NAVLE Mock Test Flashcards
A7-year old female spayed English Springer Spaniel presents for difficulty breathing and lethargy. Physical exam shows pale mucous membranes and increased respiratory effort. You collect blood for a complete blood count and a chemistry panel and you place a drop of blood with a drop of saline on a glass slide. After swirling the sample around, you can grossly see what is shown in the picture. What’s your diagnosis?
Immune mediated hemolityc anemia.
The image shows a positive slide agglutination test. The dark patches in the sample are caused by antibodies attached to the surface of the erythrocytes cross linking the cells together causing these clumps. This is highly suggestive of an immune mediated reaction to antigen on the individual’s red blood cells.
Rouleaux formations are red blood cells stacked together as a result of their natural discoid shape and large surface area causing them to have an affinity for each other. They typically resemble a stack of coins or cookies.
Evan’s syndrome is an autoimmune condition characterized by an immune attack on erythrocytes, platelets, and occasionally leukocytes as well. You would not be able to diagnose this on a slide agglutination test alone.
What is the primary mode of transmission of West Nile Virus (WNV) between birds?
Via mosquitoes.
Mosquito vectors are the primary mode of transmission for WNV between birds and other hosts (horses, humans). There are infrequent documented cases of the disease being spread by feces or saliva. No mites have been documented to transmit the disease. Birds do not have a placenta.
A 12-year old male neutered domestic short hair cat presents for ongoing evaluation of diabetes mellitus. The cat was diagnosed 6 months ago and has continued to be markedly polyuric, polydipsic, polyphagic, and has been gaining weight. The cat is currently receiving 10 units of glargine insulin every 12 hours. On physical exam, the cat weighs 15 pounds (6.8 kg) and has an enlarged head, abdomen, and paws. What imaging modality would be most appropriate to try and prove what you suspect is causing the uncontrolled diabetes and weight gain in this cat?
Magnetic resonance imaging (MRI) of the head.
This cat has the signs and symptoms of acromegaly. Acromegaly is caused by excessive growth hormone release from the pars distalis from a tumor in the pituitary gland. Excessive growth hormone causes a defect in the insulin receptors on target cells causing insulin resistant diabetes mellitus.
The enlarged head, paws, abdomen, and weight gain despite uncontrolled diabetes is due to the anabolic effects of the growth hormone.
Treatment for this condition includes radiation therapy to the pituitary tumor, high doses of insulin to try and control the diabetes, and somatostatin analogs (octreotide) to try and inhibit the release of growth hormone from the tumor. Surgical excision has been used as a form of treatment in people with pituitary tumors, but this has only been rarely reported in cats.
A 2-year old mare presents to you several weeks after recovering from a mild upper respiratory infection. She now presents with edema and sloughing of the legs, chest and abdomen as well as mucosal petechial hemorrhages. She is sore and reluctant to move. Biopsy of the skin lesion is consistent with aseptic necrotizing vasculitis. What is the most likely diagnosis?
Purpura hemorrhagica.
This is the clinical and histologic appearance of purpura hemorrhagica. It is a type-Ill hypersensitivity which is when antigen-antibody complexes accumulate, leading to disease.
Purpura hemorrhagica most commonly occurs 2-4 weeks after exposure to certain infectious agents or vaccines. This condition is most commonly seen subsequent to infection with Streptococcus equi subsp. equi or vaccination against it but it can also be associated with other pathogens, particularly respiratory pathogens including other streptococcal species and equine influenza.
Regardless of the cause, purpura hemorrhagica results from accumulation of antigen-antibody complexes that deposit on blood vessel walls and activate a strong immune response (vasculitis). The leaky blood vessels lead to hemorrhage and edema.
Bastard strangles refers to the condition when Streptococcus equi subsp. equi creates abscesses in unusual sites (other than the lymph nodes draining the throat) such as abdominal or lung lymph nodes.
Cantharidin toxicity (also known as blister beetle toxicity) leads to mucosal irritation and results in colic and cystitis. It can also lead to hypocalcemia.
Primary immune-mediated thrombocytopenia (sometimes called idiopathic thrombocytopenia) can be seen in horses but is not consistent with the necrotizing vasculitis described in the case.
Type I hypersensitivity reactions are immediate reactions (such as urticaria) invoked by an antigen or allergen.
A pregnant mare was brought out to your barn for observation in anticipation of parturition. After several hours of restless behavior, several gallons of allantoic fluid rush out from the vulva. Which of the following would you expect to happen next for a normal parturition?
The thin, white, glistening amniotic membrane emerges from the vulva.
This case description is consistent with stage I of labor in the horse. The first stage of foaling typically lasts 30 minutes to 4 hours. During this stage, mares act restless and may exhibit signs similar to colic such as flank watching, pawing, and constantly getting up and down. When the placenta ruptures (“water breaks”), there may be several gallons of allantoic fluid that come out. Usually, within about 5 minutes, the second stage of labor begins and the foals feet and nose appear at the vulva, covered in the white, thin, glistening amnion. If a red, velvety, membrane is seen, this is the chorioallantois which indicates premature placental separation which can impair oxygen delivery to the fetus and can result in death of the foal. Usually, the muzzle will emerge from the amnion by the time the foal’s hips pass through the pelvis but if not, the amnion can be gently broken and removed. Usually, the umbilical cord breaks naturally when the mare stands or foal begins to rise. Then, within 30 minutes to 3 hours after foaling, the placenta should be expelled.
A 2-year old male neutered cat presents to you depressed, hypersalivating, and ataxic with muscle tremors. The owner reports that a pyrethrin-based spot-on formulation for flea control belonging to their Golden Retriever was accidentally applied on the cat earlier today. Which of the following drugs will you use to treat the cat’s clinical signs?
