NAVLE Canine Medicine and Surgery 5

Question 1

A dog presents with a rapidly growing subcutaneous mass on the trunk. Fine needle aspirate shows granules that stain metachromatically with toluidine blue. What is the diagnosis and recommended initial treatment?

Accepted Answer

Mast cell tumor; wide surgical excision with 2-3 cm margins

Answer

Mast cell tumors contain metachromatic granules and require wide surgical margins of 2-3 cm laterally and one fascial plane deep to reduce local recurrence.

Question 2

A 2-year-old female Weimaraner presents with recurrent urinary tract infections despite appropriate antibiotic therapy. Vaginal examination reveals a band of tissue at the vestibulovaginal junction. What is the likely diagnosis?

Accepted Answer

Vestibulovaginal stenosis (vaginal stricture)

Answer

Vestibulovaginal stenosis creates a pool of urine anterior to the stricture that acts as a reservoir for bacterial colonization, causing recurrent UTIs.

Question 3

A dog is diagnosed with leptospirosis after exposure to wildlife. Which organ system is MOST commonly affected, leading to the clinical presentation seen in acute leptospirosis?

Accepted Answer

Renal and hepatic systems

Answer

Leptospira organisms have a particular tropism for renal tubular epithelium and hepatocytes, leading to acute kidney injury and hepatopathy as the dominant clinical syndrome.

Question 4

A 9-year-old male neutered Golden Retriever presents with progressive forelimb lameness. Radiographs of the shoulder reveal a 'moth-eaten' lytic lesion of the proximal humerus with periosteal reaction and cortical destruction. What is the most likely diagnosis and treatment?

Accepted Answer

Osteosarcoma; limb amputation with adjuvant carboplatin chemotherapy

Answer

Osteosarcoma most commonly affects the proximal humerus in large breeds; amputation combined with carboplatin or doxorubicin chemotherapy provides the best median survival.

Question 5

A 7-year-old Poodle presents with a PCV of 18%, MCV of 110 fL (macrocytosis), and a low serum cobalamin (B12). What is the most likely cause?

Accepted Answer

Cobalamin deficiency causing megaloblastic anemia

Answer

Cobalamin deficiency impairs DNA synthesis in RBC precursors, causing large, immature red cells (macrocytosis) and non-regenerative megaloblastic anemia.

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE Canine Medicine and Surgery 5