FELINES Flashcards

Question

A 6-year old cat is brought to your clinic after falling off of the owner's balcony. The cat is stressed but alert with moderate bleeding noted around the mouth. Temperature - 102.4 F, 39.1 C Heart rate- 220 beats per minute, no murmurs or arrhythmias Respiratory rate- 40 breaths per minute, all lung fields clear Thoracic radiographs are unremarkable. You perform an oral exam and note the mandibular abnormality show in the photo. Which of the following treatment options is most appropriate once the cat is stable? a. Tape muzzle and conservative therapy b. Circummandibular cerclage wire placed caudal to canine teeth c. External fixator with 4 Kirschner wires d. Intramedullary pin placement in the mandibular canal Bone screw fixation across mandibular symphysis

Answer 1

b. Circummandibular cerclage wire placed caudal to canine teeth ## Footnote Separations of the mandibular symphysis are seen commonly with "high-rise syndrome" or when cats fall from heights because they frequently are able to rotate in mid-air, landing on all 4 feet to break the fall but often also landing with their lower jaw hitting the ground at the same time. This is sometimes referred to as a symphyseal fracture but it is not a true fracture as the mandibular symphysis never fully ossifies or fuses. Symphyseal separation occurs with this type of trauma and right and left rami become distracted as is evident in the photo. The standard treatment is circummandibular cerclage wire placed caudal to the lower canine teeth with the wire tightened once the hemi-mandibles are aligned. A hypodermic needle is often used to guide placement of the wire.

Answer 2

d. Placement of a esophagostomy tube with tube feeding ## Footnote The cat has hepatic lipidosis. This condition is often seen with obese cats that have become anorexic for several days, causing mobilization of excessive fat stores into the liver. Treatment is aimed at supplying nutrition to the cat to stop the cycle of fat being mobilized into the liver. The most effective way of doing this is with tube feedings. Prednisolone, antibiotics, insulin therapy and surgery are not warranted specifically with hepatic lipidosis, but may be effective in treating some of the causes that result in the cat becoming anorexic in the first place. Common causes for anorexia leading to hepatic lipidosis include inflammatory bowel disease, cholangiohepatitis, neoplasia, and pancreatitis.

Answer 3

a. Protein-losing nephropathy ## Footnote Enalapril is an angiotensin-converting enzyme (ACE) inhibitor used as a vasodilator, antihypertensive agent, and heart failure treatment. It works by preventing the conversion of angiotensin I to angiotensin II, thus reducing aldosterone concentrations and causing diuresis. Its dilatory effects on the efferent arterioles of glomeruli help to palliate protein losing nephropathies. It is often used in conjunction with diuretics.

Answer 4

c. 1-3 weeks from the end of the current estrus ## Footnote Estrus in cats, defined as the behavioral receptivity to mating, typically lasts about 7 days (usually between 4-10 days) Interestrus, the period between one estrus and the next, has a variable duration of 7-21 days. Cats are induced ovulators. If a queen ovulates but does not become pregnant, a psuedopregnancy occurs and corpora lutea develop and secrete progesterone. This inhibits GnRH release from the hypothalamus and secretion of LH and FSH from the anterior pituitary, preventing return to estrus (typically for 45-50 days). Additional clinical signs of pseudopregnancy are rare in cats.

Answer 5

d. Hyperadrenocorticism ## Footnote The correct answer is hyperadrenocorticism. Hyperadrenocorticism commonly occurs in DKA of dogs, but not in cats. Pancreatitis and bacterial infections commonly occur in DKA dogs and cats. Cardiac disease can be a common concurrent disease in a cat with DKA. Hyperthyroidism commonly occurs in DKA cats, but not dogs.

Answer 6

c. Confine the cat indoors for 5-7 days Explanation The history, onset, clinical appearance, as well as the cytologic and histologic findings are most consistent with insect bite hypersensitivity. There are other reasonable but less likely differentials including pemphigus foliaceus, food allergy or atopy, and dermatophytosis. The best way to rule in/out the most likely diagnosis is to confine the cat indoors and see if the lesions resolve as none of the other differentials would be expected to respond. It would be premature to institute skin testing for allergies or a dietary trial for food allergy. Aggressive flea control is not a bad idea, but the lesion distribution is less likely for flea allergy dermatitis. Cats are very sensitive to several pesticides. Bacterial culture would likely result in growth of normal superficial bacteria and not indicate the underlying pathology. It also may be necessary to initiate an anti-pruritic therapy to reduce further self-trauma by the cat.

Answer 7

d. CIsplatin ## Footnote The correct answer is cisplatin. The famed statement, "cis-plat splats cats" is quite appropriate. 5-fluorouracil is also contraindicated for use in cats, but it is neurotoxic. Carboplatin, vincristine and doxorubicin are all used in cats.

Answer 8

a. Normal to enlarged adrenal glands The clinical signs, patient's medical history, and lack of overt trauma is highly suggestive of skin fragility syndrome. Typically, these patients appear to have a normal looking coat from a distance but when palpated or manipulated one must be very careful, particularly when scruffing the patient. Skin fragility syndrome in cats is commonly associated with poorly regulated diabetes mellitus due to hyperadrenocorticism. Cushing's disease can cause insulin resistance. Clinical signs are similar to those seen in dogs (pendulous abdomen, polyuria, polydipsia, polyphagia, lethargy, and muscle wasting). The hyperadrenocorticism can be iatrogenic, adrenal dependent or pituitary dependent. In cats, approximately 80% have a pituitary tumor while 20% have an adrenal tumor. ACTH stimulation test is not recommended in cats due to poor sensitivity. The low dose dexamethasone suppression test is recommended to confirm hyperadrenocorticism. Urine cortisol-creatinine ratio can be used as a screening tool. The UCCR has a high sensitivity so a negative test makes Cushing's highly unlikely. Abdominal ultrasound can be used to support your diagnosis. With pituitary dependent Cushing's (which constitutes 80% of cats), you would expect normal to hypertrophied/enlarged adrenal glands. The excessive ACTH secreted from the pituitary gland produces an excessive amount of cortisol and adrenal hypertrophy. Bilateral adrenal atrophy can be seen with hypoadrenocorticism. A hypoechoic pancreas and hyperechoic mesentery is highly suggestive of pancreatitis which is not associated with fragile skin in cats. A hyperechoic liver and moderate hepatomegaly can be suggestive of hepatic disease such as hepatic lipidosis or lymphoma which would not result in fragile skin either.