Methocarbamol.
Pyrethrins alter the activity of the sodium ion channels of nerves, which prolongs the period of sodium conductance. This increases the length of depolarization resulting in repetitive nerve firing. Cats are particularly sensitive to pyrethrin-containing products and can develop clinical signs within hours after administration. Affected animals should be bathed to remove remaining product. Minor clinical signs such as hypersalivation and ear twitching are usually self-limiting and do not require treatment. Control of marked tremors or seizures can be achieved with methocarbamol (Robaxin).
A 4-year old male Manx cat presents to you because the owners found an empty, opened pill vial in the bathroom and the cat vomited. On physical exam, you note ptyalism and facial edema. The cat’s mucous membranes are pale and slightly icteric. You perform a blood smear and detect Heinz bodies in erythrocytes. The cat’s packed cell volume (PCV) is 26% (30-45%). The owners provide you a list of the medications in the medicine cabinet which are acetaminophen (Tylenol), finasteride (Propecia), enalapril (Vasotec), and omeprazole (Prilosec). What treatments should you institute for this cat?
Acetylcysteine and S-adenosylmethionine.
Acetaminophen toxicity in cats usually occurs when owners administer the drug, unaware of its significant potential toxicity in cats. In this case, the cat’s clinical signs are most consistent with acetaminophen toxicity based on the Heinz body anemia that is present. Cats can die from oxidative damage and methemoglobinemia within 1-2 days of ingestion. It may also be associated with hepatotoxicity in cats, although this is seen more frequently in dogs.
Recall that cats are particularly sensitive to acetaminophen because they have decreased glucuronyl transferase activity which conjugates acetaminophen to glucuronic acid for excretion. As a result, 50-60 mg (a single tablet) may be fatal for a 4-5 kg cat.
Treatment should consist of toxin removal if possible by inducing emesis in some cases. As the cat in this case is already vomiting, this may not be necessary. Activated charcoal is controversial and should only be given if ingestion occurred within hours and should be administered very carefully in cats due to the risk of aspiration.
The specific antidote is acetylcysteine which binds to some of the reactive metabolites of acetaminophen and increases the availability and synthesis of glutathione. Other treatments may include S-Adenosylmethionine (SAMe) which has hepatoprotective and antioxidant properties. Cimetidine can be given to inhibit the p450 oxidase in the liver and limit formation of toxic metabolites. Ascorbic acid can also be used as an adjunct treatment to bind toxic metabolites. In cats with signs of hypoxemia from severe hemolytic anemia (PCV <20%), a transfusion and further supportive care may be warranted.
Your client is pregnant and is worried about acquiring toxoplasmosis from her cat. What do you advise?
Have a housemate empty the litter box daily as a simple precaution to prevent infection as it takes 1-3 days for passed oocysts in the stool to sporulate into an infective form.
Toxoplasmosis gondii is a protozoal organism. The cat is the definitive host; the entire life cycle of the organism can be completed within this host. Most cats become infected when they consume an exposed rodent with bradyzoites encysted in their tissues. Only recently infected cats generally shed oocysts in their stool, and cats typically only shed these oocysts for 1-2 weeks. Most cats will only have one shedding episode in their lifetime.
A IgM (not IgG) titer of 1:64 or greater suggests recent or active infection and that cat is at risk of shedding oocysts in their stools. Oocysts are not infective until they sporulate. This process takes > 24 hours, so emptying the litter box daily is advised, preferably by someone who is not pregnant.
If an owner has owned cats for a long while, it is possible that they may have previously been exposed and therefore have mounted an immune response to the organism. If so, it may be advisable to test for Toxoplasma antibody titers in the owner. A sufficient antibody titer will mean the client is protected from infection during the first trimester.
A 2-year old male neutered cat presents to you depressed, hypersalivating, and ataxic with muscle tremors. The owner reports that a pyrethrin-based spot-on formulation for flea control belonging to their Golden Retriever was accidentally applied on the cat earlier today. Which of the following drugs will you use to treat the cat’s clinical signs?
Methocarbamol.
Pyrethrins alter the activity of the sodium ion channels of nerves, which prolongs the period of sodium conductance. This increases the length of depolarization resulting in repetitive nerve firing. Cats are particularly sensitive to pyrethrin-containing products and can develop clinical signs within hours after administration. Affected animals should be bathed to remove remaining product. Minor clinical signs such as hypersalivation and ear twitching are usually self-limiting and do not require treatment. Control of marked tremors or seizures can be achieved with methocarbamol (Robaxin).
A 4-year old male Manx cat presents to you because the owners found an empty, opened pill vial in the bathroom and the cat vomited. On physical exam, you note ptyalism and facial edema. The cat’s mucous membranes are pale and slightly icteric. You perform a blood smear and detect Heinz bodies in erythrocytes. The cat’s packed cell volume (PCV) is 26% (30-45%). The owners provide you a list of the medications in the medicine cabinet which are acetaminophen (Tylenol), finasteride (Propecia), enalapril (Vasotec), and omeprazole (Prilosec). What treatments should you institute for this cat?
Acetylcysteine and S-adenosylmethionine
Acetaminophen toxicity in cats usually occurs when owners administer the drug, unaware of its significant potential toxicity in cats. In this case, the cat’s clinical signs are most consistent with acetaminophen toxicity based on the Heinz body anemia that is present. Cats can die from oxidative damage and methemoglobinemia within 1-2 days of ingestion. It may also be associated with hepatotoxicity in cats, although this is seen more frequently in dogs.
Recall that cats are particularly sensitive to acetaminophen because they have decreased glucuronyl transferase activity which conjugates acetaminophen to glucuronic acid for excretion. As a result, 50-60 mg (a single tablet) may be fatal for a 4-5 kg cat.
