ICVA NAVLE Exam Questions

Correct answer: Leptospirosis; Intrinisic renal disease

The dog in this example is classic for leptospirosis. He has an acute kidney injury (AKI) due to intrinsic renal disease. Intrinsic disease can manifest as either glomerulonephritis or interstitial nephritis.

AKI can occur for three main reasons:

1. Decreased renal perfusion secondary to prerenal etiologies, such as dehydration, hypotension, or low circulating blood volume, as can be seen with chronic liver disease or heart disease. This patient has no notes suggesting any primary heart disease, and elevated liver values in chronic liver disease often include additional values, such as AST or GGT. They may have changes in glucose levels or other parameters. Further, the change in urination and metabolic acidosis suggests that, while there may be a degree of dehydration and prerenal component, the primary concern is kidney damage, an intrinsic renal disease.
2. Intrinsic renal disease would be secondary to inflammation (nephritis) or tubular necrosis (nephrosis). We see nephrosis as a consequence of toxic injury, ischemic damage, or trauma. For example, toxins such as ethylene glycol or aminoglycosides can lead to nephrosis. On the other hand, nephritis is either glomerular or interstitial in nature. Commonly recognized causes include leptospirosis, Rocky Mountain spotted fever, ehrlichiosis, bacteremia/septicemia, and Lyme disease.
3. For post-renal causes think of the blocked cat or dog with a urethral stone that cannot urinate. Animals hit-by-cars with bladder ruptures would also fall into this category.

Chronic renal disease factors include a decreasing renal reserve with insufficiency leading to complete loss of kidney function (IRIS stage 4 chronic kidney disease [CKD]).

Leptospirosis is a zoonotic, global spirochete infection of mammals. General clinical signs in animals include fever, not wanting to move, anorexia, pu/pd, d/v, lethargy, abdominal pain, +/- icterus, or respiratory challenges. Key differential diagnoses include nephrotoxicosis (NSAID toxicity), Lyme, acute glomerular disease, cholangiohepatitis, pyelonephritis, canine monocytic ehrlichiosis, sepsis, leishmaniasis, or Rocky Mountain spotted fever.

Humans with leptospirosis develop mild flu-like illnesses all the way to life-threatening multisystemic diseases. Dogs are accidental hosts to Leptospira species. Organisms are shed in the urine, and transmission occurs through contact with the urine of infected animals. Several serovars have been associated with the disease, and vaccinations vary depending on what serovars are covered. Though increased disease occurrences may manifest in the rainy seasons or after floods, we are increasingly seeing this not just in rural areas, but also in cities.

Initially, dogs may demonstrate a high fever, which is often transient, with shivering and moderate muscle aches, +/- uveitis. Additionally, dogs may develop pulmonary hemorrhage and lung involvement. At the same time, others may have significant liver disease to the point of liver failure. Dogs with lepto may have increased bleeding tendencies resulting in hematuria, hematemesis, epistaxis, petechiae, or melena, though uncommon in the U.S. Any dog with elevated kidney values +/- liver values should be evaluated for Lepto.

Diagnostics for this pet should include CBC, chemistry, coagulation tests, and urinalysis (can have varied urine concentrations and variable proteinuria, bilirubinuria, and glucosuria). Radiographs may show pulmonary changes if lepto is invading the respiratory tract. Otherwise, rads may be non-remarkable. Ultrasound can show renomegaly, cortical thickening, pyelectasia (mild), increased renal cortical echogenicity (bright kidneys), a medullary band within the kidneys, and may have some perirenal fluid accumulation.

The testing culture is not generally effective because the organism is very slow-growing and insensitive. Serological diagnostics have significant limitations. Currently, the MAT (Microagglutination Test) is the primary means of detection. Several bedside urine tests using ELISA are now available. The Witness Lepto test can differentiate between wild strain and vaccine strain, while the SNAP lepto test cannot.

Treatment is with antimicrobials, fluid therapy, and supportive care. A urinary catheter should be placed to permit proper measurement of urine ins and outs and minimize the risk of contamination and exposure to staff). Proper protective equipment, including gloves, eye protection, and disposable gowns, should be worn when handling the patient. Handwashing pre- and post-handling is paramount. Those who are pregnant or immunosuppressed should not care for the patient. Regularly disinfect all areas that come in contact with urine. Proper isolation and/or signs noting the zoonotic contagious risk of the patient to others.