Answer 9

c. Biopsy the lymph node and intestine and discuss a poor prognosis with the owner ## Footnote This cat most likely has Feline Infectious Peritonitis, or FIP, which is caused by a mutation of a feline corona virus. Fever, weight loss, and gastrointestinal symptoms are the most frequent presentation. However, this virus may attack multiple organs and can be difficult to diagnose; the only definitive way to diagnose this disease is via histopathology. Clinical symptoms, blood results, and corona virus titers can all be used in combination to help aid in the suspected diagnosis of FIP. Unfortunately, there is no cure for this disease and it is currently considered a fatal disease. Due to this cat's declining and critical health and strong evidence to support the diagnosis of FIP, euthanasia may be the most humane option. If the owner cannot be reached, however, it is the best option to go ahead and take biopsies while you are in surgery and then discuss the prognosis and differentials in detail when you can reach the owner. An animal should not be euthanized without owner consent. Inflammatory bowel disease should not cause ascites and fever. Parasites can lead to ascites, but typically would not cause the elevations of white blood cells and globulins with fever. While lymphoma may be a possibility, it is less likely in this young cat. The biopsies would help to differentiate.

Answer 10

d. Bovine insulin ## Footnote Feline insulin is closest in its amino acid sequence to bovine insulin, differing by only one amino acid in the A-chain. Canine insulin however is identical to porcine insulin in its amino acid sequence. It is quite dissimilar from feline insulin, differing by four amino acids. Feline and human insulin sequences differ by four amino acids. Although feline insulin is closest in sequence to bovine insulin, some cats can be managed quite well on other forms of insulin. Insulin glargine (Lantus), an engineered human insulin, is the current recommended insulin for cats. ProZinc (a protamine zinc recombinant human insulin) is also an option and has been FDA approved for use in diabetic cats. PZI (bovine zinc insulin) is no longer manufactured.

Answer 11

c. Toxoplasma ## Footnote In addition to the neutrophils seen cytologically, you should have seen toxoplasma gondii tachyzoites multiplying within macrophages and neutrophils. Cryptococcus is a narrow, budding, thin-walled yeast surrounded by a clear capsule. Streptococcus appears as small, round bacterial cocci. FIP effusion is typically characterized by a nonseptic exudate.

Answer 12

c. THey should be fed a regular commercial diet if eating ## Footnote The correct answer is feed a regular commercial diet if eating. Cats do not require a low-fat nor a low-protein diet and usually do not require a period of being NPO. Withholding food for an extended period may be likely to induce hepatic lipidosis in some cats. Additionally, some studies suggest that stimulation of pancreatic enzymes via feeding is actually necessary in affected cats. A jejunostomy feeding tube may be occasionally recommended in severe cases of pancreatitis with dogs, but is less likely necessary in cats. If anorectic, usually an esophagostomy feeding tube is sufficient.

Answer 13

c. Biopsy of the pad lesions This is a case of plasma cell pododermatitis which is a relatively uncommon idiopathic disorder of cats. While the history and description of the lesions is consistent with this uncommon disorder, other differentials could include pemphigus foliaceus, pemphigus vulgaris, or lupus erythematosus. A chemical or physical trauma could cause lesions such as these but do not fit well with the history. Neoplasia, infection, or sterile pyogranulomas are possible but would be unlikely to affect all paws simultaneously. Eosinophilic granuloma complex is also possible. Biopsy is likely the only way to differentiate between most of these possibilities. Because plasma cell pododermatitis is rare, it is unlikely that you would be asked about details of this disorder. With plasma cell pododermatitis, you would expect to see intense plasmacytic infiltration of the dermal tissue, potentially with other inflammatory cell types present due to secondary infection. The disease is not thought to have an infectious cause at this time. Treatment usually involves long courses (10 weeks) of Doxycycline. Approximately, 80% of cats will respond to Doxycycline. If a good response is not seen than systemic glucocorticoids can be tried. Surgical excision of the foot pad may be necessary in cases that fail to respond to medical management. Although this question involves a rare disease that you probably would not be expected to know very much about, the question itself involves critical thinking and clinical judgement that you should be able to reason through if you can construct an appropriate list of differential diagnoses. The ability to read through the details of a complicated case and identify the information needed to decide what to do next will be an important skill on your board exam.

