding oocysts in the pasture or feed. Although clinical signs are mainly seen as abortions and abnormal calves in herbivores, dogs may suffer from neurologic and muscular abnormalities. Infection to other dogs is usually as a result of transplacental spread. IFA is usually performed to make the diagnosis.

Answer 183

b. Subarachnoid space ## Footnote A myelogram is a positive-contrast radiographic study where a contrast agent such as iohexol or iopamidol is injected into the subarachnoid space where CSF accumulates.

Answer 184

a. The dog suffered a brachial plexus avulsion and will most likely need to have the leg amputated ## Footnote Dogs that are hit by cars or who jump out of moving cars often suffer brachial plexus avulsions. Complete nerve root avulsions are not treatable and usually require amputation of affected limbs. Partial avulsions carry a better prognosis but require large amounts of time and physical therapy before seeing any improvement. The lack of deep pain and motor function in the limb is a negative prognostic indicator supporting the diagnosis of a complete brachial plexus avulsion.

Answer 185

d. Rabies If it sounds like it could be rabies, diagnose it until proven otherwise. The signs to focus on are attacked by a wild animal, a behavior change, and a voice change. This should put rabies at the top of your list. This dog is exhibiting signs of the prodromal stage of rabies. Canine distemper is a potential differential, but you will most likely see other symptoms such as respiratory and GI signs. Tetanus will manifest itself as rigidity and botulism as flaccid paralysis. Remember that any animal with an acute behavioral change or flaccid paralysis is a rabies suspect.

Answer 186

d. High PaO2 ## Footnote PaCO2, blood pressure, PaO2, cerebral metabolism, and certain drugs can affect cerebral blood volume and intracranial pressure. In head trauma patients, you want to prevent an increase in intracranial pressure by keeping cerebral blood flow relatively low without causing hypoxia. To keep cerebral blood flow in the low-normal range, the cerebral metabolic rate and PaCO2 should be kept low. Factors that would cause the cerebral metabolic rate to go up include fever, seizures, pain, etc. Mean arterial pressure should be maintained in the normal range to prevent hypotension, hypoxia, and cerebral ischemia.

Answer 187

c. Lesion of the facial nerve can cause vestibular signs ## Footnote While conditions such as otitis media can be seen concomitant to facial nerve and vestibular signs, this occurs due to effects on CN VIII (auditory-vestibular nerve), not CN VII. Otitis media often causes deficits in CN VIII and CN VII since the two nerves run adjacent to each other through the middle ear. The major petrosal branch of the facial nerve innervates the lacrimal and nasal mucosa glands. The chorda tympani nerve, which branches off CN VII, is responsible for taste in the rostral 2/3 of the tongue.

Answer 188

b. Pyridostigmine ## Footnote The important thing to do in this case is to both read the question carefully and view the radiograph in concert with each other. This dog has signs and findings that are most consistent with myasthenia gravis and resultant megaesophagus. Accordingly, pyridostigmine, which is an acetylcholinesterase inhibitor (anticholinesterase), is the best answer choice. If you chose sucralfate because you saw the megaesophagus and thought the dog must have esophagitis, your thinking was accurate but you ignored the dog's clinical signs of weakness. If this dog had presented for regurgitation, that would have been a more appropriate course of action. Acquired myasthenia gravis can also be treated with systemic corticosteroids to decrease immune attack of acetylcholine receptors, but inhaled fluticasone would not do the trick. Enalapril and NSAIDs are not indicated in this patient.

Answer 189

c. Non-steroidal anti-inflammatory therapy and strict rest ## Footnote The most recent literature shows that 50% of dogs with clinical signs of intervertebral disc disease will improve with medical management alone. Medical management involves restricted activity and anti-inflammatory therapy. Prednisone, methyl-prednisolone sodium succinate, and non-steroidal anti-inflammatories are commonly used. Prednisone, if used, should be prescribed at an anti-inflammatory dose and not immunosuppressive. Dexamethasone sodium phosphate has only been shown to increase the likelihood of side effects and complications such as urinary tract infection and is therefore not recommended.

Answer 190

b. Discontinue meloxicam. Start an oral opioid-based pain medication for 5 days. Then start an anti-inflammatory dose of a steroid. ## Footnote This dog has the classic two-engine gait characteristic of Wobbler's syndrome. The hematochezia noted on rectal exam, and the history of a tarry stool (suggesting upper GI bleeding) is likely due to the meloxicam which should be discontinued immediately. Medical management for Wobbler's syndrome involves an anti-inflammatory dose of a steroid. There is a three to five day wash out period needed after stopping meloxicam and before starting prednisone. Further diagnostics for Wobbler's syndrome involves imaging (cervical radiographs, myelogram, MRI or CT) and it can be helpful in ruling out neoplasia or traumatic injuries. The left forelimb lameness and abducted stance are likely due to a pinched nerve however further imaging would be needed for confirmation.

Answer 191

b. Right cerebellum ## Footnote This dog has a left head tilt by definition because his left ear is closer to the ground. The key to answering this question is seeing the left head tilt and reading that the question asks about PARADOXICAL vestibular disease. Vestibular disease can be peripheral or central, and central vestibular disease can be classic in appearance or paradoxical. Peripheral vestibular disease is due to a lesion in the inner ear or vestibular portion of cranial nerve VIII. Classic central vestibular disease is due to a lesion in the brainstem or cerebellum. Signs with peripheral and classic central vestibular disease include head tilt, falling, and circling to the same side as the lesion with nystagmus with fast phase to the opposite side. With paradoxical vestibular disease, the lesion is in certain regions of the cerebellum (flocculonodular lobe) or caudal cerebellar peduncle and produces signs to the opposite sides from which is seen with peripheral and classic central disease.

Answer 192

b. Tensilon response test ## Footnote The correct answer is a Tensilon (edrophonium) response test. Hopefully, you were able to identify the mass in the cranial mediastinum on the chest radiograph, as this was one of the keys to this case. This, in conjunction with the dog's other signs, are suggestive that this dog has a thymoma and associated secondary myasthenia gravis. Tensilon (edrophonium) is a rapidly acting anticholinesterase that reverses signs of myasthenia within minutes in most dogs. A chest CT would be a valid test to confirm the presence of the mediastinal mass and might be an appropriate test before surgery but would not bring you closer to a diagnosis if you already have identified the mass. An MRI of the brain would assess a CNS cause of the dog's signs, which are unlikely, given the other findings. Similarly, a myelogram would assess if a spinal cord lesion caused the dog's signs, but the rest of the findings in this case should point you in a different direction.

Answer 193

a. Urine culture ## Footnote The diagnosis you should have in mind is discospondylitis. Be sure not to confuse this with spondylosis, which is typically not clinically significant and can be expected in most older dogs. The radiographic description is relatively specific for this condition. Neoplasia in the spine should be lower on your differential list because it typically does not cross joints. Disc herniation cannot be ruled out, and advanced imaging would be necessary to know for certain, but given the exam and radiographic findings, discospondylitis should be your top differential. Discospondylitis is usually bacterial in origin, with Staphylococcus being the most common organism involved. Other organisms identified include Brucella canis, E. coli, Pasteurella, Aspergillus, and Streptococcus. In an attempt to identify the causative agent, urine and blood cultures should be considered. The other answer choices are not as high yield in identifying the specific bacterial cause or underlying etiology.

Answer 194

d. Sedation ## Footnote Possible side effects of KBr therapy include polyphagia, polyuria and polydipsia, ataxia, skin reactions, pancreatitis, and vomiting. However, sedation is more likely to occur than these.

Answer 195

c. Enalapril ## Footnote The correct answer is enalapril. All others would be contraindicated. Enalapril is an ACE-inhibitor, which blunts the adverse effects of the renin-agiotensin-aldosterone system thereby reducing sodium and fluid retention. Additionally, ACE-inhibitors cause mild vasodilation by preventing the production of angiotensin-II, which reduces ventricular afterload. Lastly, enalapril and other ACE-inhibitors are protective to cardiac muscle by blunting aldosterone and other hormones which induce cardiac remodeling.

Answer 196

a. Echocardiogram ## Footnote The breed, clinical history of syncope, radiographic findings, and auscultation findings are most consistent with aortic stenosis. Echocardiography would be the best method for diagnosing the disease in which you would find left ventricular concentric hypertrophy, stenosis of the aortic outflow tract, and post-stenotic dilatation of the ascending aorta. A Holter monitor is the test of choice for arrhythmogenic right ventricular cardiomyopathy (ARVC) which is also seen in Boxers and causes syncope but does not fit with the physical exam or radiographic findings. Also called Boxer cardiomyopathy, ARVC is a disease associated with fibrofatty infiltrate into the right ventricle resulting in electrical conduction disturbances and resultant VPCs. A CT scan would not add more information, and cardiac motion typically causes resolution problems on thoracic CT scans. The signs are not consistent with heartworm, which is primarily a right heart problem, or with hemolytic anemia, which a Coombs' test might be useful for.

Answer 197

d. Severe generalized cardiomegaly on thoracic radiography ## Footnote Tetralogy of Fallot is a congenital defect of the heart which includes pulmonic stenosis, dextro-positioned aorta (over-riding), right ventricular hypertrophy, and a ventricular septal defect. It causes shunting of venous blood across the VSD into the arterial circulation which leads to hypoxemia, and an increased drive for erythropoiesis causing polycythemia. Affected animals tend be underdeveloped in size and have a history of exercise intolerance, dyspnea, tachypnea, or syncope due to hypoxemia. Thoracic radiographs usually show a normal to mildly enlarged cardiac silhouette with right ventricular enlargement and pulmonary hypoperfusion due to the shunting of venous blood into the arterial circulation.

Answer 198

a. Atrial septal defect with systemic hypertension ## Footnote This dog's polycythemia developed due to shunting of venous blood into the arterial circulation (aka right-to-left shunting) leading to hypoxemia and an increased drive for erythropoiesis and secondary polycythemia. This can be caused by any of the other 3 answer choices. An atrial septal defect with systemic hypertension results in oxygenated blood shunting into the venous circulation or left-to-right shunting, which usually does not cause hypoxemia.

Answer 199

e. Right ventricular enlargement ## Footnote Right ventricular enlargement is consistent with a right to left shunting PDA. A continuous, or "machinery" murmur is characteristic of a PDA. Bounding or "waterhammer" arterial pulses are common due to the increased systolic pressure and decreased diastolic blood pressure (widened pulse pressure). An aneurysmal bulge is often seen on the dorso-ventral view of thoracic radiographs. Left chamber enlargement occurs with left-to-right shunting PDAs which can often be detected as increased amplitude of the QRS complex on ECG.

Answer 200

a. Bartonella sp. ## Footnote The most commonly reported organisms recovered in animals with endocarditis include Staphylococcus aureus, Streptococcus sp., Corynebacterium sp., Pseudomonas aeruginosa, Erysipelothrix, E. coli, and Bartonella sp.

Answer 201

a. Dilated cardiomyopathy ## Footnote Although taurine deficiency is rare nowadays, it has been associated with DCM in cats and some dogs (English Cocker Spaniels). Commercial cat and dog foods now contain acceptable levels of taurine. In cats, retinal dysplasia also occurs with taurine deficiency.

Answer 202

c. Mexiletine ## Footnote The Holter ECG shows a couplet of ventricular premature complexes. If frequent ventricular ectopy is seen, particularly with runs or R-on-T episodes, treatment is advised with oral ventricular antiarrhythmics. Mexiletine is an oral class I antiarrhythmic that is well-tolerated in dogs. Pimobendan improves systolic function, but does not treat arrhythmias. Amlodipine is a calcium channel blocker used for patients with systemic hypertension. Diltiazem is used for supraventricular tachycardias to slow conduction down the AV node. Furosemide is a diuretic used in the treatment of heart failure, it does not have antiarrhythmic properties.