Treatment should consist of toxin removal if possible by inducing emesis in some cases. As the cat in this case is already vomiting, this may not be necessary. Activated charcoal is controversial and should only be given if ingestion occurred within hours and should be administered very carefully in cats due to the risk of aspiration.
The specific antidote is acetylcysteine which binds to some of the reactive metabolites of acetaminophen and increases the availability and synthesis of glutathione. Other treatments may include S-Adenosylmethionine (SAMe) which has hepatoprotective and antioxidant properties. Cimetidine can be given to inhibit the p450 oxidase in the liver and limit formation of toxic metabolites. Ascorbic acid can also be used as an adjunct treatment to bind toxic metabolites. In cats with signs of hypoxemia from severe hemolytic anemia (PCV <20%), a transfusion and further supportive care may be warranted.
What is the potential udder fate of goats infected with caprine arthritis encephalomyelitis virus?
Hardbag.
CAEV is a retrovirus and when it affects the udder it will cause fibrosis and result in a firm udder with agalactia. Treatment is ineffective and the goat should be culled. The disease is usually subclinical but can cause arthritis in adults and encephalitis in kids.
You are asked to examine some feeder pigs that have stopped eating yesterday. The group is lying down and seems lethargic. They have fevers of 105-106F (40.6 -41.1 C), firm dry feces, and the skin has rhomboid-shaped red blotches scattered on it. What treatment should be recommended?
Penicillin.
Erysipelas is susceptible to penicillins, as well as tetracyclines (usually), lincomycin and tylosin. Chloramphenicol and nitroimidazoles (including metronidazole) are not approved for food animal use.
A horse presents to you for chronic, recurrent laminitis and skin disease. You notice on your exam that the horse has a particularly thick, long, wavy, and matted coat. The owner mentioned that this developed many months ago. What is a likely diagnosis?
Cushing’s disease (Pituitary Pars Intermedia Dysfunction).
The correct answer is Cushing’s disease. The coat condition described is what horses with glucocorticoid excess develop; it is referred to as hirsutism. They will also be predisposed to infections including laminitis and skin diseases such as Dermatophilus. They are also frequently polyuric, polydipsic, and polyphagic.
Once infected, for what period of time is canine parvovirus usually shed?
7-10 months.
The correct answer is 7-10 days. Canine parvovirus mainly affects puppies and young dogs less than a year of age. Transmission of the virus is through contact with infected feces and fomites such as hands, toys, the dog’s hair coat. The virus is very resilient in the environment and is resistant to many types of disinfectants. It replicates in the crypt epithelium of the gut and causes epithelial necrosis and hemorrhagic diarrhea. The virus can also affect the heart of young puppies, causing myocarditis. This occurs less commonly now since most bitches are immunized against the virus, which allows for maternal antibodies to protect young puppies from this form of the disease.
A 2-year old mare presents to you several weeks after recovering from a mild upper respiratory infection. She now presents with edema and sloughing of the legs (see image), chest and abdomen as well as mucosal petechial hemorrhages. She is sore and reluctant to move. Biopsy of the skin lesion is consistent with aseptic necrotizing vasculitis. What is the most likely diagnosis?
Type I hypersensitivity
Purpura hemorrhagica
Idiopathic thrombocytopenia
Bastard strangles
Cantharidin toxicity
This is the clinical and histologic appearance of purpura hemorrhagica. It is a type-Ill hypersensitivity which is when antigen-antibody complexes accumulate, leading to disease.
Purpura hemorrhagica most commonly occurs 2-4 weeks after exposure to certain infectious agents or vaccines. This condition is most commonly seen subsequent to infection with Streptococcus equi subsp. equi or vaccination against it but it can also be associated with other pathogens, particularly respiratory pathogens including other streptococcal species and equine influenza.
Regardless of the cause, purpura hemorrhagica results from accumulation of antigen-antibody complexes that deposit on blood vessel walls and activate a strong immune response (vasculitis). The leaky blood vessels lead to hemorrhage and edema.
Bastard strangles refers to the condition when Streptococcus equi subsp. equi creates abscesses in unusual sites (other than the lymph nodes draining the throat) such as abdominal or lung lymph nodes.
Cantharidin toxicity (also known as blister beetle toxicity) leads to mucosal irritation and results in colic and cystitis. It can also lead to hypocalcemia.
Primary immune-mediated thrombocytopenia (sometimes called idiopathic thrombocytopenia) can be seen in horses but is not consistent with the necrotizing vasculitis described in the case.
Type I hypersensitivity reactions are immediate reactions (such as urticaria) invoked by an antigen or allergen.
A 2-year old nonlactating dairy cow in California has a sudden onset of head tilt and drooling. The owner also reports that she appears less active and less interested in feed than normal, and today is circling in one direction in the pen. You examine her and find T=105F (40.6 C), HR=96, and RR=32. There is ptosis, drooped ear, and weakness of the lips on the affected side. You take a lumbosacral spinal tap (see photo), and submit the CSF to your lab. The results show elevated protein and WBCs, with the cell type being mainly monocytes. The lab reports seeing some gram positive bacteria in the monocytes of the CSF. Based on these findings what is the best treatment for this condition?
Metronidazole
Chloramphenicol
Enrofloxacin
Metoclopramide
Penicilin
Answer: Penicillin
The diagnosis is Listeriosis. Listeria monocytogenes can effectively be treated in the early stages of the disease with penicillin, ampicillin, or tetracycline. Intramuscular procaine penicillin for example has a withdrawal of 10 days for slaughter (meat) and 48 hours for milk if the animal is lactating. Other choices of approved antimicrobials would also likely be effective since L. monocytogenes is susceptible to most antimicrobials.