Answer 14

b. Peri-operative analgesic use is imperative if onychectomy is performed The AVMA position statement on onychectomy states that declawing of domestic cats should be considered only after attempts have been made to prevent the cat from using its claws destructively or when its clawing presents a zoonotic risk for the owner. There are 7 specific points listed in the AVMA position statement as follows: 1. Scratching is a normal feline behavior, is a means for cats to mark their territory both visually and with scent, and is used for claw conditioning ("husk" removal) and stretching activity. 2. Owners must provide suitable implements for normal scratching behavior. Examples are scratching posts, cardboard boxes, lumber or logs, and carpet or fabric remnants affixed to stationary objects. Implements should be tall or long enough to allow full stretching, and be firmly anchored to provide necessary resistance to scratching. Cats should be positively reinforced in the use of these implements. 3. Appropriate claw care (consisting of trimming the claws every 1 to 2 weeks) should be provided to prevent injury or damage to household items. 4. Surgical declawing is not a medically necessary procedure for the cat in most cases. While rare in occurrence, there are inherent risks and complications with any surgical procedure including, but not limited to, anesthetic complications, hemorrhage, infection, and pain. If onychectomy is performed, appropriate use of safe and effective anesthetic agents and the use of safe peri-operative analgesics for an appropriate length of time are imperative. The surgical alternative of tendonectomy is not recommended. 5. Declawed cats should be housed indoors. 6. Scientific data do indicate that cats that have destructive clawing behavior are more likely to be euthanatized, or more readily relinquished, released, or abandoned, thereby contributing to the homeless cat population. Where scratching behavior is an issue as to whether or not a particular cat can remain as an acceptable household pet in a particular home, surgical onychectomy may be considered. 7. There is no scientific evidence that declawing leads to behavioral abnormalities when the behavior of declawed cats is compared with that of cats in control groups. Ref: AVMA position statement on the declawing of domestic cats - April 15, 2003 The only answer choice here that is in agreement with these points is that peri-operative analgesic use is imperative if onychectomy is performed. Scratching is considered a normal behavior and is not considered to be hormonally driven; therefore, castration is not likely to prevent further scratching.

Answer 15

b. Medial collateral ligament ## Footnote Disruption of the medial collateral ligament will lead to increased lateral give of the tarsal joint and a greater joint opening noted on the medial aspect. The reverse would be observed with a disruption of the lateral collateral ligament. The long digital extensor and the superficial digital flexor tendon do not play a role in stabilizing the tarsal joint.

Answer 16

d. Right heart failure ## Footnote The correct answer is right heart failure. HCM in cats usually only affects the left heart. Thromboemboli occur due to stasis of blood in the dilated left atrium. Left heart failure occurs as the left ventricle becomes stiffer, and blood backs up into the pulmonary vasculature. Systolic anterior motion of the mitral valve occurs when the anterior leaflet of the mitral valve blocks the left ventricular outflow tract during systole due to thickening of the ventricle wall and displacement of the valve leaflet.

Answer 17

c. Feline immunodeficiency virus The correct answer is feline immunodeficiency virus. The virus is shed in the saliva and is transmitted mainly through bites. The disease mostly affects older, outdoor male cats which have a higher likelihood of getting into fights and being bitten by other cats. Having the disease makes them immunosuppressed and more susceptible to infections. The remainder of the answer choices can be passed via passive contact.

Answer 18

a. Exploratory laparotomy to remove the ovarian remnant This is a classic description of ovarian remnant syndrome, which is when a cat goes into estrus after previously having an ovariohysterectomy (OVH). This can occur anywhere from weeks to years after OVH and typically the clinical signs consistent with estrus are sufficient to conclude that the cat is in estrus and has ovarian tissue present. Additional diagnostic tests that are consistent with ovarian remnant syndrome include: Serum estrogen \>70 pmol/L indicate that the cat has estrogen production from the ovary. The problem with this test is that estrogen measurements may fluctuate and can be unreliable. Serum progesterone \>6 nmol/L after induced ovulation is sufficient to conclude that corpora lutea formed and released progesterone. Testing for serum LH levels can also help confirm the diagnosis. In intact queens, LH is consistently maintained at basal levels due to negative feedback from ovarian estradiol secretion. After OVH, this control is lost and LH concentrations increase. LH \<1 ng/mL is consistent with the presence of an ovary as it is in this case. Surgery is the treatment of choice. Many practitioners prefer to do surgery during estrus or diestrus when the ovarian tissue is enlarged and easier to locate. Remnants may be bilateral so a complete exploratory laparatomy is necessary. Ovarian tissue is most commonly at the ovarian pedicle but can also be in the mesentery or elsewhere.

Answer 19

a. Persistent right aortic arch ## Footnote Persistent right aortic arch (PRAA) is reported but pretty rare in cats. It is seen more frequently in dogs, particularly a few predisposed breeds (Irish Setters, German Shepherds, Great Danes). Despite being a relatively uncommon disease, you should have been able to reach the appropriate answer by ruling out the other options because they cause different clinical signs. This is how PRAA develops: During fetal development, there is a right and left aortic arch. Normally the left aortic arch forms the main artery that extends off the heart and travels to the abdominal region. In cases of PRAA, the right aortic arch develops into the aorta and the esophagus becomes trapped by the ligamentum arteriosum that extends from the pulmonary artery to the aorta. There are several other variants of how the vascular anomaly can occur. Clinical signs commonly are present from a very young age, often near time of weaning. Treatment is surgical and the prognosis with early surgical intervention is good. Cats born with congenital diaphragmatic hernias often have mild breathing difficulties, especially when the cat is stressed. Sometimes they are incidentally diagnosed years later, although this is less common. In another presentation there may also be mild gastrointestinal upset. In severe cases, there can be respiratory distress, abnormal heart rhythm, muffled heart and lung sounds, and other signs of systemic shock. The abdomen may feel empty when palpated. Cats born with peritoneopericardial diaphragmatic hernia (PPDH) are usually asymptomatic with discovery being made when diagnostic tests (radiographs, contrast studies, ultrasound) are performed for other reasons. Occasionally, cats will develop vomiting, diarrhea, and abdominal pain or cardiorespiratory signs. Cats born with mucopolysaccharidosis (usually Siamese cats) have an enzyme deficiency that results in problems with the joints and/or bones. Cats born with myotonia congenita (very rare) have muscle stiffness and may be heavily muscled with little body fat.

Answer 20

e. Methocarbamol The correct answer is methocarbamol. Strychnine is found is some snail baits and other poisons. Strychnine competitively antagonizes the action of glycine and causes a loss of impulse control in the spinal cord and brainstem. Clinical signs can begin suddenly and progress from anxiety to tetanic convulsions spontaneously or in response to stimuli. The poison affects all striated muscles. There is no specific antidote, so treatment is symptomatic. Convulsions can be controlled with anesthetic drugs and/or methocarbamol. Stimulation should be prevented.