Answer 203

c. This arrhythmia is often secondary to hyperkalemia ## Footnote The rhythm diagnosis is third degree (complete) AV block. Atropine is often administered in attempts to increase the ventricular rate in these patients but almost never significantly increases the heart rate. The cause of complete AV block is normally unknown, but is rarely improved with medical management or time, thus typically necessitating an artificial pacemaker. Intravenous lidocaine is ABSOLUTELY contraindicated in these patients since this may abolish the ventricular escape rhythm. Though atrial standstill may be secondary to hyperkalemia, this rhythm is clearly not an atrial standstill since there are P-waves evident (hence atrial depolarization).

Answer 204

a. Furosemide and enalapril ## Footnote The radiograph here shows a severe symmetrical alveolar pattern in the perihilar region extending to the right and left caudal lung lobes. The heart is tall on the lateral view causing dorsal elevation of the trachea. This, in conjunction with the physical findings, is compatible with left congestive heart failure (CHF) secondary to mitral valve regurgitation. The dog also has hepatic congestion evident by enlargement on the radiograph. Treatment for CHF include diuretics (furosemide/Lasix, hydrochlorothiazide, spironolactone), arterial vasodilators (enalapril, benazepril, amlodipine, hydralazine), positive inotropes (pimobendan), and venodilators (nitroglycerine). Clavamox and enrofloxacin are antibiotics which could be used to treat pneumonia, but that is not this dog's problem. Immiticide is the treatment for heartworm. Atenolol is a beta blocker and not part of the management of mitral regurgitation or CHF. Atropine or a pacemaker would be indicated for conduction problems.

Answer 205

e. Left ventricular hypertrophy ## Footnote The left heart is not affected by pulmonic stenosis. Concentric hypertrophy occurs in the right ventricle as a result of the increase in pressure in the right heart caused by the increase in resistance to the ejection of blood through a stenotic pulmonary outflow tract. The post-stenotic dilation develops as a result of turbulent blood flow.

Answer 206

a. Mitral valve dysplasia ## Footnote This abnormality is a congenital anomaly of the mitral valve. The valve leaflets may be thickened, fused, fibrosed, etc. The chordae tendinae or the papillary muscles attaching to the mitral valve may be irregular as well. German Shepherd Dogs, Great Danes, and other large breed dogs are predisposed to this disease. Myxomatous mitral valve degeneration occurs in older dogs, but would otherwise result in similar physical exam and radiographic findings as those described. Tricuspid dysplasia results in an enlarged right heart, and the murmur would be heard best on the right side of the dog. Aortic stenosis results in concentric hypertrophy of the left heart, which may or may not be detectable on radiographs. Also, the murmur is heard best at the left heart base with aortic stenosis.

Answer 207

d. Electrical alternans and pulsus paradoxus ## Footnote Electrical alternans is an ECG finding in which the height of QRS complexes alternate due to the physical swinging of the heart as it contracts within the pericardial effusion. Pulsus paradoxus is an exaggerated decrease in arterial pulse quality during inspiration caused by increased right-sided filling at the expense of reduced left ventricular filling because the heart is constrained by the pericardial effusion. Third degree AV block does not occur with pericardial effusion. Obscuring of the cardiac/pulmonary parenchyma interface is usually due to pulmonary parenchyma changes or pleural effusion. Weak pulses and hepatomegaly are not specific to pericardial effusion, though are often present in dogs with severe pericardial effusion. Waterhammer pulses are palpated with PDAs or severe aortic regurgitation.

Answer 208

d. Tricuspid dysplasia ## Footnote Tricuspid dysplasia is similar to mitral valve dysplasia in the irregular valve leaflets, chordae tendinae, or papillary muscles of the valve. Labrador Retrievers, German Shepherd Dogs, and other large breed males are predisposed to the disease. Signs of right heart failure, such as ascites and hepatomegaly occur in advanced disease. The prognosis for these animals is guarded to poor depending on the severity of the regurgitation. Pulmonic stenosis causes a pressure overload of the right heart and causes concentric hypertrophy, which may or may not be detectable by radiography. The murmur with PS is heard better at the left heart base. Hemangiosarcoma and hepatocellular carcinoma are less likely in a 7 month old puppy.

Answer 209

a. No anti-arrhythmic therapy is necessary at this time ## Footnote There are several general guidelines/recommendations regarding treatment of ventricular premature contractions which is what is shown on the ECG strip. These include a heart rate of over 180 bpm, pulse deficits, clinical signs, and VPCs for over 20 seconds in duration. In this case, the heart rate is visible on the recording and clearly not elevated. The patient's physical exam findings are not suggestive of an immediate problem secondary to the arrhythmia. There are many dogs with intermittent VPCs that are not of clinical importance. However, it is recommended that the patient be evaluated regularly and ideally have a consultation with a cardiologist to ensure the progression of heart disease is being minimized. Furosemide is not indicated as there is not an indication that the patient is fluid overloaded or in fulminant heart failure. Mexiletine is a Class IB anti-arrhythmic and is not necessary given the lack of severity in the ECG findings.

Answer 210

d. Pericardiocentesis ## Footnote This radiograph and case are a good example of pericardial effusion with the classic finding of a markedly enlarged heart with a globoid shape. The most common type of effusion by far is hemorrhage which can be idiopathic or from neoplasia such as hemangiosarcoma. Based on this finding, in conjunction with the dog's tachycardia, a pericardial tap for both diagnostic and therapeutic purposes is indicated. Furosemide is contraindicated in cases of pericardial effusion because it will decrease preload in the right side of the heart and can promote circulatory failure. Melarsomine is the treatment for heartworm. Antibiotics are very unlikely to help this dog unless the effusion is from some sort of infectious pericarditis, which would be extremely unusual in dogs.

Answer 211

c. 20cm H2O ## Footnote Pressures above 20cm H20 may result in barotrauma. In an otherwise healthy patient it is not recommended to exceed this pressure. In patients with chronic atelectasis, anesthetists will be much more apprehensive about over ventilating or ventilating the lungs too quickly, as acute expansion can trigger re-expansion pulmonary edema, which may then lead to acute respiratory distress syndrome and death.

Answer 212

c. Desflurane ## Footnote Speed of action of inhalant anesthetics is most directly related to blood-gas solubility. Desflurane has the lowest solubility and therefore, has the fastest time of action. In order from fastest to slowest, the inhalants are (desflurane, NO, sevoflurane, isoflurane, enflurane, halothane, diethyl ether, methoxyflurane).

Answer 213

d. Bradycardia and hypertension ## Footnote In order to perfuse the brain when there is increased ICP, the body needs to increase systemic blood pressure to overcome that pressure. This occurs primarily through reflex vasoconstriction. The increase in blood pressure leads to decreased heart rate. Therefore, Cushing's reflex is when increased ICP leads to hypertension and bradycardia.

Answer 214

a. Isoflurane gas and injectable succinylcholine ## Footnote To control all respiratory motion without pushing a dog to an excessive and dangerous plane of anesthesia, a neuromuscular blocking agent would be necessary. You would never use one of these alone for a surgical procedure as they do not provide analgesia or reduce consciousness, which is why an inhalant gas anesthetic is also used to maintain anesthesia in this case. Options include succinylcholine which is a depolarizing neuromuscular blocker or one of the nondepolarizing neuromuscular blocking agents such as pancuronium, d-tubocurarine, and atracurium. Edrophonium is a cholinesterase inhibitor which can be used to reverse neuromuscular blockers. Fentanyl is an opioid and is actually an excellent choice to provide pain control and decrease the concentration of gas anesthetic needed in a procedure such as this one, but it would not accomplish the goal of preventing all motion, including respiration when necessary.

Answer 215

b. It is nearly always type 1 (insulin-dependent) ## Footnote Diabetes mellitus in dogs is nearly always insulin-dependent diabetes caused by immune destruction of beta cells of the pancreas. Cats get type 1-like diabetes (insulin-dependent) about 20% of the time and type 2-like diabetes (non insulin-dependent) about 80% of the time

Answer 216

c. Diabetes mellitus ## Footnote Diabetes frequently results in bilateral cataracts within 6-12 months of diagnosis but should not cause hyphema.

Answer 217

c. Tricuspid valve insufficiency ## Footnote While mitral insufficiency can and does lead to pulmonary hypertension, tricuspid insufficiency does not. Altitude causes pulmonary hypertension by leading to vasoconstriction. Heartworm is probably the most common cause of pulmonary hypertension.

Answer 218

c. Knott's negative, antigen positive ## Footnote The definition of an occult heartworm infection means that no microfilaria are circulating; therefore, a Knott's test will be negative. This can occur when there is a single sex infection (female), only immature adult worms are present, the immune system cleared the microfilariae, or the animal is on a treatment that clears microfilariae. In dogs, the heartworm antigen test is sensitive and should be positive most of the time; however, it may occasionally have false negatives.

Answer 219

b. Peripheral nerve sheath tumor ## Footnote Soft tissue sarcomas include a group of mesenchymal tumors with similar biologic behavior, namely a locally invasive growth pattern and a metastatic rate of less than 20% for low- and intermediate-grade tumors. High-grade tumors have up to a 50% metastatic rate. These tumors include peripheral nerve sheath tumors (PNST), hemangiopericytomas (HPC), fibrosarcomas (FSA), liposarcomas, malignant fibrous histiocytomas, myxosarcomas, rhabdomyosarcomas, and leiomyosarcomas. Hemangiosarcoma and osteosarcoma are mesenchymal in origin but are not lumped into this category due to their highly metastatic behavior. Histiocytic sarcoma and mast cell tumors are considered of round cell origin. Basal cell tumors are epithelial in origin.

Answer 220

d. The dog should be treated for fleas and tapeworms ## Footnote Fleas are a required intermediate host of Dipylidium caninum. Dogs become infected by swallowing fleas that carry the tapeworm eggs. Finding proglottids of this tapeworm in the feces or perianally indicates the presence of fleas on the dog.

Answer 221

a. Rickettsia rickettsii The correct answer is Rickettsia rickettsii.

Answer 222

d. Topical administration of imidacloprid and permethrin ## Footnote Based on the signalment, history, and physical findings, you should be most suspicious of flea allergy dermatitis (FAD). FAD can occur in any aged dog but typically dogs over 6 months of age. Unlike canine atopy and food allergies which usually have a gradual onset of pruritic signs, FAD can have a rapid onset, as described in this case. Additionally, the distribution and description of the lesions over the caudal half of the body are classic for canine FAD. The most common sites affected for atopy or food allergy are the face, paws, distal extremities, ears, and ventrum. There are many treatment options for FAD including: Imidacloprid (Advantage), also available with 44% permethrin as "Advantix". Fipronil & S-Methoprene (Frontline Plus) Selamectin (Revolution) Nitenpyram (Capstar) Lufenuron (Program), also available with milbemycin as (Sentinel) Spinosad (Comfortis) Dinotefuran, Permethrin & Pyriproxifen (Vectra 3D) Afoxolaner (Nexgard) In addition to insecticidal treatments, flea allergy sometimes needs to be treated with anti-pruritic or antibiotic drugs to address secondary infection; however, the question is specifically asking for treatment of the primary underlying etiology, which, in this case, is the presence of fleas. Hyposensitization injections would be the treatment for atopic dermatitis. A dietary change would be appropriate for food allergy. Antibiotics would be appropriate for a primary pyoderma. Cyclosporine is an adjunct therapy used in atopic dogs.