For a list of approved animal drugs see www.farad.org/vetgram.
FARAD is the United States Food Animal Residue Avoidance Databank which gives withdrawal information as well as a list of prohibited drugs. The other drugs listed as choices here are prohibited and cannot be legally used in food animals in the USA.
A 6-month old Chocolate Labrador presents for limping and failure to gain weight. He is housed in an outdoor kennel with other hunting dogs. He is fed a large breed dry puppy food. He received his puppy shots at 8, 12, and 16 weeks old. He is quiet, alert, and responsive. His body condition score is 3/9, with rib exposure and poor fat deposition. His mucous membranes are pale pink, with a capillary refill time of 2 seconds. His heart and lungs auscult normally. No abnormalities are felt on abdominal palpation. He is an intact male, and both testicles are descended. The only abnormalities are the pads of his two front feet and left hind foot (see image) that he chews at frequently. What is diagnostic test of choice?
Fecal float
Skin scraping
Biopsy
Radiographs
CBC and Chemistry panel
FCV and TP
Answer: Fecal float. 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.
A pregnant mare was brought out to your barn for observation in anticipation of parturition. After several hours of restless behavior, several gallons of allantoic fluid rush out from the vulva. Which of the following would you expect to happen next for a normal parturition?
The placenta is expelled from the vulva
The hind legs of the foal emerge from the vulva
The thin, white, glistening amniotic membrane emerges from the vulva
The red, velvety, chorioallantoic membrane emerges from the vulva
The thin, white, glistening amniotic membrane emerges from the vulva
This case description is consistent with stage I of labor in the horse. The first stage of foaling typically lasts 30 minutes to 4 hours. During this stage, mares act restless and may exhibit signs similar to colic such as flank watching, pawing, and constantly getting up and down. When the placenta ruptures (“water breaks”), there may be several gallons of allantoic fluid that come out. Usually, within about 5 minutes, the second stage of labor begins and the foals feet and nose appear at the vulva, covered in the white, thin, glistening amnion. If a red, velvety, membrane is seen, this is the chorioallantois which indicates premature placental separation which can impair oxygen delivery to the fetus and can result in death of the foal. Usually, the muzzle will emerge from the amnion by the time the foal’s hips pass through the pelvis but if not, the amnion can be gently broken and removed. Usually, the umbilical cord breaks naturally when the mare stands or foal begins to rise. Then, within 30 minutes to 3 hours after foaling, the placenta should be expelled.
A 2-year old male neutered cat presents to you depressed, hypersalivating, and ataxic with muscle tremors. The owner reports that a pyrethrin-based spot-on formulation for flea control belonging to their Golden Retriever was accidentally applied on the cat earlier today. Which of the following drugs will you use to treat the cat’s clinical signs?
Amoxicilin
Atropine
Methocarbamol
2-PAM
Acepromazine
Answer: Methocabamol. Pyrethrins alter the activity of the sodium ion channels of nerves, which prolongs the period of sodium conductance. This increases the length of depolarization resulting in repetitive nerve firing. Cats are particularly sensitive to pyrethrin-containing products and can develop clinical signs within hours after administration. Affected animals should be bathed to remove remaining product. Minor clinical signs such as hypersalivation and ear twitching are usually self-limiting and do not require treatment. Control of marked tremors or seizures can be achieved with methocarbamol (Robaxin).
What is the potential udder fate of goats infected with caprine arthritis encephalomyelitis virus?
The udder is not affected
Bluebag
Gangrene
Hardbag
Answer: herdbag. CAEV is a retrovirus and when it affects the udder it will cause fibrosis and result in a firm udder with agalactia. Treatment is ineffective and the goat should be culled. The disease is usually subclinical but can cause arthritis in adults and encephalitis in kids.
A 7-year old male castrated cat presents for respiratory distress with open-mouth breathing. You initially place him in oxygen and obtain thoracic radiographs when he is stabilized. The films are shown here. What is your diagnosis?
Tracheal collapse
Feline asthma syndrome
Pneumonia
Neoplasia
Left-sided congestive heart failure
Answer: Left-sided congestive heart failure.
The correct answer is left-sided congestive heart failure. The cardiac silhouette is tall suggestive of left ventricular enlargement, and there is an alveolar pattern in the lung fields. The pulmonary vasculature is also dilated. Remember that cats in heart failure can have edema distributed in patchy infiltrates throughout the lungs, in contrast to dogs where it is more typically in the perihilar region.
Asthma is less likely as no clear bronchial markings are seen and because of the infiltrate. Neoplasia is a consideration, but doesn’t explain the cardiac enlargement. Pneumonia could also cause this pattern of infiltrate (although it is more typically cranioventral), but also does not explain the cardiomegaly. There is no evidence of tracheal collapse, which is an exceedingly rare condition in the cat.
Annotations:
Orange: The cardiac silhouette is diffusely enlarged moderately
Yellow circle: Areas of alveolar pattern
Blue: pulmonary veins
Red: Pulmonary arteries. In this case there is enlargement of both the pulmonary arteries and veins
Green: pleural fissure line, most likely indicative of pleural effusion
What is the potential udder fate of goats infected with caprine arthritis encephalomyelitis virus?
The udder is not affected
Bluebag
Gangrene
Hardbag
Answer: hardbag. CAEV is a retrovirus and when it affects the udder it will cause fibrosis and result in a firm udder with agalactia. Treatment is ineffective and the goat should be culled. The disease is usually subclinical but can cause arthritis in adults and encephalitis in kids.