Answer 21

c. 50% chance of long term survival, 50% chance of dying within 3 months The case described is very consistent with acute cholangiohepatitis. This condition is usually seen in younger cats (mean age 3-3.5 years) and is more common in males than females. This is in contrast to chronic cholangiohepatitis which occurs in older cats (mean age 9 years). Acute cholangiohepatitis patients are more likely to be depressed, dehydrated and febrile. Bloodwork in cholangiohepatitis often shows a neutrophilia with or without a left shift. Mild increases in bilirubin and ALP are common, often with more severe elevations of ALT. The sonographic and biopsy findings are also consistent with the diagnosis of acute cholangiohepatitis and make other differentials such as hepatic lipidosis or lymphocytic portal hepatitis less likely. Treatment of choice for this disease includes antibiotics with aerobic and anaerobic coverage that are excreted unchanged in the bile. Examples of antibiotics excreted unchanged in the bile include tetracyclines, ampicillin, amoxicillin, erythromycin, chloramphenicol, and metronidazole. Usually erythromycin, tetracycline, and choloramphenicol are not the first choices unless they are indicated based on culture and sensitivity because erythromycin is not effective against gram negative bacteria, tetracycline is hepatotoxic, and chloramphenicol may cause anorexia. Ampicillin or amoxicillin with clavulanic acid are good choices and metronidazole may be used to expand the anaerobic coverage. Ursodeoxycholic acid (Actigall) is useful in all types of inflammatory liver disease because of its anti-inflammatory and anti-fibrotic properties on the liver. It also increases fluidity of biliary secretions. With treatment, it is thought that the response of acute and chronic cholangiohepatitis cases is similar with about half of animals dying or being euthanized within 90 days and half of them having prolonged survival.

Answer 22

a. Echocardiography and diuretic therapy The next step is to determine the type of cardiomyopathy causing the clinical signs and heart failure. The increased interstitial pattern in the cranioventral lung lobes indicates that there is cardiac decompensation. Diuretics are an appropriate therapy to treat heart failure pending diagnosis.

Answer 23

a. Full body lyme sulfur dip, itraconazole This cat has a ringworm infection caused by Microsporum canis. This fungi fluoresces blue under a Wood's lamp in 50% of cases. The best treatment for ringworm infection would include a combination topical and oral therapy. Lyme sulfur dip or an antifungal shampoo containing miconazole would be acceptable. Oral antifungals such as itraconazole or fluconazole are most effective with the least side effects. Povidone-iodine scrub has not been shown to be effective against ringworm. Lufenuron is classified as an insect development inhibitor because of its ability to inhibit chitin synthesis, thus in the past has been said to have some effect against fungal infections. This has been debated and not widely supported as a treatment for ringworm. Doxycycline is an antibiotic and would not be effective in treatment of fungal disease. Athlete's foot cream (clotrimazole) may have some effect at treating the lesion. Most over-the-counter creams such as this also include a steroid like betamethasone which would not be desired. Although this lesion appears to be localized to the nasal area, ringworm may also be subclinical and this cat may have infection elsewhere in the skin that is not grossly visible. Therefore, the best therapy is a combination of topical and oral.

Answer 24

a. Subtotal colectomy ## Footnote The correct answer is subtotal colectomy. This technique usually entails transecting the ascending colon a few centimeters distal to the cecum and the descending colon a few centimeters proximal to the pubis and anastomosing them together, trying to preserve the ileocolic junction. The other procedures listed are not successful therapies for megacolon.

Answer 25

c. Radical excision of the mass This is a probable vaccine associated fibrosarcoma. These tumors are slow to metastasize but extremely aggressive locally. A radical excision of the mass will be your best opportunity at a surgical cure. All other answer choices will likely result in poor margins and recurrence.

Answer 26

d. Migration of larvae to extopic regions (outside of the heart and pulmonary arteries) is less common than in dogs ## Footnote Cats do typically have fewer adult worms than dogs because of increased natural resistance. Cats are often microfilaria negative despite an active infection (either from all male worm infections, or occult disease). Antibody testing can detect exposure to both male and female worms; however, in cats, larvae are more likely to migrate to ectopic locations such as the brain, skin, and ocular tissue.

Answer 27

a. Serum ALT ## Footnote This cat has several classic features of hyperthyroidism. You might expect to find a palpable thyroid nodule as well. In addition to an elevated T4, clinicopathologic features of hyperthyroidism include erythrocytosis and a stress leukogram (neutrophilia, lymphopenia) due to increased circulating catecholamines. Increased catabolism of muscle tissue in hyperthyroid cats may result in increased BUN, but not creatinine. In fact, glomerular filtration rate (GFR) is increased in hyperthyroid cats, which may lower the BUN and creatinine and mask underlying renal insufficiency. Although hyperthyroidism increases GFR, the effect of thyroid hormone excess on the urinalysis can vary. Most cats, however, will have decreased urine specific gravity and may exhibit polyuria. The increased metabolic rate in hyperthyroidism results in liver hypermetabolism; therefore, serum activities of liver enzymes are commonly increased (ALT, ALP) in 80-90% of hyperthyroid cats. The increase in ALT is usually mild to moderate (100-400 IU/L). If the ALT is greater than 500, concurrent hepatic disease should be suspected. Serum cholesterol is usually normal, but can be moderately decreased, due to increased hepatic clearance mediated by thyroid hormones.

Answer 28

c. Progesterone Feline mammary hyperplasia, or fibroadenomatous hyperplasia, is a benign, often drastic enlargement of the mammary glands typically seen in younger cats. This syndrome classically has a rapid onset and is seen in pregnant and non-pregnant, unspayed females. It is uncommonly seen in males and spayed females. In cycling females, this condition is caused by hormonal stimulation from a functional ovary producing progesterone. Megesterol acetate is a synthetic progesterone that can cause this side effect. It is generally treated by ovariohysterectomy. If the mammary gland has become severely infected or ulcerated, a mastectomy may be required.