Correct answer: We do not have a duty to report other veterinarians who do not practice competently or who fail to behave and practice to the letter of the law

The AVMA has a long list of principles that govern veterinary medical ethics. According to the AMVA, we are "expected to adhere to a progressive ethical conduct known as the Principles of Veterinary Medical Ethics (PVME)." The PVME includes useful terms, supporting annotations, and specific principles.

Included in those principles:

1. A vet should ensure professionalism, practice honesty, and "report veterinarians who are deficient in character or competence to the appropriate entities."
2. A vet must respect the rights of all individuals, including clients, other health professionals, and colleagues.
3. Veterinarians are expected to pursue continuing education and ensure we are up-to-date on the latest scientific knowledge and that others, including the public, colleagues, and clients, have access to the information we glean. This includes obtaining consultation from others or referral to a specialist when indicated. (Sadly, referral happens much less often than it should, either because vets fail to recognize their shortcomings, do not want their patients to go elsewhere, or for unknown reasons.) 
4. We can decline to serve a client or patient based on various reasons, except in the case of emergencies. We can also choose where we practice veterinary medicine.

For the full list of the PVME, please visit the AVMA website.

Correct answer: Curative; non-malignant trichbolastoma

The most common skin tumor in cats (15–26% of feline skin tumors) are histologically noted to be trichoblastomas. These are considered basal cell tumors, and less than 10% are malignant in cats, so surgery should be curative for this patient.

Malignant basal cell tumors in cats are uncommon but have a tendency towards lymphatic metastasis if present. Thus, follow-up with an oncologist may be warranted. Lymph node aspiration or biopsy may also be considered.

Dogs commonly get sebaceous adenomas, which, while benign, do not usually occur in cats.

Apocrine gland carcinomas (arising from sweat glands) are rarely malignant but can become aggressive if transformed into a carcinoma. Malignant lesions are usually found on cats' heads, while benign lesions may be on older felines' bellies, limbs, or heads.

Correct answer: Plasma cell pododermatitis

This is a classic presentation for plasma cell pododermatitis. Etiology isn't elucidated. Lesions in some individuals spontaneously regress (though not usually once a secondary infection has developed). Initially, animals will have foot pad swellings, which can be white with cracks. Swelling is soft and initially not painful until they become ulcerative. The lesions can be purple, as can the foot pad in general. In more advanced cases, regional lymphadenopathy may occur. Cytology may show significant numbers of plasma cells but doesn't fully confirm the diagnosis. Biopsy, as described above, does. Treatment is case-based as we do not have evidence-based medicine to address this condition. Initial therapy is recommended to start with doxycycline at 5–10 mg/kg q 12–24 for 30 days past resolution, then wean to the lowest effective dose +/- steroids at 4.4 mg/kg/day for a month after the resolution, then decreasing to the lowest effective dose. Some animals require lifelong therapy to prevent a recurrence. If severe ulceration occurs, animals may require surgical debridement to help improve wound healing.

If the above doesn't work, suggested next steps include chrysotherapy or chlorambucil. Most cases with doxy respond in two to three weeks, but it can take up to three months to see full improvement. Recurrence is possible, even for those that regress on their own.

Other possible differentials include cancer, infectious granulomas, or eosinophilic granuloma complex. However, cytology and biopsy help differentiate these entities.

Correct answer: Animals with wounds of unknown origin

Numerous factors can increase the risk of exposure to infectious diseases for any employee, regardless of pregnancy or immune status. These include handling tissue/blood and related samples for laboratory processing, performing necropsies, and contact with wildlife, exotic animals (including non-native species), and reptiles and amphibians (salmonella risks). Further, unvaccinated animals, those that are feral or stray, those recently exposed to an animal shelter situation, those with parasites (internal and external), the very young, those that are delivering young, and those fed raw food diets.

Animals with wounds of known origin (such as a bite wound) may be of concern if the animal was unvaccinated or if there is saliva all over the animal from a wild animal, and if rabies is of concern. However, using appropriate protective equipment and practicing safe handling practices shouldn't make this patient much different than any other, though precaution is still warranted. A wound of unknown origin would definitely need to be considered a higher risk for those immunocompromised/pregnant because the risk of rabies, tetanus, or other infectious etiologies could be higher.