A 9-month old male pitfall presents to you for hindlimb lameness that developed suddenly several days ago and has gotten worse. On your examination, the dog is painful on palpation of the left tibia. Your take radiographs of the tibia which are shown below. Which of the following is the most appropriate treatment for the suspected condition?
Fluconazole
Ampicullin
Splint stabilization
Surgical correction
Carprofen
Answer: Carprofen.
This is a case of panosteitis based on the young age of the patient and radiographic presence of focal intramedullary densities within the tibial 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. Therefore, carprofen is the best answer choice listed. 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.
Annotations:
Circled: There are focal areas of increased patchy medullary sclerosis in the distal femur and proximal tibia.
The dog in the photograph was vaccinated earlier in the day. What type of allergic reaction is occurring?
Type I
Type II
Type IV
Type III
Answer: Type I.
The correct answer is type I. Type I hypersensitivity is IgE-mediated and results in immune mediated hypersensitivity. Type II hypersensitivity is an antibody-dependent reaction and occurs due to IgG or IgM made against normal self antigens or some foreign antigen that resembles some molecule on the surface of host cells. Type III hypersensitivity is an immune complex-mediated reaction. This is caused when soluble antigen-antibody complexes form in large amounts and overwhelm the body instead of being normally removed by macrophages in the spleen and liver. Type IV is considered a delayed hypersensitivity and is cell-mediated. T8-lymphocytes will be sensitized to an antigen and differentiate into cytotoxic T-lymphocytes. T helper 1 type T4-lymphocytes become sensitized to an antigen and produce cytokines.
A 3-year old female spayed indoor/outdoor domestic short hair presents for congestion and swelling over the bridge of the nose. The swelling over the nose is firm and seems to be subcutaneous. There is also mild enlargement of the mandibular lymph nodes. You perform cytology from a fine needle aspirate of the swelling over the nose and see narrow, budding, thick-walled yeasts surrounded by clear capsules (see picture). You also detected a lesion in the retina on fundic examination. Which of the following treatments would be indicated?
Doxycycline
Itraconazole
Trimethroprim sulfa
Amoxicillin-clavulanic acid
Lufenuron
Answer: Itraconazole.
Based on the description of the cytology and clinical symptoms of this cat, the most likely diagnosis is Cryptococcus neoformans. This is a fungal disease that occurs when the organism is inhaled and is disseminated to skin, eyes, CNS, lungs, or other areas. The upper respiratory tract is most often involved and symptoms can include nasal discharge, sneezing, swelling over the nose, and regional lymphadenopathy. If the CNS is involved, seizures can also occur. The disease has been thought to be transmitted most often through infected pigeon droppings. Itraconazole, fluconazole, or amphotericin B are the anti-fungals of choice for this disease. Doxycycline, Trimethoprim sulfa, and Clavamox are all antibiotics and would not address a fungal infection. Lufenuron is a flea treatment that has had some implications for treatment of dermatophytes due to its ability to inhibit chitin. About 1/3 of the cell wall of a fungus is composed of chitin. This has not been a promising or approved treatment for ringworm and surely would not be an appropriate treatment for Cryptococcus.
A dog presents to your clinic with tenesmus and swelling near the anus as seen in the image. On examination, there is a fluctuant swelling lateral to the anus, and on rectal exam, you note lateral dilatation of the rectum. Which of the following is the most common signalment for dogs presenting with this problem?
They are younger intact females
There is no age sex predilection
They are older intact males
They are older intact females
They are younger intact males
They are older intact males.
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.
A 9-year old male Queensland Heeler presents with a four day history of progressive tetraparesis. Physical exam showed him to be weakly ambulatory with support. As part of your initial workup, you take chest X-rays which are shown below. Which of the following next steps is the most appropriate test to confirm your clinical suspicion about the cause of the dog’s signs?
- Bronchoalveolar lavage and culture
- CT scan of the thorax
- MRI of the brain
- Tensilon response test
- Myelogram
Answer: Tensilon response test
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.
Annotations:
Red arrow: the trachea is displaced dorsally due to the cranial mediastinal mass
Green circle: on the right lateral projection there is increased soft tissues in the ventral aspect of the thorax. The ventral aspect of the cardiac silhouette remains partially visible.
On the left lateral projection, there is also increased soft tissue opacity in the ventral aspect of the thorax. However on that projection the cardiac silhouette is not clearly visualized (purple circle). On both projections there is mild separation of the lung lobes indicating the concurrent pleural effusion (blue line)
On the VD the mass is highlighted in orange, the cardiac silhouette in pink. The cranial aspect of the cardiac silhouette is not clearly visualized due to “silhouetting”.
Radiographs provided by Adrien Hespel, DVM, MS, DACVR and University of Tennessee College of Veterinary Medicine
Link:
https://www.vetprep.com/simboards/qod/dailydose-answer.jsp?userId=jQjubBVWYJXhT4059263&questionId=AsbpykmrLhFauUp69206&answerOrder=41203&historyId=256474221&answerId=FmhviKTCYWLiwFB69208&
A 10-day old commercial dairy calf has diarrhea that is white in color (see photo). The calf is dehydrated, hypovolemic, weak and unable to stand. T=100F (37.8 C), HR=100, and RR=20. No other abnormalities are found on physical examination. Based on these findings, what is the treatment of choice?
IV fluids containing 50mEq/L of potassium
Oral fluids containing sodium bicarbonate
Oral fluids containing high levels of both sodium and chloride
IV fluids containing only saline
IV fluids with added sodium bicarbonate
This calf is typical of those suffering from nonspecific calf diarrhea, most often associated with enteropathogenic E coli, rotavirus, or cryptosporidium. The calf develops hypovolemia and metabolic acidosis and requires sodium-containing IV fluids which contain additional alkali such as sodium bicarbonate. One can assess that the calf is severely acidotic given that it is lethargic and unable to stand. While oral fluids may also be useful, at this stage, the calf will require IV fluids.