Answer 29

a. Pancreatic biopsy ## Footnote The correct answer is pancreatic biopsy. Amylase, lipase, and TLI are all unreliable indicators of pancreatitis in cats because they can be normal or elevated in cats with and without pancreatitis. The histologic appearance of pancreatitis in the cat is peripancreatic fat necrosis with acinar cell necrosis and inflammation. Although often impractical, pancreatic biopsy is the "gold standard" for diagnosing pancreatitis.

Answer 30

b. Herpesvirus infection ## Footnote The correct answer is herpesvirus infection. Herpesvirus is the only infectious cause of corneal ulcers in cats although they can become infected secondarily with bacteria. Herpes causes characteristic ulcers which are linear or sometimes referred to as dendritic ulcers. The lesions tend to be unilateral but can be bilateral. Usually, this is a persistent or recurrent disease that often flares up with stress.

Answer 31

b. Capillaria The correct answer is Capillaria. This is consistent with the clinical signs of cough. The peripheral eosinophilia could be caused by any of the parasites listed. Therefore, it is important to be able to recognize parasite eggs. Capillaria ova, as seen in the image, look similar to Trichuris eggs but are smaller and have asymmetric terminal plugs. Most cases of Capillaria are asymptomatic but chronic cough may be seen. Paragonimus is found by fecal flotation and have a single operculum. Aelurostrongylus larvae are recovered by Baermann.

Answer 32

b. Rivalta's test Of the tests listed, Rivalta's test has the highest negative predictive value in the diagnosis of FIP. This means that a negative test is likely associated with the cat truly not having the disease. In two separate studies, Rivalta's test has been shown to have a negative predictive value (NPV) greater than 90% (Hartmann 2003, JVIM: showed PPV=86% and NPV=97%, and Fischer 2012, Vet Clin Path: showed PPV=58% and NPV=93.4%). False positives are more commonly seen in older cats and cats with lymphoma or bacterial infections but negative results are relatively convincing compared to most other diagnostic tests for this disease. Rivalta's test involves filling a reagent tube with distilled water and 1 drop of acetic acid (98%). On the surface of this solution, 1 drop of the effusion fluid is added and if the drop disappears and the solution remains clear, the Rivalta's test is negative. If the drop retains its shape, stays attached to the surface, or slowly floats down to the bottom of the tube as a drop, Rivalta's test is defined as positive. The other tests listed tend to have high PPVs and are more specific but have more false negatives and are not as good for ruling out the disease. Reverse-transcriptase polymerase chain reaction (RT-PCR) for coronaviral RNA in serum has been reported to have a PPV= 90% and NPV= 47%. Coronavirus antibody detection in effusion has been reported to have a PPV= 90% and NPV= 79%. Immunofluorescence staining for coronavirus in macrophages in effusion fluid has been reported to have a PPV= 100% and NPV= 57%.

Answer 33

c. Superficial skin scrape The key to this question lies in realizing that the cat most likely has Demodex gatoi since this is the only Demodex species that is contagious. Also Demodex gatoi is often very itchy. Demodex gatoi differs from Demodex cati in that it infects the epithelium and not the hair follicle. Thus, the best test would be a superficial skin scrape. The best diagnostic test for Demodex cati would be a deep skin scrape. A trichogram refers to analyzing hair and is a useful test for dermatophytes and follicular mites. A bacterial culture may be indicated if you have a secondary infection. A fungal culture is not useful for Demodex.

Answer 34

d. 2 First, you must recognize that the cat's weight is given in pounds and should immediately be converted to kilograms. There are 2.2 lbs/kg so this is a 10 kg cat. Second, you must be able to convert a percent solution to mg/ml. A 2.5% solution is 25 mg/ml. This is hard for some students to remember. A memory tip is that a 100% solution would be 1 gram/ml. Therefore a 50% solution would be 500mg/ml, and a 5% solution would be 50 mg/ml. The math to solve this question is: 22 lbs x (1 kg/2.2 lbs) x 5mg/kg x (1ml/25mg) = 2 ml

Answer 35

d. Diazepam ## Footnote Diazepam is a benzodiazepine sedative that has been used effectively for appetite stimulation in cats, but administration has been associated with acute fulminant hepatic necrosis. The risk appears to be greatest if diazepam is administered repeatedly and orally. This side effect is thought to be related to metabolism of the drug in the liver to toxic metabolites. This is more severe when administered orally due to first pass metabolism. Cats that are glutathione deficient may be at increased risk. The other drugs listed have not been associated with this type of liver failure in cats. Omeprazole is a proton-pump inhibitor that is used to decrease gastric acid secretion. A potential side effect is an increase in liver enzymes but this is not thought to be harmful.

Answer 36

d. A large percentage of cats are seropositive for Toxoplasma gondii, but are not necessarily shedding oocysts The correct answer is a large percentage of cats are seropositive for Toxoplasma gondii but are not necessarily shedding oocysts. Infected cats will usually only shed oocysts for 1-2 weeks when they are initially infected. They usually don't shed again unless they become severely immune-compromised. Paired serum titers should be taken 1-2 weeks apart in order to determine the stage of infection. A rise in the consecutive titers would mean the cat was recently infected. Titers that aren't significantly different can be interpreted as the cat having an old infection and is less likely to be actively shedding oocysts. Infectivity of the oocysts occurs with sporulation, which occurs within 1-5 days after shedding.

Answer 37

d. Echocardiography and diuretic therapy The next step is to determine the type of cardiomyopathy causing the clinical signs and heart failure. The increased interstitial pattern in the cranioventral lung lobes indicates that there is cardiac decompensation. Diuretics are an appropriate therapy to treat heart failure pending diagnosis.