There are no disease states that would exclude a person from working in a veterinary hospital, and health status cannot be used to deny work. However, it is reasonable to limit a person with a higher risk exposure to conditions, such as above, whenever feasible, or at minimum, ensure that personal protective equipment is available and its use is insisted upon.

Correct answer: Septic arthritis of the carpus

Acute lameness in a foal is a true pediatric emergency. While owners often assume the mare stepped on the animal, this tends to be uncommon. The number one cause of acute neonatal lameness in foals is osteomyelitis/septic arthritis. Differentials include physeal fractures, foot abscesses, muscle/tendon injuries, or long bone fractures. Additional causes of acute lameness in the foal may include hemarthrosis, cellulitis, flexural deformity, ruptured tendon, subsolar/solar bruising, peripheral nerve injury, or laminitis.  

Perform a thorough physical examination. If joint effusion is present, presume it to be septic, though remember palpation of effusion can be difficult in the shoulder, hips, and elbows and could be missed on physical exam. Obtain radiographs to determine changes and evaluate for fractures and other abnormalities. Diagnosis of septic arthritis requires radiographs, arthrocentesis, and cultures.

Arthrocentesis:

1. Normal values: TP < 2.0 g/dL; WBCs < 1000 cells/mL; neutrophils < 40%
   2. Septic arthritis: TP > 3 g/dL; WBCs >20,000 cells/mL; neutrophil counts > 80% +/- degenerative changes
   3. Septic physitis, while outside the joint, can still lead to a sympathetic joint effusion which will have mild to moderate TP increases, variable WBCs, and percent of neutrophils

Ensure effusion is cultured and perform a gram stain. 50% of cultures are negative. But this doesn’t mean that the joint isn’t septic. 25% of negative cultures will be positive on gram stain. Given the history, obtaining a culture from the umbilical area may also be beneficial in this foal.

Foals can be predisposed to septic arthritis secondary to a failure of passive transfer, prematurity/dysmaturity, poor foaling hygiene, placentitis in the mare, retained fetal membranes, dystocia, or any condition causing septicemia/bacteremia.

Signs of septic arthritis may be simply an acute severe lameness +/- weight bearing +/- more than one joint affected. The joint may be painful, swollen, and or hot to the touch. There may be pitting edema and peri-articular swelling. Painful animals may have elevated heart and respiratory rates. They may or may not have a fever. Some may have increased periods of recumbency and decreased nursing frequencies.

Treatment of septic arthritis includes broadspectrum antibiotics, local drainage and lavage of the joint(s) affected, and local antimicrobial therapy. Adjunctive therapy includes pain management and anti-inflammatory medications. Prognosis is guarded and worse if there is a concurrent systemic illness; multiple joints are affected; osteomyelitis is present, especially if it affects the weight-bearing surface; and if Salmonella species are cultured. 

Correct answer: Identify diseases in the mid-nasal area

Cats with feline herpes or caliciviruses are at risk for developing chronic upper respiratory disease, including chronic rhinitis and sinusitis.

Rhinoscopy is very helpful for a number of reasons, including:

• ID and remove a nasal foreign body
• Biopsy/cytology of mass lesions/mucosa
• ID source of epistaxis or chronic nasal discharge
• Investigate possible causes of nasopharyngeal disease and acute/upper respiratory tract signs, as in this patient
• Permits mucosal nasopharyngeal evaluation and biopsy samples of the nasopharynx but not deeper tissues or sinus evaluation

However, while non-invasive to a degree, if there are any underlying bleeding disorders, it is contraindicated due to the high vascularity of the nasal cavity. Further, if sinusitis is also suspected, not just chronic rhinitis, a CT is likely warranted in addition to the rhinoscopy to classify/determine the extent of damage to the nasal turbinates and the accompanying sinuses. Often, the CT is performed during the same anesthetic event as the rhinoscopy. Finally, if the nasal discharge is mucopurulent and extremely thick, this may limit visibility and prohibit complete examination via rhinoscopy.

Disadvantages include missing mid-nasal area disease, the high cost of the equipment, and failure to detect any pathology underneath and deep into the mucosa.

In conjunction with rhinoscopy and nasal biopsies/cytology, CT is most likely to glean the best information and help identify if the recurrent nasal discharge is from a chronic viral infection or another underlying cause.

