NAVLE Canine Medicine and Surgery Questions and Answers — Questions and Answers
Question 1: A 5-year-old, male neutered Doberman Pinscher presents for evaluation. Echocardiography reveals a dilated left ventricle with decreased fractional shortening. The owner reports episodes of coughing and exercise intolerance. Which of the following long-term oral medications has been shown to delay the onset of clinical signs and extend the life of Dobermans in the occult stage of this disease?
- Furosemide
- Enalapril
- Pimobendan (Correct answer)
- Spironolactone
Correct answer: Pimobendan
Pimobendan, an inodilator, has been proven to delay the onset of congestive heart failure and prolong survival in Doberman Pinschers with preclinical (occult) dilated cardiomyopathy (DCM). While furosemide, enalapril, and spironolactone are used to manage congestive heart failure once it develops, pimobendan is the key therapy for the occult stage.
Question 2: A 10-week-old female Maltese puppy is presented for her first physical examination. On auscultation, you detect a continuous, 'machinery-like' murmur, heard best over the left heart base. The puppy is otherwise bright and alert. Which of the following is the most likely diagnosis?
- Ventricular Septal Defect
- Patent Ductus Arteriosus (Correct answer)
- Pulmonic Stenosis
- Mitral Valve Dysplasia
Correct answer: Patent Ductus Arteriosus
A continuous, machinery-like murmur heard best at the left heart base in a young dog is pathognomonic for a left-to-right shunting Patent Ductus Arteriosus (PDA). This occurs because the ductus arteriosus, a vessel that bypasses the lungs in the fetus, fails to close after birth, causing a constant flow of blood from the high-pressure aorta to the lower-pressure pulmonary artery.
Question 3: A 4-year-old female spayed Standard Poodle presents with a 2-day history of lethargy, vomiting, and weakness. Physical exam reveals pale mucous membranes and tachycardia. A CBC shows a hematocrit of 15% with marked spherocytosis and autoagglutination. What is the MOST critical initial component of immunosuppressive therapy for this dog's condition?
- Azathioprine
- Cyclosporine
- Mycophenolate mofetil
- Glucocorticoids (Correct answer)
Correct answer: Glucocorticoids
The clinical signs and laboratory findings are highly suggestive of Immune-Mediated Hemolytic Anemia (IMHA). The cornerstone and first-line treatment for IMHA is aggressive immunosuppression, which is most rapidly and effectively achieved with glucocorticoids (e.g., prednisone or dexamethasone). While other immunosuppressive drugs like azathioprine, cyclosporine, and mycophenolate are often used as adjuncts, they are not the primary, initial therapy.
Question 4: Which of the following findings on an ACTH stimulation test is most consistent with a diagnosis of typical hypoadrenocorticism (Addison's disease) in a dog?
- Low baseline cortisol with an exaggerated response post-ACTH
- High baseline cortisol with a minimal response post-ACTH
- Normal baseline cortisol with an exaggerated response post-ACTH
- Low baseline cortisol with a minimal to no response post-ACTH (Correct answer)
Correct answer: Low baseline cortisol with a minimal to no response post-ACTH
The definitive diagnosis of hypoadrenocorticism is made with an ACTH stimulation test. Dogs with Addison's disease have adrenal glands that cannot produce cortisol, so both the baseline (pre-ACTH) cortisol level and the post-ACTH cortisol level will be low, showing a minimal or flat-line response to stimulation.
Question 5: A 7-year-old, neutered male Golden Retriever is presented with a chief complaint of weight gain, lethargy, and a 'rat tail' (alopecia on the tail). Physical examination reveals a dull coat, truncal alopecia, and mild obesity. Which of the following clinicopathologic abnormalities would be most supportive of a diagnosis of hypothyroidism?
- Hypercholesterolemia (Correct answer)
- Hyperglycemia
- Low BUN and creatinine
- Increased ALT and ALKP
Correct answer: Hypercholesterolemia
The clinical signs described are classic for canine hypothyroidism. Due to the decreased metabolic rate associated with hypothyroidism, hypercholesterolemia is a very common finding on a serum biochemistry panel, present in about 75% of cases. While a mild, non-regenerative anemia may also be seen, hypercholesterolemia is the most consistent biochemical abnormality.
Question 6: A 2-year-old Miniature Schnauzer is presented to the emergency clinic with acute onset of vomiting and profuse hemorrhagic diarrhea, described as 'raspberry jam' in appearance. The dog is tachycardic, has weak pulses, and a PCV of 62% with normal total solids. What is the most critical initial treatment for this patient?
- Oral metronidazole
- Aggressive intravenous fluid therapy (Correct answer)
- Subcutaneous fluids and anti-emetics
- Immediate blood transfusion
Correct answer: Aggressive intravenous fluid therapy
This presentation is classic for Acute Hemorrhagic Diarrhea Syndrome (AHDS), formerly known as hemorrhagic gastroenteritis (HGE). The hallmark is a markedly elevated PCV due to profound hemoconcentration from fluid loss into the gut. The most critical, life-saving initial treatment is aggressive intravenous fluid therapy to correct hypovolemic shock and dehydration. Subcutaneous fluids are inadequate for this degree of fluid loss.
NAVLE Canine Medicine and Surgery Questions and Answers
A 5-year-old, male neutered Doberman Pinscher presents for evaluation.
Echocardiography reveals a dilated left ventricle with decreased fractional shortening.
The owner reports episodes of coughing and exercise intolerance.
Which of the following long-term oral medications has been shown to delay the onset of clinical signs and extend the life of Dobermans in the occult stage of this disease?