Answer 38

b. Initial treatment response Feline leukemia virus seropositive and seronegative cats share similar response rates to initial treatment with chemotherapy for lymphoma. However, survival times are shorter for cats with FeLV compared with FeLV negative cats. Most U.S. cats with mediastinal, multicentric, or spinal forms of lymphoma are FeLV-positive

Answer 39

e. Humalin-R (regular insulin) ## Footnote This cat is in a state of diabetic ketoacidosis. Due to this status, the recommended insulin type is Humulin-R, or regular insulin. This is a shorter acting insulin which will help to get the ketonuria to resolve more efficiently. After the ketosis has resolved and the cat is hydrated, eating, drinking, and electrolytes are stable, the cat can be switched to a longer acting insulin. Glargine or PZI are the insulin types of choice for long term control in felines after the ketoacidosis has been corrected, but other insulin types can also be used.

Answer 40

b. Chronic pancreatitis ## Footnote The correct answer is chronic pancreatitis. This is the case in cats, in contrast to dogs, which develop EPI from pancreatic acinar atrophy.

Answer 41

a. This effusion is strongly suggestive of FIP ## Footnote The correct answer is that this effusion is strongly suggestive of FIP. FIP causes a classic straw or gold colored effusion with high protein content (about equal to serum protein) and moderate cell counts. An exudate would tend to have somewhat higher cell counts and lower protein. The protein content is not consistent with chyle or neoplasia.

Answer 42

b. Thoracocentesis ## Footnote If a cat presents with rapid shallow breathing, quiet lung sounds, and a heart that auscults normally, pleural space disease, including effusion or pneumothorax, is the most likely cause of the breathing pattern. Various types of pleural effusion include blood (hemothorax) which could result from trauma or coagulopathy, pus (pyothorax) which could be caused by a migrating foreign body or other infection in the pleural space, chyle (chylothorax) which occurs from unknown causes or a ruptured thoracic duct, other neoplastic effusions (such as lymphoma), or infection (such as FIP). If the chest tap is positive, thoracocentesis should be completed in an attempt to stabilize the animal's respiratory status before taking radiographs. The only case in which the fluid should not be removed is hemothorax, if an active bleed into the pleural space is suspected. Cytology and analysis of the fluid collected will be helpful in the diagnosis; it is not always possible to tell the cause of the effusion by gross observation. In pets that are in distress, it is best to take a dorsoventral radiograph instead of a ventrodorsal view since placing them on their back can cause further distress and could potentially lead to respiratory arrest. Cats in congestive heart failure may have crackles on auscultation and often have a heart murmur or gallop rhythm. Diaphragmatic hernia typically has the same breathing pattern, but usually the lung sounds are not as quiet as they are with effusions. A barium swallow would not be performed first in this case; stabilizing the patient always comes first. If a diaphragmatic hernia were suspected, the patient should be held upright to try and keep the abdominal organs from invading the chest cavity.

Answer 43

b. Arachidonic acid ## Footnote The correct answer is arachidonic acid. Cats, unlike dogs, require intact arachidonic acid in their diets.

Answer 44

b. The cat has primary metabolic acidosis with compensatory respiratory alkalosis The correct answer is that the cat has primary metabolic acidosis with compensatory respiratory alkalosis. The low pH tells you the cat is acidemic so the primary disorder must be an acidosis because compensatory mechanisms will never overshoot the primary abnormality. In this case, the negative base excess or low HCO3 tells us there is a metabolic acidosis (renal disease can cause this). The low PaCO2 tells us there is a respiratory alkalosis or hyperventilation. The primary abnormality must be the metabolic acidosis. The respiratory alkalosis can then be interpreted as compensatory.

Answer 45

c. MRI of the brain ## Footnote This cat has clinical signs most consistent with acromegaly (weight gain, prognathism, organomegaly, and diabetes mellitus that is difficult to control). This condition results from a growth hormone (GH) secreting pituitary tumor. GH or insuline-like growth factor (IGF) assays can be diagnostic but are not offered by many veterinary laboratories. Advanced imaging techniques are the most reliable way to diagnose a pituitary mass in this instance. This cat is not likely to be hyperthyroid due to the history of weight gain. Hyperadrenocorticism as a cause of insulin-resistant diabetes mellitus is less likely given the cat's other clinical signs; nevertheless, adrenal function testing such as an ACTH stimulation test or dexamethasone suppression test to rule out hyperadrenocorticism should be considered.

Answer 46

a. Black widow spider bite The correct answer is black widow spider bite. Latrodectus mactans and L. hesperus are the scientific names for this spider. They make a toxin that binds to calcium channels, increasing membrane permeability and enhancing depolarization. Ascending motor paralysis and destruction of peripheral nerves endings occur. A single bite may be serious to adult humans and could kill a small animal. Clinical signs occur almost immediately with pain, due in part to the release of acetylcholine, which stimulates contraction of major muscle groups. There may be ascending motor paralysis, muscle spasms, muscle rigidity, and salivation. Death from respiratory or cardiovascular failure is possible.

Answer 47

c. A mixed pleocytosis and elevated protein on CSF analysis with no bacteria The correct answer is a mixed pleocytosis and elevated protein on CSF analysis with no bacteria. Demonstration of the organism, visible as small yeasts surrounded by a large capsule is occasionally seen with Cryptococcus. Serology is also very useful for diagnosis. The latex agglutination test against the cryptococcal antigen is very sensitive and specific and can be used to document disease or monitor therapy. It can be run on serum, CSF, or urine. A mixed pleocytosis is common in many conditions causing CNS signs and is not specific for any of them.

Answer 48

c. Tap both side of the chest to evacuate as much fluid as possible ## Footnote The radiographs describe significantly rounded lung lobes which suggests that the fluid has caused some fibrosing pleuritis. Sheets of fibrous connective tissue often times will cause pocketing of fluid on the right and left sides of the chest. Thus, it is important to tap both sides of the chest to adequately drain enough fluid to relieve dyspnea. The immediate life-saving procedure will be to remove the fluid that is causing the respiratory distress. Chylothorax is usually idiopathic in origin and rarely may resolve spontaneously in 1-2 months. Most cases ultimately require surgery which is usually a combination of ligation of the thoracic duct and a sub-total pericardiectomy.