Correct answer: Rabies

Rabies’ clinical signs, you explain to the producers, may include increased salivation, tremors, vocalization, aggression or detachment from the herd, hyperesthesia, and/or hyperexcitability. Some are photophobic and hydrophobic. Some may develop severe self-mutilation due to pruritus. They can develop rumen bloat, pharyngeal paralysis, ear droop, and limb paralysis and have varying behavioral changes. The onset of signs can be a few days after exposure to over six months or longer, depending on the location of the bite. Regardless of treatment, the disease will progress, eventually to cardiopulmonary failure in two to ten days.

The producer did the right thing in isolating the cow but needs to contact the proper authorities and the farm’s veterinarian to alert them of the possible rabies suspect. Further, re-evaluating their rabies vaccination program and protocols on the farm is warranted. The public health recommendations on what would need to be done with the other animals exposed to this single cow in the herd will vary — some may have them quarantined and monitored, while others may require immediate culling. However, the owner is adamant that the animal was fully vaccinated and asks if it could be something else. It is just a coincidence that a head wound occurred a month ago. Of course, this is possible, and some differentials need to be considered, including:

• Botulism causes a generalized initial muscle weakness followed by a progressive flaccid paralysis — animals will eventually be completely recumbent, and it can occur in a single animal or a herd.
  •   Toxin ingestion various ingestions can lead to neurological signs.
  •   BSE (Bovine Spongiform Encephalopathy) - A prion disease with a long incubation that can manifest in the GI tract, retina, and CNS and cause a variety of behavioral changes, weight loss, a decline in milk production, trouble getting up, ataxia and incoordination. 
  •   Listeriosis (most commonly manifesting as meningoencephalitis, though it can cause abortions/stillbirths, septicemia, and other changes in neonates and young animals, including uveitis and keratoconjunctivitis). CNS signs may include ear drooping, walking in circles, depression, tongue failing to retract into the mouth, increased nasal discharge, ptyalism, and head pressing. 
  •   Polioencephalomalacia can arise due to thiamine deficiency, sulfur toxicity, salt toxicity (water deprivation), or lead poisoning. 
  •   Hepatic encephalopathy (Signs of liver failure with toxic ammonia build-up, like head pressing)

However, hypersalivation, photophobia, and hydrophobia, with the additional neurological signs and the history of a wound, are highly suggestive of rabies. Because rabies is a highly fatal, zoonotic disease, it is rabies until proven otherwise. You explain that the cow must be euthanized and tested for rabies since there are no approved premortem diagnostics. Additional tests may be warranted to identify an underlying cause and ensure it isn’t contagious to other animals if the test is negative. However, if positive, that has ramifications for the whole herd and staff.

You emphasize that this disease is universally fatal in humans and animals. Though in humans, post-exposure prophylaxis has been shown +/- immunoglobulin therapy, in animals, pre-exposure vaccination and control of animal reservoirs in the habitat are key to prevention in livestock. You recommend that if this cow is rabid, the producer have the veterinarian review all records and re-evaluate the vaccination protocol and products used. 

Correct answer: Malnutrition

Noninfectious causes of abortion in ruminants may include:

1. Heat stress (more common in sheep and cattle than in other species) 
2. Other stress
3. Drug-induced causes, such as corticosteroid use 
4. Physical stress or confirmational issues
5. Malnutrition, though this is considered extremely rare and thus the least likely cause of abortion 
6. Nitrate toxicity

Numerous plants and water sources can acquire harmful levels of nitrates, including crops, forages, and weeds. Accumulation may occur because of drought, hail, frost, or herbicide use. Also, excessive cloudiness, damp weather conditions, cool temperatures, and shade impair photosynthesis and can lead to nitrate accumulation. Signs of toxicity in ruminants can include sudden death, birth defects, and abortion because nitrates readily cross the placental barrier. While cattle are the most commonly affected ruminant, other ruminants are also very susceptible because the flora in the rumen changes nitrates to ammonia. The intermediate byproduct of this conversion is nitrite, which is ten times more potent than nitrate.

Correct answer: Dexmedetomidine 7 µg/kg IM

Cats who ingest calcium channel blockers are at risk of developing bradycardia, hypotension, heart block, non-cardiogenic pulmonary edema, or GI upset. Thus, it is crucial that we induce vomiting before clinical signs manifest.