Answer 223

d. Staphylococcus pseudintermedius (Staphylococcus intermedius) ## Footnote Intracytoplasmic cocci from a dog's skin are most likely Staphylococcus pseudintermedius (formerly called Staphylococcus intermedius), which is the species host-adapted to canines. Staphylococcus hyicus is host-adapted to pigs, so is less likely to be isolated from a dog. Malassezia (yeast) organisms are much larger than cocci and are not observed within the cytoplasm of neutrophils.

Answer 224

b. ACTH stimulation test ## Footnote The chemistry profile above is highly suggestive of hypoadrenocorticism. An ACTH stimulation test would give a definitive diagnosis for Addison's disease if the plasma cortisol concentration is low after ACTH administration. A bile acids test is not indicated since liver function is not in question. Thoracic radiographs may show microcardia, hypoperfused lungs, and rarely megaesophagus. ECG abnormalities would be consistent with hyperkalemia, which includes wide, flat, or absent P waves, widened QRS complexes, tall spiking T waves, and bradycardia.

Answer 225

b. Diabetes mellitus Post-operative complications for insulinoma removal may include acute pancreatitis, transient diabetes mellitus, and recurring hypoglycemia (indicative of metastasis). The other options listed are not documented to occur as a result of removing part of the pancreas.

Answer 226

c. Methylaxnthines ## Footnote The correct answer is methylxanthines. Specifically theobromine and caffeine are the toxic compounds.

Answer 227

c. Nephrotoxicity Nephrotoxicity is seen when using Amphotericin B. About 7% of dogs using Itraconazole will develop ulcerative skin lesions when used at a higher dosage rate.

Answer 228

d. Spherule The correct answer is spherule. The diagnostic stage of Coccidioides immitis is the spherule. This is a 20-200 micrometer round, double-walled structure containing many endospores. As a reminder, the broad-based budding yeast is Blastomyces. The small yeast with large capsule is Cryptococcus, and the branching fungal hypha is Aspergillus. The small intracellular yeast is Histoplasma.

Answer 229

a. Acepromazine Acepromazine causes marked splenic dilation with blood and a corresponding decrease in hematocrit concentration.

Answer 230

e. Perform a left sided thoracocentesis on the dorsal aspect of the chestThis is a classic radiograph of a left sided pneumothorax. This case provides the advantage of having a "normal" right side. Notice the lungs are collapsed on the left and no vasculature or airways can be appreciated on the left as compared to the right. In a standing patient it is best to perform a thoracocentesis dorsally since air rises. This will yield the most amount of air to aspirate. In most cases with a pneumothorax secondary to trauma it is not necessary to place a chest tube as the leak seals over quickly, making a chest tube excessive; however, patients that are tapped must be monitored closely for recurrence of pneumothorax. If air build up persists more aggressive treatment such as a chest tube with or without continuous suction should be considered.

Answer 231

d. 400 mL ## Footnote To raise the PCV 1% you need to give 2ml/kg of fresh whole blood. So, 40 ml will raise the dog's PCV by 1%, but since we need to raise it by 10%, you will need 400ml or fresh whole blood.

Answer 232

c. Cardiotoxicity ## Footnote In addition to the usual side effects of chemotherapeutic drugs such as myelosuppression and GI side effects, a major concern with adriamycin administration is dose dependent cardiotoxicity. The drug that causes ileus is vincristine. The drug that causes anaphylaxis is L-asparaginase. The drug that causes nephrotoxicity is cisplatin. The drug that causes cystitis is cyclophosphamide.

Answer 233

d. Finding Giardia cysts on fecal sedimentation ## Footnote Giardia trophozoites or cysts can be found on a direct fecal smear. Giardia cysts can be found on fecal flotation. The organism can also be detected by FA and ELISA.

Answer 234

c. Demodex mites are commensal organisms that can be found in skin without clinical signs ## Footnote The correct answer is demodex mites are commensal organisms that can be found in skin without clinical signs. Focal demodex lesions will usually resolve spontaneously without any treatment. Demodex are found down at the hair follicle, so diagnosis is made by a deep skin scraping. The most commonly affected areas on a dog include the face, muzzle, periorbital region, and thoracic limbs.

Answer 235

c. A Babesia infection ## Footnote The correct answer is a Babesia infection. The pyriform structures in the RBCs reveal the diagnosis. Leukocytozoon only occurs in birds.

Answer 236

b. Triple pelvic osteotomy ## Footnote The correct answer is triple pelvic osteotomy. Triple pelvic osteotomy should only be performed in young dogs (less than a year old) that have minimal secondary degenerative changes and deep acetabulums. NSAIDs are often used to medically manage patients with dysplastic hips. A total hip replacement is a treatment option for dogs that are not benefiting from medical therapy. An FHO is a salvage procedure for those in which either a TPO or total hip replacement is not an option.

Answer 237

d. Lyme disease ## Footnote The correct answer is Lyme disease, which is caused by Borrelia burgdorferi. This classic cutaneous rash does not appear to occur in dogs. Instead you see signs of arthritis, lymphadenopathy, fever, and anorexia about 2-5 months after exposure.

Answer 238

c. Hypothyroidism ## Footnote Myxedema, an increased amount of mucin and other ground substances in the dermis, can be a marker for hypothyroidism. Other endocrinopathies that can be associated with myxedema include excesses of growth hormone such as acromegaly.

Answer 239

a. Mandibular prognathism The correct answer is mandibular prognathism. Mandibular prognathism (mandible longer than maxilla) and maxillary brachygnathism (maxilla shorter than mandible) is a common anatomic feature of brachycephalic dogs. This malocclusion syndrome is also known as an "undershot" occlusion or an underbite.

Answer 240

a. Pacemaker implantation ## Footnote The correct answer is pacemaker implantation. The rhythm is complete heart block (also known as 3rd degree AV block). There is no consistent PR interval; the ventricular beats are escape beats. Atropine can be considered, but is typically not effective in 3rd degree AV block. The only way to restore a normal heart rate in this patient is by implanting a pacemaker, which will require referral to a cardiologist. Sotalol is a ventricular antiarrhythmic, which would actually be dangerous in this patient because it may suppress the ventricular escape focus. Furosemide and doxycycline will not prove beneficial for this rhythm disturbance.

Answer 241

c. Isoflurane gas and injectable succinylcholine ## Footnote To control all respiratory motion without pushing a dog to an excessive and dangerous plane of anesthesia, a neuromuscular blocking agent would be necessary. You would never use one of these alone for a surgical procedure as they do not provide analgesia or reduce consciousness, which is why an inhalant gas anesthetic is also used to maintain anesthesia in this case. Options include succinylcholine which is a depolarizing neuromuscular blocker or one of the nondepolarizing neuromuscular blocking agents such as pancuronium, d-tubocurarine, and atracurium. Edrophonium is a cholinesterase inhibitor which can be used to reverse neuromuscular blockers. Fentanyl is an opioid and is actually an excellent choice to provide pain control and decrease the concentration of gas anesthetic needed in a procedure such as this one, but it would not accomplish the goal of preventing all motion, including respiration when necessary.

Answer 242

b. Persistent right aortic arch ## Footnote The correct answer is persistent right aortic arch. This vascular ring anomaly is an inherited defect that causes a constricting obstruction of the esophagus at the level of the heart base. There is a breed predilection for German Shepherd Dogs and Irish Setters. Clinical signs of regurgitation usually manifest as the puppy is weaned off of milk and onto solid foods. PDAs, pulmonic stenosis, and diaphragmatic hernias of the small intestines should not cause regurgitation; however, vomiting may be a clinical sign if there is an obstruction associated with the diaphragmatic hernia of the small intestine.

Answer 243

a. Melanoma ## Footnote The correct answer is melanoma. Melanoma comprises about 1/3 of all oral tumors in dogs. Many oral melanomas may be amelanotic, as the one in the photograph appears to be. The second most common tumor is squamous cell carcinoma followed by fibrosarcoma and acanthomatous epulis.

Answer 244

e. Hypogastric nerve ## Footnote The correct answer is hypogastric nerve. The pudendal nerve is innervated by the somatic nervous system and the pelvic nerve has parasympathetic innervation to the bladder. The pelvic nerve also gives branches to the descending colon and erectile tissue of the penis or clitoris. The pudendal nerve also gives branches and becomes the perineal nerve along with providing innervation to the external genital organs. The sciatic and obturator nerves do not innervate the bladder. The sciatic nerve is the largest nerve in the body and comes off of L6, L7, and S1. This nerve has two main branches the tibial and common peroneal nerves. The obturator nerve arises from L4, L5, and L6. It is responsible for innervating the external obturator muscle, pectineus, gracilis, and adductor muscles.

Answer 245

e. Cutaneous lymphoma ## Footnote A 10-year old spayed female Labrador retriever presents for a two-year history of non-seasonal waxing and waning, generalized severe erythema, and scaling (exfoliative erythroderma) with pruritus. The patient had previously been worked up for allergies by performing a diet trial and doing an intradermal skin test, followed by treatment with allergy-specific immunotherapy. The patient did not respond to the diet trial or to allergy specific immunotherapy. On physical examination you note ulceration and thickening of the oral mucosa and hyperkeratotic foot pads in addition to the exfoliative erythroderma. No infectious cause was identified on skin scrapes or skin cytology. You perform a skin biopsy of the exfoliative erythroderma and the oral mucosa because you are suspicious about cancer. Which cancer are you most concerned about?

Answer 246

c. Blood urea nitrogen ## Footnote The correct answer is blood urea nitrogen (BUN). BUN is usually low in patients with hyperadrenocorticism secondary to the increased diuresis that occurs with elevated cortisol levels. ALT increases due to swelling and death of some hepatocytes. SAP increases due to a steroid induced isoenzyme of SAP from the liver. Mild cholestasis due to swelling of hepatocytes also contributes to a minor part of the increase in SAP. Cholesterol is elevated in up to 90% of hyperadrenocorticism cases.

Answer 247

d. Low TLI (trypsin like immunoreactivity) ## Footnote The correct answer is low TLI. TLI is a pancreas specific marker of trypsinogen. Because acinar cells are lost in EPI, levels decrease. Protein levels and cholesterol are usually unchanged in animals with EPI.

Answer 248

c. Panhypoproteinemia The correct answer is panhypoproteinemia. Lymphangiectasia is a classic example of a protein-losing enteropathy. It is characterized by dilation and dysfunction of intestinal lymphatics and leakage of protein-rich lymph into the intestinal lumen. As a result, protein, cholesterol, and lymphocytes are all lost. Calcium is also frequently low due to either low albumin or vitamin D and calcium malabsorption.

Answer 249

c. Aging The correct answer is aging. Aging is the only cause of nuclear sclerosis. It is a normal change to the lens resulting in partial loss of transparency in the middle of the lens.

Answer 250

e. Coagulopathy The toxic principle of chocolate is methylxanthines (specifically theobromine and caffeine). Methylxanthines can cause CNS excitation tachycardia, and vasoconstriction. Signs include vomiting, diarrhea, hyperactivity, polyuria, polydipsia, lethargy, tachycardia, cardiac arrhythmias, seizures, and death.