A male goat presents for vocalizing and straining to urinate. He has been kicking at his abdomen. You detect crystals adherent to the hairs around the prepuce (see image). What condition should you suspect and try to rule out first?
Lower intestinal obstruction
Urinary tract obstruction
Acute severe pyelonephritis
Upper intestinal obstruction
Answer: Urinary tract obstruction.
The correct answer is urinary tract obstruction due to calculi. This should be suspected in all male and castrated male goats (and sheep) with non-specific signs of disease or discomfort because it is so common. Common clinical signs associated with urinary tract obstruction are vocalization and dribbling of urine. Heaving or forceful abdominal contractions may be seen. Hematuria, dysuria, prolonged urination, and apparent abdominal pain are also common signs. The most important step of evaluation is exteriorization of the penis and examination of the urethral process because this is the most common site of blockage. In severe cases the entire urethra may be filled with calculi.
Rubiosis iridis as seen in this cat is a sign of what process in the eye?
Chorioretinitis
Anterior uveitis
Glaucoma
Iris atrophy
Lens luxation
Answer: Anterior uveitis
The correct answer is anterior uveitis. Rubiosis iridis along with other signs such as aqueous flare, hyphema, hypopyon, keratic precipitates, and decreased intraocular pressure are all suggestive of anterior uveitis which can be caused by a number of infectious, immune-mediated, traumatic, and idiopathic causes.
During your examination of an 18-year old horse, you observe what is shown in the photograph. Based on the location and appearance of this lesion, what is the most likely diagnosis?
Melanoma
Sarcoid
Habronema
Cuterebra
Squamous cell carcinoma
Answer: Melanoma.
The correct answer is melanoma. Melanoma is one of the most common tumors in horses (about 10% of all neoplasms) and gray horses are at high risk of around 80%. They can occur anywhere but appear most frequently in the perineal region or ventral tail as is evident in this horse.
In horses, they are usually darkly pigmented (as opposed to dogs where amelanotic melanomas occur somewhat commonly). In horses, most are slowly growing but can be locally invasive. Many treatments are out there, but there is no standard of care treatment. Depending on location and extent, consider surgical removal, benign neglect, chemotherapy (systemic or intralesional) and immunotherapy.
A 7-year old female Lhasa Apso presents to you for lethargy and inappetence. On your exam, you detect mandibular lymphadenopathy and perform a fine needle aspirate. You see the aspirate depicted here. Which of these treatments would be given to this patient as part of a first line therapy?
Carboplatin
Itraconazole
Prednisone
Doxycycline
Milbemycin
Answer: 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).
A horse presents to you with a corneal ulcer. You are concerned because it appears to be infected, as shown in this image. You perform cytology and find gram negative rods. What is the most likely organism infecting the corneal ulcer in this horse?
- E. Coli
- Pseudomonas
- Pasteurella multocida
- Staphylosoccus spp.
Answer: Pseudomonas.
The correct answer is Pseudomonas
Pseudomonas is the most common agent causing bacterial keratitis in the horse. The gram negative cytology provides further evidence that it is the likely culprit. Staphylococcus can cause keratitis in horses but is gram positive. E. coli and Pasteurella are not agents that are commonly involved with keratitis in the horse.
A 6-year old male neutered Weimaraner presents for right forelimb lameness. Radiographs are shown below and show a mixed productive and destructive lesion affecting the right distal radius with accompanying soft tissue swelling. The lesion does not cross the joint. What is the most common primary bone tumor in the dog?
Chondrosarcoma
Osteosarcoma
Hemangiosarcoma
Fibrosarcoma
Multiple myeloma
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The correct answer is osteosarcoma. Chondrosarcoma, fibrosarcoma and hemangiosarcoma can all be primary bone tumors but are much less common in dogs than osteosarcoma.
Annotations:
Yellow: Amorphous periosteal proliferation
Orange: Geographic lysis and expansile appearance of the mid-radius
Blue: soft tissue swelling
Radiographs provided by Adrien Hespel, DVM, MS, DACVR and University of Tennessee College of Veterinary Medicine
The image below shows pemphigus foliaceus on a dog’s abdomen. Pemphigus foliaceus, pemphigus vulgaris, and bullous pemphigoid are examples of which type of immune-mediated disease?
Type II. Antibody binds cell antigen and activates complement.
Pemphigus foliaceus, pemphigus vulgaris, and bullous pemphigoid are generally considered type II reactions. Antibody binds antigen on a cell, then the antibody-antigen complex activates complement, causing cell lysis. In general, think of rare, autoimmune skin diseases characterized by varying presentations of ulceration, crusting, pustules, vesicles.
FYI: “Delayed hypersensitivity” is the same as a type IV reaction.
A 1-year old mixed breed stray dog is presented for extreme pruritis and the lesion shown in the picture. The dog was recently found and adopted off the street and has been itching despite being bathed and treated with flea preventatives. The owner reports that she has been itching and developing rashes on her own body since adopting this dog. Your physical exam shows that the dog has several additional similar lesions on the other legs, chest, and ventral abdomen. What is the most likely diagnosis?
Cutaneous lymphoma
Sarcoptes infestation
Demodex infection
Squamous cell carcinoma
Answer: Sarcoptes infestation.
The key to this question is that Sarcoptic mange is extremely pruritic and can be transmitted to people, including this dog’s owner. Diagnosis of this disease is usually based on clinical impression and potential for exposure to the mites. A positive skin scraping would be most definitive, but scrapes often come back negative and trial therapy would need to be instituted.