Dexmedetomidine is the only safe method that can somewhat reliably induce vomiting in cats when administered IM in the shoulder area. If no emesis occurs after 15–20 minutes, Dr. Justine Lee, a veterinary criticalist and veterinary toxicologist and the co-founder of VetGirl, recommends giving a 3.5 µg/kg IM dose. This drug is beneficial because even if the patient becomes sedated after emesis, it is reversible with atipamezole.

Hydrogen peroxide is contraindicated in cats due to a high risk of developing gastritis or hemorrhagic gastritis (higher risk than in dogs).

Clevor® is a dog-only prescription topical anti-emetic.

Apomorphine is not generally used in cats. It often causes an excitatory reaction, is unpredictable, and is usually unsuccessful in inducing vomiting. 

Correct answer: Cranial superficial epigastric vessels

Major blood vessels to be mindful of when performing surgery associated with the mammary glands of dogs and cats are as follows:

Glands 1 and 2: 
Lateral and ventral branches of the intercostals, internal thoracic, and lateral thoracic vessels

Glands 2 and 3: 
Cranial superficial epigastric vessels

Glands 4 and 5: 
Caudal superficial epigastric vessels

Ideally, in cats, you want to remove the entire chain. This owner is tying your hands. Performing single lumpectomies is not in the patient's best interest as cancer spread has likely occurred already. Ideally, removing the second and third chain and tissue close to the fourth would be most beneficial if not a complete mastectomy.

Correct answer: Female alpacas do not reach sexual maturity until 15 months of age

The farmer sees poor breeding results because of the age of the herd. In most alpacas, ovaries do not become active until 10–12 months of age, though some may start cycling as early as five months. Camelids are induced ovulators. Generally, females (much smaller than their male counterparts) should not be bred until about 18 months or older. This ensures they are at least 60% of their expected adult size, which minimizes dystocia and increases the chance of a successful pregnancy.

Male camelids have a preputial penile attachment that doesn't separate until at least 15 months of age. Before that time, they may mount. Thus, the farmer may have presumed both the males were fully capable of breeding; however, it is likely that only the older male was sexually mature.

Correct answer: Primary idiopathic seborrhea

Primary idiopathic seborrhea is a keratinization disorder. It is commonly found in American Cocker spaniels, English Springer spaniels, Bassets, Westies, Dachshunds, labs and goldens, and German shepherds.

Given the age of onset and severity of signs yet with no pruritus, this rules out sarcoptic mange, a severely pruritic mite infection. Demodicosis can cause pruritus though it doesn't always, and it should be ruled out in this patient. There is likely a secondary infection (pyoderma/dermatitis) contributing to the scaling and crusting.

While secondary infections are likely present at the time of diagnosis, Malassezia usually causes intense pruritus and is unlikely in this patient.

Thus, the lack of pruritus helps exclude scabies, allergies, and other itch-producing diseases. Because there are no systemic signs, and given the age of the pet, endocrine causes are unlikely.

However, the diagnosis of primary idiopathic seborrhea isn't made until all other possible causes have been ruled out.

Treatment is symptomatic. Treating underlying infections and synthetic vitamin A derivatives (retinoids) may be helpful. Other topical therapies, such as with douxo seborrhea spot‐on or spray or similar shampoo products, may be beneficial in minimizing oiliness and lessening the chance of secondary infections.

Correct answer: Less than 4-inch carapace length

The FDA and PHS regulate the import of any turtle with a carapace less than 4 inches, as well as turtle eggs. No turtle eggs or turtles with carapaces under 4 inches can legally be sold in the U.S. as pets. However, they can be purchased for educational purposes, exhibitions, or scientific research. Pet stores or those who illegally sell/utilize animals under the appropriate size are subject to seizure of the animals/eggs, which may be subject to humane euthanasia.

Correct answer: Xylazine 0.1–0.2 mg/kg, IV

Xylazine at doses of 0.1–0.2 mg/kg, administered intravenously, can provide adequate sedation without recumbency in alpacas/llamas. However, alpacas often need higher doses than llamas for the same duration of effect. This dose should prevent full recumbency, though it doesn't guarantee they will not kush. Higher doses, xylazine 0.3–0.4 mg/kg, IV, are needed to achieve full recumbency. 

Butorphanol at doses of 0.05–0.1 mg/kg, IM, can also be used for sedation. However, butorphanol at 0.02 mg/kg is too low a dose without additional medications to benefit you in sedation. 

Finally, ketamine 4 mg/kg, xylazine 0.4 mg/kg, and butorphanol 0.04 mg/kg, when combined IM, can be used for more prolonged procedures and will most likely result in full recumbency. 