Answer 251

b. Give dexamethasone. ACTH stimulation test ## Footnote Poodles are the poster children for Addison's disease. Addison's is a tricky disease to diagnose if you are not looking for it. It is also called "the great imitator" as it can look like renal failure, GI disease, or acute collapse. The key signs in this case are the poodle in shock after a stressful event (owners were out of town), low heartbeat with cardiovascular collapse, a lack of stress leukogram in what should clearly be a stressed animal (normal white blood cell count in collapsed shocky patient), and Na:K ratio of less then 30 (hallmark for Addison's), and a USG of less than 1.030. Addison's disease is due to lack of endogenous steroid and mineralocorticoid production. Endogenous cortisol is needed by every body system for proper function, and higher glucocorticoids as seen in stressed patients typically leads to a stress leukogram. Mineralocorticoid deficiency leads to the inability of the kidneys to retain sodium and secrete potassium. Remember, "water follows salt", which leads to hypotonic dehydration due to excessive sodium losses. Any emergency with acute cardiovascular collapse should immediately be treated with IV boluses of fluids and should not wait while you perform your diagnostics. Once your tentative diagnosis has been found, supplementing with IV dexamethasone will help restore steroids to the patient while you await for an ACTH stimulation test to confirm your diagnosis. Dexamethasone is considered the glucocorticoid of choice with suspected Addison's, as it will not interfere with confirmatory testing. This poodle responded within an hour to IV dexamethasone; he was up and alert and responsive. Cortisol levels pre- and post- ACTH gel administration were both low. Addison's is a life long disease that is managed with glucocorticoids (typically prednisone after diagnosis) and mineralocorticoids.

Answer 252

b. Canine thrombopathia The correct answer is canine thrombopathia. The disease is an autosomal recessive trait where platelets fail to aggregate and secrete their granules in response to normal stimuli. Platelet numbers and coagulation parameters are normal.

Answer 253

d. Bone marrow biopsy, serum electrophoresis This dog has signs and bloodwork findings that are consistent with but not specific for multiple myeloma. The hypercalcemia and hyperglobulinemia are both mild and are consistent with this diagnosis but would not be sufficient alone to jump to that conclusion. The key finding in these case is the radiographic evidence of multiple punctate lucencies including in the body of C4, several of the thoracic dorsal spinous processes, the left ilium, and the right and left humeral diaphyses. These lesions are strongly suggestive of multiple myeloma; however, definitive diagnosis of multiple myeloma requires satisfying at least two of the following criteria: 1. Monoclonal gammopathy 2. Radiographic evidence of osteolytic bone lesions (satisfied in this case) 3. \>5% neoplastic cells or \>10-20% plasma cells in the bone marrow 4. Immunoglobulin light chain proteinuria (Bence-Jones proteinuria) Therefore, the best answer in this question is to perform serum electrophoresis to assess monoclonal gammopathy and a bone marrow biopsy to look for neoplastic infiltration of plasma cells.

Answer 254

e. Coxofemoral joint ## Footnote The correct answer is coxofemoral joint. OCD rarely occurs in the coxofemoral joint. The caudal aspect of the humeral head is usually involved in the shoulder. In the elbow, you will usually see them on the medial aspect of the humeral condyles. At the tarsocrural joint, they will be present at the trochlear ridge of the talus. At the stifle, they are located on the femoral condyle.

Answer 255

b. Umbilical arteries The correct answer is umbilical arteries. The urachus becomes the middle ligament of the bladder and the umbilical vein becomes the falciform ligament.

Answer 256

d. High Ca, High P Excessive intake of vitamin D is associated with an increase in 25-hydroxyvitamin D3 levels. At high levels, 25-hydroxyvitamin D3 competes with 1,25-dihydroxyvitamin D3 for its receptors on the intestines and bone causing increased absorption of Ca and P from the intestinal tract and resorption of bone causing increased levels of circulating Ca and P. A common source of confusion is that this is in contrast to PTH which causes high Ca but generally causes unchanged or normal phosphorus because it also enhances renal phosphorus excretion.

Answer 257

d. Corticosteroids The correct answer is corticosteroids. The diagnosis in this case is immune-mediated hemolytic anemia due to the finding on spherocytes on blood smear. If no other precipitating cause is found (infectious disease, neoplasia, etc), treatment is with corticosteroids and other immunosuppressive/immunomodulatory drugs such as azathioprine.

Answer 258

b. Permethrin Permethrin toxicity is a very common cause of poisoning in cats. Cases may result from inappropriate application of spot-on formulations intended for use in dogs, from cats who are in close contact with dogs after application, or from cats who come into contact with the applicator after use. Once dry, permethrin is not toxic to cats; hence the importance of warning the owner to separate the dog and cat for two hours after application. Permethrin is excreted following oxidation and glucuronidation. Cats have a reduced capacity for glucuronidation, which may be attributed to the accumulation of metabolites and a less efficient detoxification process. Permethrin passes through the blood brain barrier and can cause CNS signs, including seizures. Dermal decontamination should be instituted immediately with dishwashing detergent. Dinotefuran, Fipronil, Spinosad, and Imidacloprid are flea adulticides and are the active ingredients in Vectra, Frontline, Comfortis, and Advantage respectively. All of these ingredients are safe for cats and are commonly used adulticides in cat as well as dog products.

Answer 259

b. Dachshund ## Footnote The correct answer is Dachshund. Cushing's syndrome is commonly seen in Dachshunds, particularly long-haired Dachshunds. Other commonly affected breeds include Poodles, Beagles, Boston Terriers, and Boxers. Cushing's syndrome is rare in cats.

Answer 260

a. Perineal hernia The correct answer is perineal hernia. Adult intact male dogs (and cats) are at increased risk of perineal hernias. The deviation of the rectum on rectal palpation is how the diagnosis is usually made. The cause is often not identified, but it frequently occurs as a sequela to chronic tenesmus.

Answer 261

a. Immune mediated adenitis The correct answer is immune mediated adenitis. These can all cause KCS but immune mediated adenitis accounts for about 75% of KCS in dogs.

Answer 262

d. Systemic Lupus Erythematosis The correct answer is systemic lupus erythematosis. SLE causes many signs, but anterior uveitis is not considered one of them. The causes of uveitis include infection (bacterial, viral, fungal, rickettsial), immune mediated (lens-induced uveitis), neoplasia, hypertension, and trauma. Over 50% of the time, the cause is not found and the uveitis is termed idiopathic.

Answer 263

a. Lacrimal gland and gland of the 3rd eyelid The correct answer is lacrimal gland and gland of the 3rd eyelid. KCS comes from a decrease of the aqueous portion of the tear film. This is produced by the lacrimal gland and the gland of the 3rd eyelid. Remember, there are three layers of the tear film. The mucous portion lies against the cornea and keeps the tear film adhered to it. This is made by conjunctival goblet cells. The aqueous portion has nutritional and immunologic factors and is in the middle. It is produced by the lacrimal gland and the gland of the 3rd eyelid. The lipid portion of the tear film is the most outer part, and it allows for even spreading and prevents evaporation of tears. It is produced by the meibomian glands.

Answer 264

c. Liver ## Footnote Phenobarbital is primarily metabolized by the liver. It is contraindicated in cases of severe liver or kidney disease. It can cause an elevation of liver enzymes. There is no direct effect on the kidney by barbiturates, but with high doses, renal impairment can occur due to hypotension from the drug. Liver and kidney values should be frequently monitored in patients on phenobarbital.

Answer 265

a. Diphenhydramine ## Footnote The correct answer is diphenhydramine. This dog has a swollen muzzle most likely due to type 1 hypersensitivity. Diphenhydramine is an anti-histamine and will reduce the clinical signs associated the allergic reaction.

Answer 266

b. Lung mass ## Footnote The correct answer is lung mass. At this point we don't know if this is a metastatic lesion or a primary lung mass. Further diagnostics would be indicated determine the origin of the mass. The mass is located in the region of the caudal vena cava.

Answer 267

d. Provide a lidocaine bolus followed by a continous infusion of lidocaine ## Footnote This patient is exhibiting premature ventricular contractions which is commonly observed after splenectomy. Any patient that has a splenectomy should be monitored closely for that reason. Most of the time these are not severe enough to require treatment. There are some general guidelines for when to treat VPCs which include excessive pulse deficits, the patient is clinically affected, a heart rate greater than 180 bpm, or greater than 20 second stretch of continuous VPCs. In this case it is important to know that the patient was just given a dose of post-operative pain medication (at an appropriate dose) which rules out an elevated heart rate secondary to pain. The patient is anemic, but he is not anemic to the point of requiring an emergency transfusion. Transfusions are usually not administered unless there is expected ongoing blood loss (which is not the case) or the PCV is less than 20. Lidocaine is an anti-arrhythmic and is the typically the drug of choice for treatment of VPCs. A bolus is administered first to determine if the rhythm is responsive to lidocaine and then a CRI is initiated at 20-80 micrograms per kilogram per minute.

Answer 268

b. Respiration ## Footnote Propofol's most common adverse side effect is temporary apnea. You should always be prepared to intubate and ventilate a patient when administering propofol due to the potential for severe apnea. It is certainly not wrong to monitor blood pressure and heart rate to assess anesthetic depth and vital signs, even for a brief procedure; but by far, the most important thing to watch is respiration.

Answer 269

b. Prednisone This is a case of lymphoma. The cytology depicts the classic finding of a population of lymphoid cells that are predominantly lymphoblasts based on their size and characteristics. If you were unsure about their size due to magnification, there is a neutrophil in the lower left corner for comparison. The lymphoblasts are considerably larger than the neutrophil. Mature lymphocytes would be smaller than a neutrophil. Note that there is a mitotic figure in the middle of the slide. There are many treatments and protocols for lymphoma and some of the main agents known to have efficacy are prednisone, doxorubicin, cyclophosphamide, vincristine, L-asparaginase, and lomustine. There are many other efficacious chemotherapeutics for lymphoma but carboplatin is not considered a first line treatment for lymphoma in dogs. The other drugs listed are antifungal (itraconazole), antibiotic (doxycycline) and anti-parasitic (milbemycin).

Answer 270

a. Azathioprine, prednisone, cyclophosphamide ## Footnote For patients with immune-mediated thrombocytopenia, immunosuppressive doses of corticosteroids should be started. Cyclophosphamide can be given to help induce remission. Azathioprine can help maintain remission and can be given long-term, usually with fewer side effects than with corticosteroids. Doxycycline would be given for patients with Ehrlichiosis. Famotidine would be helpful in preventing stomach ulcers while administering corticosteroids. Vitamin K would be given to patients who ingested Vitamin K antagonists like warfarin or brodifacoum (the drugs found in rat poisons). Aspirin would be contraindicated as aspirin decreases platelet aggregation.

Answer 271

a. Left lung ## Footnote The correct answer is left lung. On a right lateral radiograph, the right side is down. In this situation, the right lung lobes are compressed and the left lung lobes inflated, accentuating a mass in the left lung. On a left lateral radiograph, the left lobes are compressed and a mass in the left lung can be concealed due to compression of the lung surrounding the mass.

Answer 272

b. Medial meniscus ## Footnote The correct answer is medial meniscus. The medial meniscus is commonly damaged in a dog with a ruptured cranial cruciate ligament because the meniscus is closely associated with the medial collateral ligament, which prevents the meniscus from moving around within the joint when the femoral condyle compresses and slides against it. The lateral meniscus is not associated with the collateral ligament and can freely move around when compressed by the femur.

Answer 273

d. Respiratory ## Footnote The correct answer is respiratory. The Perilla mint (Perilla frutescens) plant has a pneumotoxin that is absorbed and metabolized to a toxic intermediate that damages Type I pneumocytes and bronchiolar epithelial cells. Animals become acutely dyspneic and may begin open-mouth breathing and frothing at the mouth. Necropsy shows wet, heavy, emphysematous lungs.