Answer 49

c. Striated muscle ## Footnote The correct answer is striated muscle. Rhabdomyosarcomas, by definition are tumors derived from striated (or skeletal) muscle.

Answer 50

a. Basal cell tumor ## Footnote The correct answer is basal cell tumor. This is the most common skin tumor in the cat (about 20% of all feline skin tumors). These tumors are usually hairless, dome-shaped, raised masses as described. They are most frequently found on the head, neck, and shoulders. They are almost always benign although histologically, they may have aggressive characteristics.

Answer 51

c. Cutaneous feline mast cell tumors are most commonly found on the trunk and extremities ## Footnote Cutaneous feline mast cell tumors are most commonly located on the face and head. They are the second most common skin tumor found in cats, behind basal cell tumors. Feline mast cell tumors of the skin rarely metastasize. Generally speaking, when metastatic mast cell disease is found, it is likely that a visceral source of disease (i.e. splenic mast cell disease) is present. Feline mast cell tumors of the skin are not graded as they are in dogs, but histopathology is relied upon to dictate the behavior of the tumor that is removed.

Answer 52

c. Ovariohysterectomy The cat in the image has mammary gland hyperplasia or fibroadenomatous/fibroepithelial hyperplasia. It most commonly occurs in young, intact female cats due to increased progesterone exposure. It is characterized by affecting one or more mammary glands, which become enlarged and are non-painful. Most affected cats are systemically well and do not show signs of illness or pain. Treatment for the condition is removal of the source of progesterone via ovariectomy or ovariohysterectomy. If no source of progesterone can be identified, or if the glands do not respond to spaying, a progesterone receptor blocker such as aglepristone can be administered as well. Differential diagnoses for this condition include mammary neoplasia and mastitis. Mammary cancer more commonly affects older cats and would be less likely to affect all glands simultaneously and symmetrically like the cat shown in the picture. Mastitis would be painful, inflamed, and the cat would likely be acting systemically ill.

Answer 53

d. Defect in collagen production ## Footnote Ehlers-Danlos syndrome is a hereditary condition in which a defect in collagen production results in abnormal Type I collagen. This renders the skin very pliable, thin, and susceptible to trauma. Patients with this condition should not be bred. Treatment consists of appropriate housing and lifestyle modifications and prompt treatment of secondary infections. Cats with hyperadrenocorticism may develop a similar skin fragility syndrome, which as the name implies, results in a very thin, easily damaged, friable skin. Uric acid deposition within joints is known as gout. There is no known condition in which deposition in skin associated collagen causes these clinical signs.

Answer 54

a. Gastrointestinal parasites ## Footnote The correct answer is gastrointestinal parasites. You should perform a fecal float and smear. This cat probably has severe diarrhea and has been straining. Dysautonomia is possible but very rare. Panleukopenia does not usually result in a rectal prolapse, but is a cause of diarrhea.

Answer 55

b. Exploratory laparotomy with linear foreigh body removal Linear foreign bodies are surgical emergencies. The string is often anchored at the base of the tongue. The peristaltic activity of the stomach and intestines around a string causes bunching of the intestines. With peristaltic movement, the string will often saw through the intestines, leading to perforation and peritonitis. Induction of emesis, endoscopy, or release of the string would be unlikely to relieve the bunching of the intestines.

Answer 56

c. Naloxone ## Footnote The correct answer is naloxone. Butorphanol can also be used to reverse mu agonists like oxymorphone (but it wasn't in the list of choices). It is a partial mu antagonist, kappa agonist. Morphine is a mu agonist and would have a similar effect on the cat as oxymorphone. Buprenorphine is a partial mu agonist, kappa antagonist and would not effectively reverse the effects of pure mu agonists. Yohimbine is used to reverse alpha 2 agonists such as xylazine. Naloxone is the only opioid antagonist amongst the choices that can be used to effectively reverse the mu agonists.

Answer 57

a. Otic exam Any dog or cat that presents with vestibular signs such a head tilt, nystagmus, and circling should have an otic exam as part of its physical exam. Vestibular disease can be central or peripheral in origin. Although, advanced imaging such as a MRI or CT scan of the head is often recommended for vestibular disease to better characterize the brain and inner ear, an otic exam is the least invasive way to evaluate the patient and should be the next step, even prior to running blood work. Also, it is important to check blood pressure in an animal presenting with vestibular disease. Hypertension and vascular accident can be an important cause to rule out. It is a good idea to get the blood pressure before you draw the blood to minimize stress during the blood pressure readings.

Answer 58

b. Methylprednisolone injection (Depo Medrol/corticosteroid) In cats with an undiagnosed heart murmur, a corticosteroid (especially Depo Medrol) is generally not a good idea. It has been theorized that cats with underlying heart disease, whether or not they have a heart murmur, can be pushed into congestive heart failure by administration of steroids. One theory is that the mineralocorticoid effect can cause fluid retention leading to overload and congestive heart failure. Another is plasma volume expansion as a result of an intra- to extracellular fluid shift that occurs due to glucocorticoid-mediated extracellular hyperglycemia. Clavamox in general is a good antibiotic for skin infections or abscesses in cats. Chlorpheniramine or antihistamine may help the cat with pruritus and would be acceptable for treating allergies in general. A hypoallergenic diet may help this cat if the allergy had a food component (which is less likely with seasonal allergies), but certainly would not be contraindicated.

Answer 59

b. IV administration of calcium gluconate ## Footnote Calcium gluconate will serve to immediately counter the effects of hyperkalemia-induced bradycardia and cardiovascular collapse in this cat with a most-likely diagnosis of urethral obstruction. The other interventions will help to reduce the level of potassium and could be a part of therapy but may not take effect rapidly enough to address the most life-threatening component of the cat's illness.

