NAVLE Canine Medicine and Surgery 2 — Questions and Answers
Question 1: A 7-year-old male intact Golden Retriever presents with a firm, painless swelling at the base of the tail. Cytology reveals sheets of round cells with prominent nucleoli and vacuolated cytoplasm. What is the most likely diagnosis?
- Perianal adenoma
- Anal sac adenocarcinoma (Correct answer)
- Perianal adenocarcinoma
- Mast cell tumor
Correct answer: Anal sac adenocarcinoma
Anal sac adenocarcinoma presents as a firm mass in the anal sac region and cytology shows epithelial cells with malignant features; it is not hormone-dependent unlike perianal adenomas.
Question 2: A dog is presented with acute onset of non-ambulatory tetraparesis following a traumatic event. Spinal radiographs reveal atlantoaxial subluxation. What is the definitive treatment of choice?
- Strict cage rest alone
- Corticosteroid therapy
- Surgical stabilization of the atlantoaxial joint (Correct answer)
- Cervical splinting with a neck brace
Correct answer: Surgical stabilization of the atlantoaxial joint
Surgical stabilization via ventral fixation or dorsal wiring provides definitive correction of atlantoaxial subluxation, which otherwise risks life-threatening spinal cord compression.
Question 3: Which electrolyte abnormality is most commonly associated with hypoadrenocorticism (Addison's disease) in dogs?
- Hypernatremia and hypokalemia
- Hyponatremia and hyperkalemia (Correct answer)
- Hypercalcemia and hyperphosphatemia
- Hypomagnesemia and hypochloremia
Correct answer: Hyponatremia and hyperkalemia
Lack of mineralocorticoids in Addison's disease leads to sodium wasting and potassium retention, producing hyponatremia and hyperkalemia with a Na:K ratio below 27.
Question 4: A 4-year-old Labrador Retriever undergoes a routine CBC and is found to have a hematocrit of 20%, reticulocytosis, and spherocytes on blood smear. The Coombs test is positive. What is the most appropriate initial treatment?
- Blood transfusion only
- Splenectomy
- Immunosuppressive doses of prednisone (Correct answer)
- Intravenous iron supplementation
Correct answer: Immunosuppressive doses of prednisone
Immune-mediated hemolytic anemia is treated primarily with immunosuppressive corticosteroids such as prednisone to halt antibody-mediated red cell destruction.
Question 5: A 9-year-old spayed female Boxer is presented with episodic weakness, syncope, and a heart rate of 40 bpm. ECG reveals a P wave with no associated QRS complex occurring at irregular intervals. What is the diagnosis?
- Atrial fibrillation
- Third-degree (complete) AV block (Correct answer)
- Sick sinus syndrome
- Ventricular tachycardia
Correct answer: Third-degree (complete) AV block
Third-degree AV block is characterized by complete dissociation of P waves and QRS complexes with a slow escape rhythm, causing bradycardia and syncope.
Question 6: A German Shepherd presents with chronic intermittent diarrhea, weight loss, and a serum cobalamin level of 85 ng/L (reference: 251-908). Serum folate is markedly elevated. What is the most likely diagnosis?
- Exocrine pancreatic insufficiency
- Inflammatory bowel disease
- Small intestinal bacterial overgrowth (Correct answer)
- Protein-losing enteropathy
Correct answer: Small intestinal bacterial overgrowth
Small intestinal bacterial overgrowth causes bacteria to consume cobalamin (lowering serum levels) while producing excess folate, resulting in low cobalamin and high folate.
Question 7: During abdominal exploratory surgery in a dog, you discover a mesenteric mass with multiple satellite nodules on the intestinal serosa. Histopathology returns as gastrointestinal stromal tumor (GIST). Which treatment has shown the most promise?
- Radiation therapy alone
- Combination chemotherapy with doxorubicin and cyclophosphamide
- Surgical resection combined with toceranib phosphate (Palladia) (Correct answer)
- Carboplatin monotherapy
Correct answer: Surgical resection combined with toceranib phosphate (Palladia)
GISTs overexpress c-KIT receptor tyrosine kinase, making them responsive to toceranib (a KIT inhibitor), and surgical debulking combined with toceranib improves outcomes.
NAVLE Canine Medicine and Surgery 2
A 7-year-old male intact Golden Retriever presents with a firm, painless swelling at the base of the tail.
Cytology reveals sheets of round cells with prominent nucleoli and vacuolated cytoplasm.
What is the most likely diagnosis?