Answer 274

b. Immiticide (Melarsomine) The correct answer is Immiticide (melarsomine). The dog in this radiograph has the classic findings for heartworm disease, including right sided ventricular enlargement with very prominent pulmonary arteries. Heartworm in the dog is caused by Dirofilaria immitis. The treatment of choice for heartworm is Immiticide which is given by intramuscular injection. Furosemide is a treatment for congestive heart failure, which this dog shows no evidence of. Terbutaline is a bronchodilator, which would be of little use in this case. Broad-spectrum antibiotics are useful for the treatment of pneumonia and other infections but are not effective against heartworm. Pericardiocentesis is obviously the treatment for pericardial effusion, but this dog's radiographs do not show the classic globoid heart you might see with pericardial effusion. Adulticidal treatments for heartworm are melarsomine and thiacetarsamide.

Answer 275

e. Diaphragmatic hernia Note the raised trachea, with lung lobes floating in the dorsal chest; lung borders outlined clearly by opacity, but the cardiac silhouette indistinct DDx includes NOTHING GOOD---neoplasia, CHF, hypoalbuminemia (secondary to protein-losing nephropathy/liver disease), heartworm, diaphragmatic hernia, trauma/hemothorax, lung lobe torsion to name a few. Pulmonary edema looks different-Think splotchy, cotton-ball lungs, where the tissue of the lung itself is heavy with fluid.

Answer 276

a. Donor red blood cells, donor plasma In a minor crossmatch, you are looking to see if the factors in the plasma of the donor are going to react to the recipient's red blood cells.

Answer 277

a. Spirocerca lupi A disease of dogs in the Southern US and tropical climates, Spirocerca lupi (esophageal worms) make reactive granulomas of variable size in the esophageal, gastric, or aortic wall. Large granulomas may become neoplastic (osteosarcoma, fibrosarcoma). Some dogs develop spondylitis or enlargement of the extremities characteristic of hypertrophic osteopathy. Typically asymptomatic, but large granulomas can cause esophageal obstruction. Spirocercosis may also lead to aneurysm in the thoracic aorta or an ossifying spondylitis of the posterior thoracic vertebrae. Habronema spp. (Habronema muscae, H. microstoma and Draschia megastoma) in horses can cause tumor-like stomach nodules and sometimes cutaneous lesions. Blastomycosis, most common in dogs, cats, and humans is characterized by pyogranulomatous lesions in various tissues. Placental infection in horses with Coccidioides immitis have been described, leading to abortion and osteomyelitis

Answer 278

d. The puppy likely has canine scarbies, which is zoonotic. Contact with puppy should be limited and gloves should be worn when handling the dog ## Footnote The correct answer is the puppy likely has canine scabies which is zoonotic. Contact with the puppy should be limited and gloves should be worn when handling the dog. It is not uncommon for skin scrapings of a scabies patient to be negative for the mite. The signalment, lesion distribution, and clinical impression are sufficient for diagnosing a scabies infestation. Scabies infections are not associated with a genetic defect and are usually responsive to treatment with agents like ivermectin, amitraz, milbemycin oxime, or selamectin. Although the mites are fairly host-specific, they are still considered zoonotic and precautions should be taken when handling the animal.

Answer 279

d. Inappetance ## Footnote The correct answer is inappetance. Mitotane is an adrenolytic agent used for treating Cushing's disease. Giving too high of a dose to a patient will cause iatrogenic Addison's disease, which can be life-threatening. Clinical signs of overdose that owners need to monitor while their dog is taking mitotane include inappetance, vomiting, and diarrhea.

Answer 280

a. Increase in salivary secretion ## Footnote The correct answer is increase in salivary secretions. CNS depression, decrease in intestinal motility, respiratory depression, and decrease in body temperature all occur with mu agonist opioids. Other side effects include panting, cough suppression, and bradycardia.

Answer 281

b. Pericardiocentesis ## Footnote The correct answer is pericardiocentesis. This radiograph and case are a good example of pericardial effusion with the classic finding of a markedly enlarged heart with a globoid shape. The most common type of effusion by far is hemorrhage which can be idiopathic or from neoplasia such as hemangiosarcoma. Based on this finding, in conjunction with the dog's tachycardia, a pericardial tap for both diagnostic and therapeutic purposes is indicated. Furosemide is contraindicated in cases of pericardial effusion because it will decrease preload in the right side of the heart and can promote circulatory failure. Melarsomine is the treatment for heartworm. Antibiotics are very unlikely to help this dog unless the effusion is from some sort of infectious pericarditis, which would be extremely unusual in dogs.

Answer 282

d. Thiopnetal ## Footnote The correct answer is thiopental. Thiopental is an ultra-short acting barbiturate. Recovery depends on redistribution to tissues, including fat. Because sighthounds have very little fat, they have prolonged recoveries and greater complications with these drugs.

Answer 283

b. Antihistamines, corticosteroids, and epinephrine The dog has angioedema +/- anaphylaxis, likely caused by an insect bite or sting. A snake bite should also be ruled out by trying to visualize the bite or questioning the owners. This is a type I hypersensitivity reaction and is treated by removing the offending agent if possible and providing supportive care with anthistamines, corticosteroids, and epinephrine as needed.

Answer 284

a. von Willebrand's disease ## Footnote The correct answer is von Willebrand's disease. This is a hereditary disorder most commonly seen in the Doberman. Platelets lose their ability to adhere to subendothelial collagen and thus function is impaired. This leads to prolonged bleeding times. The platelet count is usually normal with this condition. Rodenticide toxicity could also cause bleeding such as described, but do to the breed in this question, von Willebrand's disease is the best choice.

Answer 285

a. Demodex spp. ## Footnote The correct answer is Demodex. Demodex mites are a natural inhabitant of skin. Clinical signs of a Demodex infection usually occur in puppies or immune-suppressed animals. The other mites listed are considered contagious.

Answer 286

b. Prostatitis ## Footnote The correct answer is prostatitis. Castration does not significantly reduce the risk of prostatic neoplasia or bladder neoplasia. Castration reduces the risk of benign prostatic hyperplasia and prostatitis.

Answer 287

d. Prognosis is usually good but angular limb deformity is a possible complication. Recovery relies on supportive care and can take days to weeks. Most dogs with this disease will have 1 or 2 episodes and recover ## Footnote Hypertrophic osteodystrophy (HOD) is a disease of large, rapidly growing dogs. The distal metaphyses of the forelimbs are more commonly affected and can be swollen. Radiographic findings include metaphyseal flaring and the classic "double physeal line." Treatment is supportive with anti-inflammatories or steroids, pain medications, and activity restriction. Septic arthritis can cause lameness, joint pain and swelling. Radiographs can show bone destruction and osteolysis with chronic disease as well as irregularities in the joint space. Osteosarcoma causes bony lysis and proliferation at the metaphyseal region of long bones. These are commonly in the distal radius/ulna, proximal humerus, proximal tibia, and distal femur ("away from the elbow and towards the knee"). Age does not rule out this disease as it has been diagnosed in animals as young as 6 months.

Answer 288

e. Erythema migrans ## Footnote The correct answer is erythema migrans. Apparently, this is only seen in humans. The other choices are observed with Lyme disease.

Answer 289

e. Prednisone and azathioprine ## Footnote This case is most consistent with immune-mediated polyarthritis (IMPA). IMPA is often classified as being erosive or nonerosive. This case is an example of the nonerosive form based on the lack of radiographic evidence of cartilage or subchondral bone destruction. The erosive form is rare and is thought to account for \<1% of the cases of IMPA. Nonerosive IMPA can be associated with a variety of systemic diseases or precipitating factors including systemic infectious, inflammatory or neoplastic disease or reactions to drugs or vaccines but it is most commonly idiopathic with no association to another disease process. In the described case, no risk factors or signs of concurrent disease were mentioned. Tick-borne arthropathy is less likely with the negative tick titers obtained, but since not every type of tick can be tested for, some clinicians may opt to treat with an antibiotic like doxycycline concurrently with the immunosuppressive drugs. The clinical signs associated with IMPA are anorexia, weight loss, fever, lethargy, and lymphadenopathy. Up to 25% of dogs present with only nonspecific signs of systemic illness and without apparent gait abnormality or joint effusion. It is an important consideration for dogs with fever of unknown origin and may be the cause up to 20% of the time. IMPA is diagnosed by synovial fluid analysis although additional baseline diagnostics are indicated to screen for potential systemic or infectious causes. Normal synovial fluid is clear and viscous with \<2.5 g/dl protein and \<3,000 cells/ul with predominantly mononuclear cells. Joint fluid in IMPA may be thin, turbid, and increased in volume with higher amounts of protein and cells, often primarily nondegenerate neutrophils. Treatment of idiopathic IMPA centers on immunosuppressive therapy, often starting with prednisone and sometimes including an additional immunosuppressive drug such as azathioprine or cyclophosphamide. About 80% of dogs will respond to immunosuppressive doses of prednisone; however, about one half of dogs require long-term or additional drug therapy to maintain remission.

Answer 290

c. Breed related ## Footnote Canine pinnal alopecia is a form of pattern alopecia. Pinnal alopecia is most commonly diagnosed in Dachshunds, but can be seen in Chihuahuas, Boston Terriers, Bull Terriers, Yorkshire Terriers, and Italian Greyhounds. The condition usually occurs in dogs older than 1 year of age and results in slowly, progressive, bilateral pinnal alopecia. The ear margins may become chronically hyperpigmented and thickened. The condition is benign and requires no specific treatment. Distribution of the alopecia is an important key to determining the underlying diagnosis. It may help in distinguishing inflammatory from non-inflammatory causes, thus narrowing down your differential list. Inflammation results in a patchy pattern of alopecia that is not symmetrically distributed; whereas, many of the noninflammatory alopecias have a symmetrical pattern of alopecia. Hypothyroidism often causes alopecia of the tail and may also be associated with alopecia of the nose bridge. Hair loss begins with the pinna at 6 to 9 months of age and may progress to complete pinnal alopecia. Total body alopecia with pigmentation may occur with age. Treatment with oral melatonin may cause hair regrowth with this and other pattern baldness syndromes. Other medications that can be used with variable success are pentoxifylline and Omega 3 oils topically.

Answer 291

d. Maintaining urine specific gravity of \< 1.020 ## Footnote The correct answer is maintaining urine specific gravity \<1.020. An important principle in management of any patient with urolithiasis is to maintain dilute urine so that solutes do not concentrate to the degree that they form precipitates that lead to stone formation. Struvite stones (magnesium ammonium phosphate) tend to form in alkaline urine so ideal urine pH for struvite stone formers is usually around 6.5. Other principles of management are to decrease urea in the urine, often done by moderate protein restriction and to decrease the minerals involved (magnesium and phosphate). Finally, a key element in struvite stone formation is the presence of a urinary tract infection, particularly with urease-producing microbes, most notably staphylococcus and proteus. Monitoring, preventing, and treating UTIs is an important aspect of management of these patients.

Answer 292

d. GIardia The correct answer is Giardia. Young, immunodeficient, and grouped animals tend to show signs. This question provides a classic description of the motile trophozoite. Remember, the cyst is the infective mode, not the trophozoite. T. foetus has an undulating membrane which helps you differentiate from Giardia along with 3-5 anterior flagella. Additionally, T. foetus is not commonly found in dogs. When looking for Isospora, you would expect to see them on a fecal flotation in the form of oocysts. Cryptosporidium would be round and slightly smaller than a red blood cell. Acid-fast or fluorescent antibody stains are performed on direct fecal smears to help find these small organisms.

Answer 293

b. Surgical replacement of the abnormality This image shows a dog with bilateral "cherry eye" or prolapse of the gland of third eyelid. The recommended therapy is gland replacement by the Morgan pocket technique or Kaswan anchoring technique. Removal of the gland places dogs at increased risk of developing keratoconjunctivitis sicca (KCS).