Correct answer: > 200 flukes per animal

Fasciola hepatica, the liver fluke of ruminants, can cause chronic clinical disease, though subacute disease may occur. Animals show weight loss, anorexia, depression, anemia, hypoproteinemia, submandibular edema, dull hair coat, emaciation, and, very rarely, icterus. Fatality is uncommon in cattle because it can mount protective immunity, leading to partial resistance from future infection. This protection develops about five to six months post-exposure. Further, flukes have a short life span in cattle; thus, few remain alive after one year, unlike sheep and goats, which can have fatal illnesses more commonly. The biggest issue with cow-calf operations arises when flukes act synergistically with other infections (like nematodes) and in times of nutritional stress. The disease processes lead to prolonged calving intervals, lower-weight calves at weaning, and decreased reproductive efficiency. Further, animals may have reduced milking ability, slower return to estrus, and decreased body condition.

It is said that cattle herds with worm burdens of less than ten flukes per animal are negligible. Those with 10–40 worms per animal are possible, and those with > 40 flukes probably will have economic losses. Animals with > 200 worm burdens will manifest clinical signs. 

Correct answer: Measurable

The SMART Pneumonic can be helpful in many situations when setting goals at home and in the workplace.

• S: Specific: This would be a target or specific goal. Do not be vague. For example, you want to increase pre-anesthetic bloodwork compliance for patients undergoing routine surgery. You don't want to say that you want clients to do more bloodwork; that is too broad and not specific. It makes success in reaching the goal much more difficult and harder to justify.
• M: Measurable: When feasible, always strive to set targets that can be reached. Make them realistic but also something that can be visually seen or calculated so know that you are meeting that goal. You want to increase the number of pre-anesthetic profiles performed from 45% (where you are now) to 60% in the next one year.
• A: Attainable. Not only should there be a way to ensure you can appreciate the goal has been reached, but it needs to be realistic. You aren't going to go from 45% of patients getting pre-op bloodwork to 100% for various reasons and shouldn't expect to. However, the increase from 45–60% is likely feasible.
• R: Relevant (Related to the mission). If your goal is to improve profitability, but clients decline pre-op bloodwork (you don't make it mandatory in patients younger than six), reaching 60% may not be feasible. Another example is that your staff wants to improve the quality of medicine and ensure they practice evidence-based medicine. You elect to send several staff members to a monthly conference with a local specialty practice. However, choosing topics like how to do advanced laser surgery when you don't have a laser isn't related to your practice culture, but how to treat a newly diagnosed diabetic would be.
• T: Time Limited (Time-bound):  If we discuss a timeframe to achieve the 60% of patients doing the pre-op bloodwork, you want to limit it. One year may be too long to see if it will be profitable, but 30 days will likely not be long enough. So you want to set an acceptable, realistic time limit that works for the specific goal of interest. 

Correct answer: Notify public health officials as per your local laws

Fistulous withers, aka septic supraspinous bursitis, is a condition that leads to a chronic infection that starts in the supraspinous bursa. However, over time, it can extend into the nuchal ligament. The cause is usually undetermined and considered idiopathic though trauma can induce the lesions. Common causative etiologies include Brucella abortus (reportable and zoonotic, but not common in traumatic cases), Onchocerca cervicalis, or Actinomyces bovis. Animals will have painful swellings along the neck base or along the withers. If a draining tract hasn't already developed, aspiration and culture of the intact fluid can be performed. When the area is already open, a diagnosis must be based on clinical signs, radiographs, high proximity to cattle, or grazing on pastures used by cattle where bovine brucellosis is endemic. Obtaining serology with titers ideally > 1: 100 or 1:150 suggestive brucellosis as the cause.

Radiographs are also warranted to determine the disease extent and location of fistulous tracts. It can also rule out spread to the dorsal spinous processes, assessing for the presence of osteomyelitis (which, if present, would worsen prognosis). Ultrasound can also help determine disease spread and fistulous tracts and view the spinous processes. Further, it may help identify if any foreign bodies are inciting the bursitis. It is confirmed with serology and tissue biopsy.

Differentials include dorsal spinous process fracture of the thoracic spine, foreign body, local abscess/dermatitis, or trauma such as from a saddle.

Upon identifying fistulous withers, you must immediately contact the proper public health authorities as your local veterinary laws dictate.