Demodex is not transmittable to people and does not typically cause extreme pruritus like Sarcoptes.
Lymphoma and squamous cell carcinoma are less likely because they typically would occur in older animals and neither are usually particularly itchy.
A 11-year old male castrated Golden Retriever presents for collapse with muffled heart sounds on examination. You ultrasound the heart and obtain the following image; the right atrium (RA) and right ventricle (RV) are labeled. A large mass is seen in the right atrioventricular groove with pericardial effusion. What is the likely diagnosis?
Idiopathic pericardial hemorrhage
Hemangiosarcoma
Chemodectoma
Pulmonary adenocarcinoma
Lymphoma
Answer: Hemangiosarcoma.
The correct answer is hemangiosarcoma. Hemangiosarcoma of the heart has a predilection for the right auricle of dogs, with Golden Retrievers being predisposed. Stabilization of this patient will require pericardiocentesis; prognosis is guarded and may include chemotherapy, pericardiectomy, or rarely auriculectomy. Chemodectoma arises from the ascending aorta and heart base; lymphoma is rare in the heart of dogs and is more commonly metastatic than a single mass. Idiopathic pericardial hemorrhage is incorrect because of the clear evidence of a mass.
An 11-year old female Pomeranian presents to you for coughing and exercise intolerance. On exam: Wt: 9.25 lbs, T: 101.2F (38.4 C), HR: 132 bpm, RR: Panting, mucous membranes are pink. She has mild tracheal sensitivity and a grade III-IV/VI left apical holosystolic murmur and grade II/VI right apical holosystolic murmur. Femoral pulses are strong and synchronous, with a regular rhythm. She has harsh lung sounds bilaterally. On abdominal palpation, you note hepatomegaly. You find bilateral luxating patellas. You take chest radiographs (see image) and decide to treat the dog based on these findings. Which medication plan is most appropriate?
Answer: Furosemide and Enalpril.
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 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.
Annotations:
There is marked elongation of the cardiac silhouette on the lateral views (yellow line) resulting in dorsal displacement of the trachea (red area), consistent with left ventricular enlargement.
A large focal bulge is noted at the caudodorsal aspect of the cardiac silhouette consistent with left atrial enlargement. (Purple circle)
A focal soft tissue opaque bulge is also noted in the region of the left auricle on the DV view. (Pink circle)
There is concurrent mild widening of the cardiac silhouette on the lateral views consistent with right-sided cardiomegaly (orange line).
The cranial lobar pulmonary veins are larger than the corresponding arteries. There is mild distension of the caudal lobar pulmonary arteries and veins with right caudal lobar pulmonary vein slightly larger than the corresponding artery. (green lines)
There is a marked diffuse unstructured interstitial pattern to early alveolar pattern (blue circle), most severe in the dorsal aspects of the right caudal and left caudal lung lobes.
The liver is mildly enlarged, extending beyond the costal arch with rounded caudoventral margins. (brown circle)
Radiographs provided by Adrien Hespel, DVM, MS, DACVR and University of Tennessee College of Veterinary
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Some farmed salmon appear lethargic with darkened skin and exophthalmia. Necropsy of one that died reveals vent hemorrhages and grayish granulomatous nodules on the kidneys. Gram stain from the kidney lesion reveals the intracellular bacteria shown below. What is the best option to prevent this condition?
Answer: Screen broodstock with qPCR and cull positives
Renibacterium salmoninarum (bacterial kidney disease, BKD) is best prevented by screening broodstock with qPCR and culling any positives to prevent vertical transmission. Another option is to use ELISA to screen the broodstock and cull the eggs from positives.
R. salmoninarum is one of the relatively few gram-positive organisms that causes disease in fish and it is economically important.
Fish appear lethargic with darkened skin and sometimes exophthalmia. There may be grayish granulomatous nodules on the kidneys. It is transmitted both horizontally and vertically and disease is more common in younger fish.
Bacterial kidney disease is most common in both farmed and wild salmonids, but also occurs in other fish species. Purchase BKD/Renibacterium-free stock to avoid introducing this into the system.
Previously it was recommended to treat females with erythromycin before spawning. However, this is not FDA-approved for treatment in farmed salmonids (there is an INAD available but not best use of antimicrobials and is difficult to get the drug) and survivors remain carriers.
A horse presents to you with a corneal ulcer. You are concerned because it appears to be infected, as shown in this image. You perform cytology and find gram negative rods. What is the most likely organism infecting the corneal ulcer in this horse?
Answer: Pseudomonas.
The correct answer is Pseudomonas. Pseudomonas is the most common agent causing bacterial keratitis in the horse. The gram negative cytology provides further evidence that it is the likely culprit. Staphylococcus can cause keratitis in horses but is gram positive. E. coli and Pasteurella are not agents that are commonly involved with keratitis in the horse.
A 7-month old feedlot steer has died after exhibiting severe fever, dyspnea, cough and respiratory distress. On post mortem there is evidence of fibrinopurulent bronchopneumonia (see image). What bacterium is most likely to be the cause of this syndrome?
Mannheimia hemolytica
This is recognized as the worst pathogen in bovine pulmonary disease. It was formerly called Pasteurella hemolytica.
A 2-year old mare presents to you several weeks after recovering from a mild upper respiratory infection. She now presents with edema and sloughing of the legs (see image), chest and abdomen as well as mucosal petechial hemorrhages. She is sore and reluctant to move. Biopsy of the skin lesion is consistent with aseptic necrotizing vasculitis. What is the most likely diagnosis?