Answer 294

c. Hemolysis ## Footnote The correct answer is hemolysis. Zinc causes a Heinz body anemia and hemolysis

Answer 295

d. Heinz body anemia ## Footnote The correct answer is Heinz body anemia. The toxic compound in mothballs is naphthalene which can cause acute hemolytic anemia, Heinz body anemia or methemoglobinemia, vomiting, and seizures.

Answer 296

d. Triglyceride concentration of the fluid compared to serum Explanation The correct answer is triglyceride concentration of the fluid compared to serum. The fluid described is most consistent with a chylous effusion. The best way to definitively classify chyle is finding an elevated triglyceride level compared to serum. If you chose differential cell count, this is also a good answer because most chylous effusions are composed primarily of lymphocytes, unlike other effusions. However, with prolonged loss of lymphocytes, chronic chylous effusions may be composed primarily of neutrophils, which may lead you to believe it is an exudate. Radiographs and culture and sensitivity may be appropriate tests but will not help you classify the fluid. Glucose concentration of the fluid is not useful in this instance. It is sometimes used to diagnose pyothorax as glucose concentrations are typically \< 10 mg/dl.

Answer 297

b. Actinomyces ## Footnote The correct answer is Actinomyces. This is a filamentous, branching, gram positive bacteria that is a normal inhabitant of the mouth and oropharynx. It is commonly associated with grass awn migration. These are usually contaminated in the oropharynx and then migrate through the body from the respiratory or GI tracts. Many times it takes months to years to make a diagnosis. Nocardia is a ubiquitous soil saprophyte found everywhere and is usually introduced via the respiratory tract.

Answer 298

d. Peripheral nerve sheath tumor ## Footnote The correct answer is peripheral nerve sheath tumor. The presentation of the dog described is classic for a peripheral nerve sheath tumor. They are slow growing tumors arising from the peripheral nerve sheath cells. They are most commonly found in the brachial plexus. Limb amputation and tumor excision may be curative if the spinal canal has not been invaded.

Answer 299

c. Piroxicam ## Footnote This is an example of a mast cell tumor. All of the choices are acceptable treatments except for Piroxicam. Because mast cells contain and secrete histamine, administration of an H2 antagonist such as famotidine and an H1 antagonist such as diphenhydramine can reduce systemic signs associated with histamine release. Prednisone and Vinblastine are both appropriate chemotherapeutics for mast cell tumors in dogs. Piroxicam is a cyclooxygenase inhibitor (NSAID) and is not an effective chemotherapeutic for mast cell tumors. Additionally, its potential to cause adverse side effects to the stomach and small intestine can increase the risk of gastroenteritis or perforation in a dog with hyperhistaminemia.

Answer 300

a. Visceral larva migrans ## Footnote The correct answer is visceral larval migrans. Cutaneous larva migrans is caused by Ancylostoma spp., the canine hookworm. Hydatid cyst disease is caused by Echinococcus granulosus.

Answer 301

c. Medial ## Footnote The correct answer is medial. Luxating patellas in both small and large breed dogs occur more commonly to the medial side. Some large breed dogs will luxate laterally but not as frequently as to the medial side. Small breed dogs rarely have luxating patellas to the lateral side.

Answer 302

e. Iron deficiency ## Footnote The correct answer is iron deficiency. The CBC shows a microcytic, hypochromic, non-regenerative anemia. Reticulocyte counts under 60,000/ul are typically considered non-regenerative in most labs. This is consistent with chronic iron deficiency. This most common reason for chronic blood loss is gastrointestinal tract disease such as an ulcer or cancerous lesion.

Answer 303

d. Dog ## Footnote The correct answer is dog. Only the dog synthesizes a corticosteroid induced isoenzyme of ALP.

Answer 304

b. Euthanize and test ## Footnote The correct answer is euthanize and test. Because the animal is a stray it should be euthanized and tested, regardless of the presence of clinical signs of rabies.

Answer 305

a. Thrombocytopenia The correct answer is thrombocytopenia. Polyphagia, panting, increased susceptibility to infections, and hyperpigmentation of skin are side effects seen with administration of high doses of glucocorticoids. Thrombocytosis may be seen as well, but thrombocytopenia is not expected.

Answer 306

d. PaCO2 \< 30 mmHg ## Footnote The correct answer is PaCO2 \< 30 mm Hg. Ventilation is defined by the PaCO2. Normal is 35-45 mmHg. A hypoventilated patient has a high PaCO2, and a hyperventilated patient has a low PaCO2.

Answer 307

b. Start a tyrosine kinase inhibitor chemotherapy drug ## Footnote Under the Patnaik grading system, grade 3 tumors are highly metastatic. Mast cell tumors are highly responsive to radiation therapy, but with clean excision and wide surgical margins, local recurrence is unlikely. Metastasis is the primary concern and a wait and monitor approach is not advised. Even with no evidence of metastasis at the time of surgery, chemotherapy should be initiated as soon as possible. Common protocols include single agent or alternating vinblastine and lomustine. Tyrosine kinase inhibitors, such as toceranib (Palladia) and masitinib (Kinavet, which is no longer available), target c-kit, a stem cell factor receptor involved in mast cell proliferation and differentiation. Palladia and Kinavet are FDA approved for treatment of high-grade canine cutaneous mast cell tumors.

Answer 308

c. Transitional cell carcinoma ## Footnote The most common urinary bladder tumor is transitional cell carcinoma. You can often see abnormal cells on the urinalysis, but use the caution in diagnosing on urinalysis alone, as inflammation can cause a similar appearance with a much more positive prognosis. Biopsy is needed for definitive diagnosis. Chemotherapy can help these patients shrink the tumor for a time (for a better quality of life); however, the overall prognosis is grave.

Answer 309

d. Right atrium ## Footnote The correct answer is right atrium. Although the reason for this predilection is unknown, this is the most common site in the heart for hemangiosarcoma to occur.

Answer 310

c. Toxocara canis ## Footnote The correct answer is Toxocara canis. The most common method of transmission of Toxocara canis is transplacentally. Larvae in the somatic tissue of a pregnant bitch are mobilized during pregnancy and infect the fetuses transplacentally.

Answer 311

a. Flank and prepubic region ## Footnote Traumatic injuries are more likely to cause a flank or prepubic hernia than any other type of reported hernia. Umbilical hernias are almost exclusively congenital in nature. Perineal hernias are seen in older male dogs and is thought to be secondary to excessive hormones that result in weakening of the pelvic diaphragm. Finally, diaphragmatic hernias can occur secondary to trauma but are not as commonly noted as flank and prepubic. Whenever a patient presents with unknown trauma or after being hit by a car, it is appropriate to take x-rays as 20% of dogs with diaphragmatic hernias will present several weeks after injury as a result of missing the diagnosis on physical examination alone.

Answer 312

a. Coagulation panel ## Footnote The correct answer is coagulation panel. If you have compromised liver function, the liver may not be able to produce enough coagulation factors; thus a surgical procedure would bring the risk that the animal could bleed to death.

Answer 313

b. Omega-3 fatty acid, decreases inflammation Omega-6 fatty acid can indeed improve coat quality, but atopic patients benefit more from the action of omega-3 fatty acid to decrease inflammation.

Answer 314

d. Food allergy ## Footnote Food allergy is most likely, since it fits the clinical signs and history. Food allergy typically begins anywhere from 6-9 months of age and in older dogs. Pruritus is non-seasonal, and secondary skin and ear infections can develop. Environmental allergy typically presents after 1 year of age. It is usually seasonal but can be non-seasonal. Contact allergy doesn't fit the distribution of clinical signs; generally with contact allergy you observe pododermatitis and dermatitis of the ventral abdomen from the dog laying in plants or other irritants. Additionally, dogs with contact allergy typically do not have otitis externa (unless the contact allergen is in the ear wash). The distribution of clinical signs does not fit flea allergy (caudal/dorsal distribution), and the patient is already on flea control.

Answer 315

a. Vomiting ## Footnote The correct answer is vomiting. Vomiting does not commonly occur with hyperadrenocorticism. Panting and lethargy are thought to occur as a sign of muscle weakness and exercise intolerance. Increased occurrence of infections is due to immune suppression. Distended abdomens develop from redistribution of fat into the abdomen.

Answer 316

c. Free T4 The correct answer is free T4. Free T4 is the most accurate test for diagnosing canine hypothyroidism (about 95% accuracy), but it is expensive to run. It is usually only run if the results of a total T4 (about 85% accurate) are unclear. A thyroglobulin autoantibody test is run to determine if the etiology of the hypothyroidism is due to lymphocytic thyroiditis. Endogenous cTSH is 80% accurate in diagnosing canine hypothyroidism.

Answer 317

a. The patient's serum calcium should be monitored daily for about a week to check for the development of hypocalcemia The correct answer is the patient's serum calcium should be monitored daily for about a week to check for the development of hypocalcemia. Post-operatively, it is important to monitor for hypocalcemia daily for the first seven days regardless of the absence of clinical signs for hypocalcemia. The higher the pre-operative serum calcium concentration, the more likely the patient will become hypocalcemic post-operatively. Post-operative monitoring of serum calcium should be daily for the first seven days, then weekly for 4 weeks. Vitamin D and calcium supplementation should be given accordingly. Serum calcium concentration should be maintained in the low normal range, not below normal, to stimulate production of PTH by the parathyroid cells.

Answer 318

b. Lethargy, anorexia ## Footnote The answer is lethargy and anorexia. Dogs with EPI are actually polyphagic rather than anorectic. Common clinical signs of EPI are weight loss with polyphagia, vomiting, passage of voluminous pale diarrhea, abdominal discomfort, and coprophagia (eating feces).

Answer 319

b. It will probably also develop glaucoma in 6-12 months ## Footnote The correct answer is that it will probably also develop glaucoma in 6-12 months. The usual course for primary glaucoma is development in one eye with the contralateral eye following in 6-12 months. These animals have an iridocorneal angle that becomes increasingly compromised during the first few years of life and eventually causes an acute pressure spike in the eye.

Answer 320

c. Lens ## Footnote The correct answer is lens. This dog has bilateral incomplete cataracts. Cataracts have a variety of causes including aging, intraocular disease, endocrine disease (especially diabetes mellitus) and radiation exposure. A cataract is characterized by increasing opacity to the lens of the eye. It can be difficult to judge depth on a photograph but the answer should be apparent due to the classic appearance and the fact that you can only see the affected area through the pupil.

Answer 321

a. 25 ## Footnote The correct answer is 25 mls. You would add 25 mls of the 2% chlorhexidine solution to the 1000mls of saline to get a 0.05% lavage solution. To be absolutely perfect, you would want to remove 25 mls of the saline before adding the chlorhexidine solution.

Answer 322

b. Diestrus ## Footnote The correct answer is diestrus. In diestrus, progesterone is the predominant hormone, and it promotes endometrial growth, suppresses myometrial activity, and inhibits leukocyte response to infection. This all predisposes the dog to development of pyometra.

Answer 323

e. Atrial fibrillation ## Footnote The correct answer is atrial fibrillation. Although the rate is not fast, there are no discernible P waves and the R-R interval varies with each beat. This irregularly irregular rhythm is a hallmark of atrial fibrillation. Normal sinus rhythm and sinus arrhythmia are incorrect as there are no P waves apparent. Atrial premature complexes is wrong because the irregularity is from the fibrillation waves in the atria, not a discrete premature focus. Second degree heart block is not correct because no P waves are seen, as would be expected with intermittent block.

Answer 324

d. Cryptorchidism is a heritable characteristic in dogs and his offspring may be affected ## Footnote The correct answer is cryptorchidism is a heritable characteristic in dogs and his offspring may be affected. Dogs with one testicle are not considered infertile. One testicle is enough to inseminate a bitch. Adverse health risks resulting from leaving a cryptorchid testicle in the abdomen includes the development of Sertoli cell tumors.