Answer 60

a. Baermann fecal technique ## Footnote The correct answer is Baermann fecal technique. Strongyloides stercoralis mainly causes a mucoid diarrhea and possibly anemia in puppies and kittens. It passed in the feces in the L1 larvae form. The best technique for recovering larvae is the Baermann technique. Fecal flotations are good for eggs that float. Fecal sedimentation is good for eggs that sink, such as most fluke eggs. A direct fecal smear can find any type of egg or larva passed in feces but does not concentrate the sample to improve the yield in finding the eggs or larvae.

Answer 61

e. Quarantine the cat for 10 days, or euthanize it and test it for rabies The best answer is to quarantine for 10 days, or euthanize it and test it for rabies. You may confine the cat and observe it for 10 days if it is vaccinated.

Answer 62

b. Superficial skin scrape The key to this question lies in realizing that the cat most likely has Demodex gatoi since this is the only Demodex species that is contagious. Also Demodex gatoi is often very itchy. Demodex gatoi differs from Demodex cati in that it infects the epithelium and not the hair follicle. Thus, the best test would be a superficial skin scrape. The best diagnostic test for Demodex cati would be a deep skin scrape. A trichogram refers to analyzing hair and is a useful test for dermatophytes and follicular mites. A bacterial culture may be indicated if you have a secondary infection. A fungal culture is not useful for Demodex.

Answer 63

d. The clinical signs are likely due to flea allergy dermatitis and flea treatment is necessary ## Footnote The correct answer is that you are suspicious of flea allergy dermatitis and flea treatment is necessary. In warmer climates, flea allergies can be seen year-round. And like other allergic disorders, flea allergy dermatitis can also be progressive. It is not surprising that fleas or flea excrement were not detected. Animals, particularly cats, who are pruritic typically either scratch or lick off the fleas and their excrement. The clue that suggests flea allergy dermatitis is that the cat has miliary dermatitis and is not on any flea control. However, the cat may also have a food and/or environmental allergy. Flea treatment should be considered before work-up of food or environmental allergies, since a work-up can be lengthy and expensive. Steroids can be used to treat flea allergy dermatitis, but this is only palliative therapy and should be used with appropriate flea medication.

Answer 64

d. Pancreatic biopsy ## Footnote The correct answer is pancreatic biopsy. Amylase, lipase, and TLI are all unreliable indicators of pancreatitis in cats because they can be normal or elevated in cats with and without pancreatitis. The histologic appearance of pancreatitis in the cat is peripancreatic fat necrosis with acinar cell necrosis and inflammation. Although often impractical, pancreatic biopsy is the "gold standard" for diagnosing pancreatitis.

Answer 65

c. IV administration of calcium gluconate ## Footnote Calcium gluconate will serve to immediately counter the effects of hyperkalemia-induced bradycardia and cardiovascular collapse in this cat with a most-likely diagnosis of urethral obstruction. The other interventions will help to reduce the level of potassium and could be a part of therapy but may not take effect rapidly enough to address the most life-threatening component of the cat's illness.

Answer 66

b. Surgery ## Footnote The radiographs show the colon in the thoracic cavity. This finding is consistent with a diaphragmatic hernia. The best course of treatment is surgery to return the abdominal organs back into their appropriate place and close the defect in the diaphragm. Note that the cat has an increased respiratory rate, due to the colon being in the chest.

Answer 67

b. Pyelonephritis ## Footnote The correct answer is pyelonephritis. Pollakiuria and dysuria are lower urinary tract signs that are not consistent with pyelonephritis alone. Pyelonephritis causes systemic signs such as fever, anorexia, and depression.

Answer 68

a. Black widow spider bite The correct answer is black widow spider bite. Latrodectus mactans and L. hesperus are the scientific name for this spider. They make a toxin that binds to calcium channels, increasing membrane permeability and enhancing depolarization. Ascending motor paralysis and destruction of peripheral nerves ending occur. A single bite may be serious to adult humans and could kill a small animal. Clinical signs occur almost immediately with pain, dur in part to the release of acetylcholine, which stimulates contraction of major muscle groups. There may be ascending motor paralysis, muscle spasms, muscle rigidity, and salivation. Death from respiratory or cardiovascular failure is possible.

Answer 69

b. Vomiting The correct answer is vomiting. Xylazine frequently causes vomiting in cats. In fact, veterinarians use Xylazine when they wish to induce emesis in cats. It can also cause decreased PCV, mydriasis, and diuresis.

Answer 70

d. Exploratory laparotomy to remove the ovarian remnant This is a classic description of ovarian remnant syndrome, which is when a cat goes into estrus after previously having an ovariohysterectomy (OVH). This can occur anywhere from weeks to years after OVH and typically the clinical signs consistent with estrus are sufficient to conclude that the cat is in estrus and has ovarian tissue present. Additional diagnostic tests that are consistent with ovarian remnant syndrome include: Serum estrogen \>70 pmol/L indicate that the cat has estrogen production from the ovary. The problem with this test is that estrogen measurements may fluctuate and can be unreliable. Serum progesterone \>6 nmol/L after induced ovulation is sufficient to conclude that corpora lutea formed and released progesterone. Testing for serum LH levels can also help confirm the diagnosis. In intact queens, LH is consistently maintained at basal levels due to negative feedback from ovarian estradiol secretion. After OVH, this control is lost and LH concentrations increase. LH \<1 ng/mL is consistent with the presence of an ovary as it is in this case. Surgery is the treatment of choice. Many practitioners prefer to do surgery during estrus or diestrus when the ovarian tissue is enlarged and easier to locate. Remnants may be bilateral so a complete exploratory laparatomy is necessary. Ovarian tissue is most commonly at the ovarian pedicle but can also be in the mesentery or elsewhere.

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