Type I hypersensitivity
Purpura hemorrhagica
Idiopathic thrombocytopenia
Bastard strangles
Cantharidin toxicity
Answer: Purpura hemorrhagica
This is the clinical and histologic appearance of purpura hemorrhagica. It is a type-Ill hypersensitivity which is when antigen-antibody complexes accumulate, leading to disease.
Purpura hemorrhagica most commonly occurs 2-4 weeks after exposure to certain infectious agents or vaccines. This condition is most commonly seen subsequent to infection with Streptococcus equi subsp. equi or vaccination against it but it can also be associated with other pathogens, particularly respiratory pathogens including other streptococcal species and equine influenza.
Regardless of the cause, purpura hemorrhagica results from accumulation of antigen-antibody complexes that deposit on blood vessel walls and activate a strong immune response (vasculitis). The leaky blood vessels lead to hemorrhage and edema.
Bastard strangles refers to the condition when Streptococcus equi subsp. equi creates abscesses in unusual sites (other than the lymph nodes draining the throat) such as abdominal or lung lymph nodes.
Cantharidin toxicity (also known as blister beetle toxicity) leads to mucosal irritation and results in colic and cystitis. It can also lead to hypocalcemia.
Primary immune-mediated thrombocytopenia (sometimes called idiopathic thrombocytopenia) can be seen in horses but is not consistent with the necrotizing vasculitis described in the case.
Type I hypersensitivity reactions are immediate reactions (such as urticaria) invoked by an antigen or allergen.
Purpura Hemorrhagica in Animals - Comprehensive Information
Definitions and Causative Agents:
• Purpura Hemorrhagica: Immune-mediated vasculitis characterized by hemorrhage and edema. • Causes: Often secondary to infections such as Streptococcus equi (strangles).
Clinical Changes and Symptoms:
• Symptoms: Edema (head, limbs), petechial hemorrhages, fever, mucosal ulcers. • Pathogenesis: Immune complex deposition in blood vessel walls leading to vasculitis and increased vascular permeability.
Diagnosis:
• Tests: History, clinical signs, CBC, biopsy. • Findings: Leukocytosis, thrombocytopenia, immune complexes in vessel walls.
Treatment:
• Medications: • Corticosteroids: Prednisone (1-2 mg/kg/day). • Antibiotics: For underlying infection. • Supportive Care: Fluids, anti-inflammatory drugs.
A ten-year-old female spayed Persian cat is presented for evaluation of a two-month history of a mass. There is a two-cm diameter, firm, solitary, hairless, dome-shaped, ulcerated mass on her left neck just behind the jaw that is bleeding.
Cytology obtained by fine needle aspirate reveals cohesive clusters of large cells with round to oval nuclei that are tightly adherent to each other (see below).
What is the most appropriate treatment option?
A - Surgical removal
B - Cryosurgery, debridement, repeat in 3 - 5 weeks
C - Debulk, intralesional implant chemotherapy, minimize sun and cigarette smoke exposure
D- Immunotherapy, wide margin excision, chemotherapy
E - Wide excision of mass, remove regional lymph node, prednisolone, radiotherapy
Answer: Surgical removal
This is a basal cell tumor. Basal cells make up the base of the epidermis, and a benign growth of these is called a basal cell tumor or adenoma. Although this tumor is benign, surgical removal is the treatment of choice due to ulceration and secondary inflammation. Basal cell carcinomas (the malignant form) do not form raised masses but
appear as ulcers on the head, neck, and legs: surgical removal is also recommended.
Basal cell tumors are common in older cats, accounting for 15-26% of all feline skin tumors. Most are slow growing and typically present for months prior to diagnosis.
Domestic longhairs, Himalayans, and Persians are predisposed.
Note the characteristic cytology findings of epithelial neoplasia present in this case: cohesive clusters of large, round to polygonal cells, demonstrating distinctive cell borders, that are tightly adherent to each other with round to oval nuclei.
https://www.merckvetmanual.com/cat-owners/skin-disorders-of-cats/tumors-of-the-skin-in-cats#v3247101
https://eclinpath.com/cytology/cytology-interpretation/
A ten-year-old female spayed Persian cat is presented for evaluation of a two-month history of a mass. There is a two-cm diameter, firm, solitary, hairless, dome-shaped, ulcerated mass on her left neck just behind the jaw that is bleeding.
Cytology obtained by fine needle aspirate reveals cohesive clusters of large cells with round to oval nuclei that are tightly adherent to each other (see below).
What is the most appropriate treatment option?
A - Surgical removal
B - Cryosurgery, debridement, repeat in 3 - 5 weeks
C - Debulk, intralesional implant chemotherapy, minimize sun and cigarette smoke exposure
D- Immunotherapy, wide margin excision, chemotherapy
E - Wide excision of mass, remove regional lymph node, prednisolone, radiotherapy
Answer: Surgical removal
This is a basal cell tumor. Basal cells make up the base of the epidermis, and a benign growth of these is called a basal cell tumor or adenoma. Although this tumor is benign, surgical removal is the treatment of choice due to ulceration and secondary inflammation. Basal cell carcinomas (the malignant form) do not form raised masses but
appear as ulcers on the head, neck, and legs: surgical removal is also recommended.
Basal cell tumors are common in older cats, accounting for 15-26% of all feline skin tumors. Most are slow growing and typically present for months prior to diagnosis.
Domestic longhairs, Himalayans, and Persians are predisposed.
Note the characteristic cytology findings of epithelial neoplasia present in this case: cohesive clusters of large, round to polygonal cells, demonstrating distinctive cell borders, that are tightly adherent to each other with round to oval nuclei.
https://www.merckvetmanual.com/cat-owners/skin-disorders-of-cats/tumors-of-the-skin-in-cats#v3247101
https://eclinpath.com/cytology/cytology-interpretation/