Answer 325

e. Miniature Schnauzer ## Footnote The correct answer is Miniature Schnauzer. Clinically affected dogs may be predisposed to seizures, pancreatitis, acute blindness, vomiting, and corneal opacities. Management is via low-fat diets.

Answer 326

d. Transmissible venereal tumor The correct answer is transmissible venereal tumor. Complete cure is seen in over 90% of patients treated with vincristine. Cure rates for all of these other tumor types with chemotherapy alone is very low, although remission can certainly be attained in a large percentage of lymphoma cases.

Answer 327

a. Internal fixation ## Footnote The correct answer is internal fixation. Proper internal fixation will achieve the best reduction and thereby maximize the chances of adequate healing. Small breed dogs have a decreased blood supply to distal limbs, which results in a slower healing of fractures and a higher incidence of non-union when there is no surgical intervention.

Answer 328

a. Tenesmus ## Footnote The correct answer is tenesmus. Tenesmus is a sign of large bowel disease rather than small bowel. Vomiting is a consistent sign of small bowel obstruction. Diarrhea is also common and is due to bacterial overgrowth due to the obstruction and sometimes due to vascular obstruction. Abdominal pain is also a common sign.

Answer 329

e. Surgery to assess the abdomen and perform a gastropexy ## Footnote To correctly answer this question, it is important to recognize the signalment. In this case, you have a deep-chested large breed dog. These dogs are predisposed to gastric dilatation and volvulus (GDV). Additionally, the history of acute onset and clinical signs are consistent with GDV. Initial stabilization frequently involves rapid administration of IV crystalloids through the cephalic vein, appropriate diagnostic assessment, and stomach decompression. This can frequently be a surgical emergency to reposition the stomach. Even if the patient can initially be adequately treated non-surgically, a gastropexy should be performed to prevent the high risk of a subsequent episode of GDV. Looking at the other answer choices, isolation and supportive care would be appropriate for acute viral enteritis such as parvovirus. That is not a good differential in this case due to the age of the dog, as parvovirus is primarily a disease of puppies. Surgery to remove a gastric foreign body and a low-fat diet for suspected pancreatitis are reasonable considerations, but the abdominal distension seen on your physical exam should push you towards GDV as a diagnosis. This should be confirmed radiographically and surgical treatment would involve a gastropexy to anchor the stomach in place so a GDV does not recur.

Answer 330

e. Dog ## Footnote The correct answer is dog. Only the dog synthesizes a corticosteroid induced isoenzyme of ALP.

Answer 331

c. Hyposensitization injections based on intradermal skin test results Based on the signalment, history, and physical exam findings, you should be most suspicious of atopic dermatitis (atopy). Atopy can occur in any aged dog but typically begins in dogs between 1.0 and 3 years of age. It frequently can be seasonal, in contrast to food allergy. Ultimately, atopy is frequently a diagnosis of exclusion made by ruling out flea and food allergy with measures such as strict flea control and an elimination diet. However, enough clues are given here, and the question specifically asks for the treatment for the most likely underlying etiology. Fipronil (Frontline) and S-methoprene are flea insecticidal therapies. The distribution of the lesions makes flea allergy less likely, and additional flea insecticides unwarranted. Cephalexin and chlorhexadine shampoos are treatments for pyoderma; pyoderma can occur secondary to any allergic skin disease but is not the likely underlying etiology in this case.

Answer 332

d. Aortic stenosis Aortic stenosis (also called sub-aortic stenosis [SAS]), is a systolic, ejection-type (crescendo-decrescendo) heart murmur which may be heard most loudly on the left chest between the 2nd and 5th intercostal (IC) space or at the thoracic inlet (lateral to trachea). Inherited in Newfoundlands. Predilection in many BIG BREEDS - German Shepherd, Golden Retriever, Boxer, ROttweiler. _Mitral dysplasia_ and other mitral valve problems are heard further back on left at 5th-6th IC. Most common in CATS. With _pulmonic stenosis_ see RIGHT ventricular hypertrophy, because pulmonic valves blocks outflow from R ventricle (mostly dogs). _Tricuspid dysplasia_ is heard further back on RIGHT at 5th-6th IC. Uncommon. Except a continuous murmur with _patent ductus arteriosus_ (PDA). Vast majority detected at first vaccination visit

Answer 333

a. Fawn-colored Doberman Pinschers ## Footnote The correct answer is fawn-colored Doberman Pinschers. Yorkshire Terriers are also commonly affected. Color dilution alopecia is a hereditary alopecia that only affects the areas that are color diluted. Treatment is difficult. There are anecdotal reports that suggest retinoic acid and melatonin can be beneficial.

Answer 334

b. Xanthine The correct answer is xanthine stones. Allopurinol is used in the treatment of urate stone forming Dalmatians. It acts by inhibiting the enzyme, xanthine oxidase, which metabolizes xanthine. The idea is that by stopping the purine metabolism pathway at this point, uric acid will not be formed in high quantities. However, if given at too high of a dose, xanthine will accumulate to levels where xanthine stones will form.

Answer 335

c. Topical administration of imidacloprid and permethrin Based on the signalment, history, and physical findings, you should be most suspicious of flea allergy dermatitis (FAD). FAD can occur in any aged dog but typically dogs over 6 months of age. Unlike canine atopy and food allergies which usually have a gradual onset of pruritic signs, FAD can have a rapid onset, as described in this case. Additionally, the distribution and description of the lesions over the caudal half of the body are classic for canine FAD. The most common sites affected for atopy or food allergy are the face, paws, distal extremities, ears, and ventrum. There are many treatment options for FAD including: Imidacloprid (Advantage), also available with 44% permethrin as "Advantix". Fipronil & S-Methoprene (Frontline Plus) Selamectin (Revolution) Nitenpyram (Capstar) Lufenuron (Program), also available with milbemycin as (Sentinel) Spinosad (Comfortis) Dinotefuran, Permethrin & Pyriproxifen (Vectra 3D) Afoxolaner (Nexgard) In addition to insecticidal treatments, flea allergy sometimes needs to be treated with anti-pruritic or antibiotic drugs to address secondary infection; however, the question is specifically asking for treatment of the primary underlying etiology, which, in this case, is the presence of fleas. Hyposensitization injections would be the treatment for atopic dermatitis. A dietary change would be appropriate for food allergy. Antibiotics would be appropriate for a primary pyoderma. Cyclosporine is an adjunct therapy used in atopic dogs.

Answer 336

a. Malassezia infection ## Footnote Malassezia infection of the claws often produces a red-brown discoloration. Other clues that this is more likely Malassezia include biting at the nails (sign of pruritus), multiple claws are infected, and the dog has other symptoms of allergy (pruritus in summer months), which could be this patient's underlying disease. Trauma and neoplasia are less likely since multiple claws are infected, and these typically are not pruritic unless there is a secondary bacterial component. Symmetrical lupoid onychodystrophy results in severe splitting and deformation of the nails. Sarcoptes does not discolor the nails.

Answer 337

b. Mucin ## Footnote Excess amounts of the dermal ground substance component mucin is responsible for the wrinkled appearance of Shar-Peis.

Answer 338

a. Sodium levothyroxine (Soloxine) ## Footnote The correct answer is sodium levothyroxine (Soloxine). Sodium levothyroxine or Soloxine is a synthetic T4 used as the treatment of choice for hypothyroidism. Methimazole is used for treating hyperthyroidism in cats. Mitotane or Lysodren is used to treat hyperadrenocorticism.

Answer 339

d. Supraventricular tachycardias may progress to atrial fibrillation and cause progressive left ventricular dysfunction, whereas ventricular tachycardias may lead to ventricular fibrillation and death ## Footnote Supraventricular tachycardia can lead to atrial fibrillation, which is not life threatening. With atrial fibrillation, the atrial depolarization rate in a dog is usually from 400-700/minute. Usually, about one third of depolarizations get through the AV node to the ventricles to cause a ventricular contraction. Rapid supraventricular arrhythmias can wear out the LV myocardium causing LV dysfunction. Ventricular tachycardias, however, can cause electrical instability and progress to ventricular fibrillation, which leads to cardiovascular collapse and death if not rapidly converted back to a normal rhythm.

Answer 340

a. 20cm H2O ## Footnote Pressures above 20cm H20 may result in barotrauma. In an otherwise healthy patient it is not recommended to exceed this pressure. In patients with chronic atelectasis, anesthetists will be much more apprehensive about over ventilating or ventilating the lungs too quickly, as acute expansion can trigger re-expansion pulmonary edema, which may then lead to acute respiratory distress syndrome and death.

Answer 341

c. 10mL/kg/hr of lactated ringers The correct answer is 10 ml/kg/hr. Animals under anesthesia for surgery need 5-10 mls/kg/hr of an isotonic crystalloid for "maintenance". Obviously, this is sometimes not done for short procedures in healthy animals. Note that this is substantially higher than the usual maintenance fluid requirement for a dog of 2-3 ml/kg/hr. This increased requirement compensates for evaporation during surgery, metabolism of water, and lack of intake.

Answer 342

b. 6 mEq/hr ## Footnote The maximum safe rate of potassium infusion is 0.5 mEq/kg/hr. As this dog weighs 12 kg, the maximum is 6 mEq/hr. This is one of those rates that you need to know. Administering potassium more rapidly than this can result in fatal arrhythmias.

Answer 343

b. The dog likely has an inherited defect in cellular immunity. The dog should not be bred ## Footnote The correct answer is the dog likely has an inherited defect in cellular immunity. The dog should not be bred. Generalized demodicosis in juveniles and puppies is usually caused by an inherited defect in cell immunity. They should be treated with a mite killing agent like ivermectin, amitraz, or milbemycin, as well as with oral antibiotics for secondary bacterial infections. Spontaneous remission of the infection can occur, but the prognosis is always guarded. Demodex mites are part of the natural flora of a dog's skin, so they are normally present all the time. Adult dogs that develop generalized demodicosis are usually immune-suppressed.

Answer 344

a. This will regress within a year, and symptomatic support is needed for discomfort Craniomandibular osteopathy (CMO) is seen in young dogs and is exemplified in this radiograph. Terrier breeds predominate, but CMO can be seen in any breed. The disease is self-limiting and regresses typically by 1 year old. It is thought to be a type of hypertrophic osteodystrophy (HOD) and occurs mostly in the mandible but can also affect the tympanic bulla, temporal bones, and temporomandibular joints. Treatment is supportive with nonsteroidal anti-inflammatories to control pain, similar to HOD. Radiographic signs will also regress with time.

Answer 345

e. VII, III The answer is VII, III. Closure of the eyes is performed by the orbicularis oculi muscle innervated by the facial nerve. Opening of the eye is by the levator palpebrae superioris innervated by the oculomotor nerve. The trigeminal nerve supplies sensory innervation to the eye.