Until you have confirmed the definitive agent, you must inform the owner immediately that the horse must be quarantined, precautions must be used with proper PPE of any humans handling the animal, and explain the zoonotic risk. Further, since the owner does have other susceptible species to the organism if the horse is positive for B. abortus, any susceptible species should be tested and may need to be culled depending on the location and region where she resides.

Since this is a private, non-production group of animals, consider local laws regarding whether horse treatment is permitted or if culling is required. Pending diagnostics, you can institute broad-spectrum antibiotics that will cover the majority of organisms that may be present (including secondary invaders such as Streptococcus spp, Staphylococcus species, E. coli, or Pasteurella species, among others. If proper deworming is not performed in the group of animals, treating with ivermectin in case the patient is negative for Brucella, though note that if parasite load is significant, ivermectin may precipitate clinical signs secondary to the inflammatory response from parasite die-off. Finally, consider NSAIDs to reduce pain and inflammation.

Correct answer: Acute acetaminophen toxicosis

Given this young cat's history of eating things, you would want to question the owner further to determine if anything known, likely acetaminophen or diazepam, has been dropped/ taken by anyone in the household.

While inflammatory liver disease in cats, most commonly cholangitis/cholangiohepatitis, occurs in cats, none of the choices would lead to methemoglobinuria, dyspnea, anemia, and swelling of the paws, except acetaminophen toxicity.

Acetaminophen toxicity in cats can occur with much lower doses than in dogs because cats are deficient in glucuronyl transferase. This limits the animal's ability to glucuronidate the drug and prevents metabolism after saturation via sulfation metabolism occurs. This leads to toxic metabolites. Cats may show signs at doses as low as 10–40 mg/kg, with up to 100 mg/kg known to be toxic. Cats can get renal and hepatotoxicity though dogs are more likely to develop hepatic necrosis. Methemoglobinemia with a heinz body anemia (change in hemoglobin in RBCs due to oxidative injury) confirms the diagnosis. The muddy mucus membranes arise from this methemoglobinemia.

Clinical signs may include weakness, depression, lethargy, trouble breathing, rapid breathing, icterus, vomiting, low body temperatures, dyspnea, paw or facial edema, cyanosis, and even death. Often, the first signs are hematuria and hemoglobinuria.

You can do a rapid bench-top test to differentiate normal blood vs. blood with excess methemoglobin — the abnormal blood will appear a chocolate brown vs. the normal blood. Differentials for methemoglobinemia include other toxicities, such as propylene glycol, nitrates, and local anesthetics.

Treatment is supportive, including oxygen therapy, IV fluid therapy, anti-vomiting, and anti-nausea medications. Transfusions may be needed depending on severity. N-Acetylcysteine (NAC) helps bind the toxin and minimize liver damage. The use of Denamarin as a liver protectant can be beneficial as well. 

Hepatic lipidosis or fatty liver is also common in cats but doesn't lead to heinz body anemia or methemoglobinuria. 

Correct answer: Hypothyroidism; clomipramine

This patient has a classic description that depicts hypothyroidism in dogs. Dogs seem to gain weight suddenly, and owners report no increase in food consumption. They are often heat-seekers, have exercise intolerance, may be depressed or lethargic, and may appear to have a 'tragic look' on their faces. These dogs often have alopecia, commonly truncal and symmetrical but not itchy. Some dogs may develop secondary dermatitis, but not all. This dog has a history of anxiety and takes clomipramine.

Clomipramine, glucocorticoids, aspirin, sulfonamides, phenobarbital, and several other NSAIDs have been shown to interfere with thyroid function testing.

In addition to medications altering thyroid function testing, the presence of an underlying disease can compound testing. All too often, people test for thyroid disease when a patient presents with an underlying illness, such as vomiting or diarrhea, or skin disease. Regardless, animals with underlying conditions can have falsely lowered thyroid levels, called euthyroid sick syndrome. Too many dogs are diagnosed as hypothyroid based on levels taken when sick; thus, the numbers of dogs with this condition are likely lower. Other underlying illnesses will often cause a consistent decrease in the total T3 and T4 levels proportionate to the level of severity of the disease. Dogs sick with non-thyroid illness can have TSH levels increase by 8–10%. Ft4 is less likely affected, but could be elevated or decreased. Thus, avoid testing thyroid function when sick.