NAVLE Canine Internal Medicine 4 — Questions and Answers
Question 1: A 6-year-old Rottweiler presents with acute vomiting and melena. Gastroscopy reveals a deep ulcer in the antrum. Which drug class is most effective at preventing NSAID-induced gastrointestinal ulcers in dogs?
- H2-receptor antagonists
- Sucralfate
- Proton pump inhibitors (Correct answer)
- Bismuth subsalicylate
Correct answer: Proton pump inhibitors
Proton pump inhibitors (e.g., omeprazole) provide the most potent and sustained acid suppression and are superior to H2 blockers for preventing and treating GI ulcers.
Question 2: A 4-year-old Siberian Husky presents with PU/PD. Water deprivation test shows urine osmolality of 180 mOsm/kg after 12 hours. After desmopressin administration, urine osmolality rises to 650 mOsm/kg. What is the diagnosis?
- Nephrogenic diabetes insipidus
- Primary (psychogenic) polydipsia
- Central diabetes insipidus (Correct answer)
- Chronic renal failure
Correct answer: Central diabetes insipidus
A robust response to exogenous ADH (desmopressin) indicates intact renal tubular response, confirming central (hypothalamic/pituitary) diabetes insipidus.
Question 3: A 10-year-old mixed-breed dog presents with weight gain, alopecia, hyperpigmentation, and a pot-bellied appearance. Urine cortisol:creatinine ratio is elevated. LDDS test shows no suppression. HDDS test shows >50% suppression. What is the most likely diagnosis?
- Adrenal-dependent hyperadrenocorticism
- Pituitary-dependent hyperadrenocorticism (Correct answer)
- Iatrogenic hyperadrenocorticism
- Hypoadrenocorticism
Correct answer: Pituitary-dependent hyperadrenocorticism
Suppression on the high-dose dexamethasone suppression test (>50%) indicates the excess ACTH source is pituitary-dependent (PDH).
Question 4: A 3-year-old Soft-Coated Wheaten Terrier presents with hypoalbuminemia (1.4 g/dL), ascites, and normal liver enzymes. Protein-losing enteropathy is suspected. Which finding on intestinal biopsy would be most consistent with lymphangiectasia?
- Crypt abscesses and villous blunting
- Dilated lacteals and lipid-laden macrophages (Correct answer)
- Plasma cell and lymphocyte infiltration of the lamina propria
- Eosinophilic infiltration of the mucosa
Correct answer: Dilated lacteals and lipid-laden macrophages
Dilated lacteals with lipid-laden macrophages (lipogranulomas) are the hallmark histopathologic findings of intestinal lymphangiectasia.
Question 5: A 5-year-old male Dalmatian presents with recurrent urinary tract infections and struvite uroliths. Urate crystals are also identified on urinalysis. Which metabolic defect predisposes Dalmatians to urate urolithiasis?
- Deficiency of uricase enzyme
- Reduced hepatic conversion of uric acid to allantoin (Correct answer)
- Increased xanthine oxidase activity
- Impaired renal tubular secretion of allantoin
Correct answer: Reduced hepatic conversion of uric acid to allantoin
Dalmatians have impaired hepatic conversion of uric acid to allantoin and reduced renal tubular reabsorption of urate, leading to uric acid excretion and urate uroliths.
Question 6: An 8-year-old Cocker Spaniel presents with a chronic cough, exercise intolerance, and a loud left apical systolic murmur (grade V/VI). Thoracic radiographs show pulmonary venous congestion. Which drug is indicated to reduce preload in this patient?
- Atenolol
- Furosemide (Correct answer)
- Amlodipine
- Digoxin
Correct answer: Furosemide
Furosemide, a loop diuretic, reduces preload by promoting sodium and water excretion, relieving pulmonary venous congestion in congestive heart failure.
Question 7: A 7-year-old German Shepherd presents with bloody diarrhea and a PCV of 10%. Smear shows anemia with marked polychromasia and many erythrocyte fragments (schistocytes). Which condition is most likely?
- Immune-mediated hemolytic anemia
- Microangiopathic hemolytic anemia associated with DIC (Correct answer)
- Iron deficiency anemia
- Heinz body anemia
Correct answer: Microangiopathic hemolytic anemia associated with DIC
Schistocytes (erythrocyte fragments) result from mechanical shearing in fibrin strands during DIC, causing microangiopathic hemolytic anemia.
NAVLE Canine Internal Medicine 4
A 6-year-old Rottweiler presents with acute vomiting and melena.
Gastroscopy reveals a deep ulcer in the antrum.
Which drug class is most effective at preventing NSAID-induced gastrointestinal ulcers in dogs?