Answer 346

b. Trimethoprim-sulfa Systemic sulfonamides like trimethoprim-sulfa have been associated with keratoconjunctivitis sicca (KCS) sometimes irreversibly. Another drug-associated cause of TRANSIENT KCS is the combination of recent general anesthesia and atropine. Other causes of KCS include: distemper, immunologic (think ATOPY), breed (Pugs, Yorkies), and trauma (proptosed eyeball)

Answer 347

b. Cheyne-Stokes breathing Cheyne-Stokes is a respiratory pattern seen in patients with head trauma and damage to the respiratory centers. It occurs with direct or ischemic damage to the brain, or when cerebral edema and/or increased intracranial pressure are present. It is a usually a bad sign as herniation of the brain may be imminent. Cheyne-Stokes also occurs in patients who are too deep under anesthesia, and is reported as a side effect of morphine in humans. Other signs of brain damage in this patient are the bradycardia and abnormal pupils

Answer 348

d. The lesion should resolve with topical antibiotic treatment Most acral lick lesions are solitary and affect the carpus or metacarpus. About 50% will be diagnosed as idiopathic or psychogenic, but other diseases must be ruled out first including bacteria, fungal, demodicosis, trauma, allergy, and underlying joint disease. A full work-up may include skin cytology, fungal culture, biopsy, diet trial, skin testing, radiographs of the joint, and addressing behavioral disorders. Most of these lesions will have a deep bacterial infection and treatment should include systemic antibiotics based on a deep culture sample. Topical antibiotics may not penetrate the area well enough to resolve the infection. Management also includes treating the underlying cause. Many veterinarians will also prescribe topical or intralesional steroids. If no cause is found, then antidepressants or anxiolytics may be started. These lesions will rarely go away unless the underlying cause is identified and properly treated.

Answer 349

b. Systemic antibiotics for 3-4 weeks and start a diet trial with a novel protein diet The correct answer is to administer systemic antibiotics for 3-4 weeks and start a diet trial. Superficial bacterial infections require antibiotics for at least three weeks. Deep infections require antibiotics for 6-8 weeks. The decision to stop antimicrobial therapy should ideally be based on clinical signs. The general rule is to stop antibiotics 2 weeks after clinical resolution. In practice, this can be difficult because it would require multiple re-checks. Topical therapy with an antimicrobial shampoo can be beneficial, but this infection appears generalized and severe; therefore systemic antibiotic therapy is warranted. As with any bacterial infection there is usually an underlying cause. The logical next step would be to perform a diet trial and rule out food allergy before work-up of environmental allergies. Environmental allergy is a diagnosis of exclusion and flea, food, and contact allergies must be ruled out before a diagnosis of environmental allergies is made. Additionally, intradermal testing cannot determine if a patient has environmental allergies or not, since normal dogs will also test positive. Additionally, this dog most likely has a food allergy based on the age of onset of clinical signs. Food allergy occurs usually before a year of age whereas environmental allergies occur after 9 months to 1 year of age.

Answer 350

d. Sarcoptic Mange The lesions in the image are pustules, which form with neutrophilic inflammation and are accumulations of dead or dying polymorphonuclear leukocytes. Pustules are seen with differing types of dermatitis ranging from bacterial pyoderma, demodicosis, allergic reaction, and pemphigus. Determining the primary etiology will aid in proper treatment and resolution. Diagnostics that are always appropriate for diagnosing skin infections include skin scraping, impression smears, hair plucking for fungal culture, and biopsies if the preliminary diagnostics are unrewarding. Woods lamp can be used as well to diagnose dermatophytosis; however a negative results does not preclude a dermatophyte infection and culture should be pursued. Demodicosis is the only mite infection that has been known to cause pustules or papules. Sarcoptes, Cheyletiella, and Otocaria are not known to cause pustules. Sarcoptes is also usually associated with intense, not mild, pruritis. Dermatophytosis and Trombiculosis can cause pustules, but this is not routinely seen.

Answer 351

b. Hypernatremia The correct answer is hypernatremia. The classic laboratory finding for an Addisonian includes hyponatremia, hyperkalemia, azotemia, anemia, acidosis, hypoglycemia, and of course a low resting cortisol level or low ACTH stimulation test result.

Answer 352

Focal fibrous hyperplasia The correct answer is focal fibrous hyperplasia. Most epulides of dogs are benign fibrous hyperplasia. Malignant melanoma is the most common malignant oral tumor of dogs.

Answer 353

e. Anterior uveitis The correct answer is anterior uveitis. Hyphema and keratic precipitates are specific signs of anterior uveitis. At this point, the cause is undetermined in this animal. While some of these other answer choices may be present in conjunction with uveitis, they are not described by the signs listed in the question.

Answer 354

b. Administer milk to dilue the stomach contents The correct answer is to dilute the stomach contents with milk. Bleach, even when diluted can be corrosive as can many household cleaners. This can result in severe burning of the mouth, esophagus, and stomach. Lesions from acids usually appear soon after exposure, while lesions from alkalis may not appear until 8-12 hours later. Do not induce vomiting with apomorphine because further damage can occur to the esophagus. Activated charcoal does not bind to these products and shouldn't be used. IV fluids is unlikely to be of any benefit immediately following the ingestion of the bleach unless the animal happens to already be sick or dehydrated. NSAIDs may help with pain or discomfort but can also contribute to the formation of ulcers within the GI tract. The recommended course of action is to dilute with milk or water and start GI protectants for several days. If the patient becomes depressed or anorectic, evaluate it for ulcers.

Answer 355

d. 0.1mg/kg preservative free morphine given epidurally Epidural morphine is an effective analgesic for 12-24 hours, while lidocaine lasts only several hours. Fentanyl is a short acting opioid and would only be effective over 12 hours if given repeatedly or as a constant rate infusion (CRI). The effects of hydromorphone last only 4-6 hours.

Answer 356

d. Surgical debulking followed by radiation therapy The image shows a classic example of a mast cell tumor. Note the large number of mast cells (bluish-purple round cells) and all the granules that are present throughout the inside and outside of the cells. Treatment of mast cell tumors in this region usually involves debulking gross disease with surgery and then radiation therapy, as it is difficult to achieve clean margins at this location. The adjuvant radiation therapy results in very good long term control for most mast cell tumors. Prednisone and diphenydramine may be used as anti-inflammatories, but they do not result in control or cure of the disease. Diphenhydramine and Famotidine are excellent therapies to use in the mean time before surgery. Cyclosporine causes T-cell modulation and is typically used for immune-mediated conditions. Mast cell tumors are not immune-mediated. There is no bacteria noted on the slide that would imply antibiotic therapy is needed.

Answer 357

d. Rickettsia rickettsii

Answer 358

a. Vomiting ## Footnote Vomiting is never seen as a result of Cushing's disease, but can be seen with Addison's disease. PU/PD and alopecia are very commonly seen in dogs with Cushing's disease due to the increased blood cortisol levels.

Answer 359

c. Ileum ## Footnote The correct answer is ileum. Disease affecting the ileum will commonly lead to Cobalamin deficiency.

Answer 360

e. Administer fluids and prepare the patient for exploratory laparotomy Based on the presence of neutrophils and bacteria (intracellular) in the abdominal fluid, you should have diagnosed this Newfoundland with septic peritonitis. Although the underlying cause has not yet been determined, peritonitis should be treated on an emergency basis as a "wait and see" approach will likely result in further debilitation of the patient and worsening of the prognosis. The treatment for septic peritonitis is exploratory surgery and correction of the underlying problem (common problems include perforating ulcer/ruptured bowl, ruptured gall bladder, neoplasia, or foreign body/penetrating would). If no underlying problem is found, the peritoneal cavity should be rinsed repeatedly with sterile saline and the abdomen should be allowed to drain. After surgery, appropriate management with fluids, antibiotics (based on culture and sensitivity), gastrointestinal protectants and analgesics should be continued or implemented. The other answer choices here are not the preferred action because you should not postpone surgery longer than is necessary to stabilize the patient for anesthesia and surgery. Septic peritonitis is unlikely to resolve with antibiotic therapy alone and there is concern about selecting for antibiotic-resistant bacteria in such an instance. For routine surgery, it could be appropriate to prioritize an echocardiogram due to the history of mild subaortic stenosis but not in this instance.

Answer 361

b. Small intestinal bacterial overgrowth ## Footnote The correct answer is small intestinal bacterial overgrowth (SIBO). This occurs because of the loss of antibacterial factors from pancreatic fluid as well as altered intestinal motility and decreased immunity from malnutrition. Concurrent SIBO can often exacerbate clinical signs and complicate therapy for EPI. The other choices listed are not sequela to EPI.

Answer 362

b. Sudden Acquired Retinal Degeneration Syndrome (SARDS) The correct answer is SARDS. SARDS is a condition seen usually in middle-aged obese female spayed dogs. They develop acute blindness and initially have no optic or fundoscopic lesions. In 1-2 months, they will develop retinal vascular attenuation and tapetal hyperreflectivity. A primary brain tumor would be more likely to show progressive signs. Retinal detachment and progressive retinal atrophy would show changes in the retina on fundic exam.

Answer 363

b. Uniform lung consolidation The correct answer is uniform lung consolidation. An air bronchogram is an area of uniform lung consolidation around an air filled bronchus. This is usually referred to as an alveolar pattern. This can occur with inflammatory diseases, severe edema, lung lobe torsions, hemorrhage, or some neoplasms.

Answer 364

d. The dog probably has aspiration pneumonia ## Footnote The correct answer is that the dog probably has aspiration pneumonia. Aspiration pneumonia is the most likely complication from this type of anesthesia and surgery. Coupled with the radiographic findings, it is the best choice. A pneumothorax from surgery or pneumomediastinum from tracheal tube trauma could both certainly occur but don't quite fit this scenario. If you were wondering how soon you would see respiratory signs from aspiration and radiographic signs, it can be very quickly.

Answer 365

a. Oral vitamin K1 IF PT or PIVKA tests elevated at 48 or 72 hours in a case-patient with suspected anticoagulant rodenicide toxicity, start oral vitamin K1 at 1.5-2.5mg/kg q12h or 3-5mg/kg once daily. COntinue treatment for 14-30 days, depending on the specific anticoagulant Warfarin is a first generation, shorter-acting anticoagulant, brodifacuom is a second-generation long-acting anticoagulant PT or PIVKA should be checked 48 hours after the last dose of vitamin K1 IF PT or PIVKA is still elevated 48 hours after last dose (16 to 32 days postexposure), restart vitamin K1 treatment for 1 week, then recheck PT or PIVKA 48 hours after last dose. Once the PT or PIVKA is normal at 48 hours, you can stop vitamin K1 treatment Injectable vitamin K1 has no advantage over oral vitamin K1 and can cause anaphylaxis in some animals, even when injected subcutaneously A blood or plasma transfusion is indicated for animals that present with overt clinical signs (hemorrhage, dyspneic, pale).

Answer 366

b) Look for an occult infection somewhere else in the dog and perform blood cultures Look for an occult infection somewhere else in the dog and perform blood cultures. The dog has discospondylitis, which is usually caused by hematogenous spread of bacteria from a distant infected site. Radiography showing vertebral endplate lysis is definitive for a diagnosis, but blood cultures and sensitivities should be run to determine what type of antibiotics should be used. Surgery is usually indicated if neurologic deficits are severe. Bone scans are usually only used when radiographic changes are not yet visible.

Answer 367

d) Primary bone tumor The signalment of a large breed, older dog, and a radiographically aggressive bone lesion in the proximal humerus are most suggestive of primary bone neoplasia. The destructive element of the lesion indicates its aggression, and the location in one bone, in a site of predisposition for cancer, make fungal osteomyelitis less likely.

Answer 368

e. Excellent, \>95% of dogs recover This is a case of panosteitis based on the young age of the patient and radiographic presence of focal intramedullary densities within the humeral diaphysis. Minor differentials could include osteomyelitis. Panosteitis is a self-limiting, painful condition characterized by limping and lameness. It typically affects the long bones of young dogs, usually between the ages of 5 to 18 months. It can occur with any breed, but it is more common in medium- to large-sized dog breeds. Treatment is primarily supportive consisting of limiting activity and anti-inflammatory drugs. Pain lasts from weeks to months and resolves in nearly all cases. While these treatments reduce the pain associated with the condition, they may not alter the duration or course of the disease.

CANINES Flashcards

All about bitches! maybe not