NAVLE Canine Medicine and Surgery 4 — Questions and Answers
Question 1: A 3-year-old intact female Cocker Spaniel is presented with a fever, mucopurulent vaginal discharge, PU/PD, and leukocytosis. Abdominal ultrasound confirms uterine distension. What is the definitive treatment?
- Prostaglandin F2α therapy alone
- Broad-spectrum antibiotics for 4 weeks
- Ovariohysterectomy (Correct answer)
- Progesterone receptor antagonist therapy
Correct answer: Ovariohysterectomy
Ovariohysterectomy is the definitive and safest treatment for pyometra, removing the source of infection and preventing recurrence.
Question 2: A dog presents with acute epistaxis, petechiae on the gums, and prolonged bleeding after venipuncture. CBC reveals a platelet count of 8,000/μL. Coagulation times (PT and aPTT) are normal. What is the most likely diagnosis?
- Von Willebrand disease
- Immune-mediated thrombocytopenia (IMT) (Correct answer)
- Disseminated intravascular coagulation
- Rodenticide toxicosis
Correct answer: Immune-mediated thrombocytopenia (IMT)
IMT presents with severely low platelets causing mucosal bleeding and petechiae while PT and aPTT remain normal because coagulation factor function is intact.
Question 3: A 1-year-old male intact German Shepherd presents with bilateral cryptorchidism. The owner wants the dog neutered. Which statement is most accurate?
- Only the scrotal testicle needs to be removed
- Both retained and descended testicles must be removed (Correct answer)
- Cryptorchid testicles are sterile and pose no health risk
- Orchiopexy should be performed to reposition retained testicles
Correct answer: Both retained and descended testicles must be removed
Retained testicles have a 13-14 times higher risk of developing Sertoli cell tumors and testicular torsion, so both must be removed during neutering.
Question 4: A 4-year-old Border Collie presents with episodic muscle tremors, hypersalivation, and mydriasis after being on a rural property. Organophosphate toxicosis is suspected. What is the mechanism and antidote?
- Nicotinic receptor blockade; atropine
- Acetylcholinesterase inhibition; atropine and pralidoxime (Correct answer)
- GABA antagonism; diazepam
- Sodium channel blockade; lipid emulsion therapy
Correct answer: Acetylcholinesterase inhibition; atropine and pralidoxime
Organophosphates irreversibly inhibit acetylcholinesterase causing acetylcholine accumulation; atropine blocks muscarinic effects while pralidoxime reactivates the enzyme if given early.
Question 5: On thoracic auscultation of an 8-year-old Cavalier King Charles Spaniel, you hear a grade IV/VI left apical systolic heart murmur. Echocardiography shows myxomatous mitral valve disease with moderate left atrial enlargement (LA:Ao ratio 1.7). Which ACVIM staging is most appropriate?
- Stage A
- Stage B1
- Stage B2 (Correct answer)
- Stage C
Correct answer: Stage B2
Stage B2 MMVD is defined by cardiac remodeling (LA:Ao ≥1.6 or normalized left ventricular internal diameter in diastole >1.7) without clinical signs of heart failure.
Question 6: A 6-month-old Labrador Retriever puppy presents for evaluation of exercise intolerance and a loud continuous 'machinery' murmur heard best at the left heart base. What is the most likely congenital defect?
- Ventricular septal defect
- Pulmonic stenosis
- Patent ductus arteriosus (Correct answer)
- Aortic stenosis
Correct answer: Patent ductus arteriosus
Patent ductus arteriosus produces the classic continuous 'machinery' murmur due to left-to-right shunting throughout the cardiac cycle via the unclosed ductus.
Question 7: A 5-year-old Siberian Husky is presented with zinc toxicosis after ingesting pennies minted after 1982. Which hematologic finding best explains the hemolysis observed?
- Direct autoantibody binding to RBC membranes
- Heinz body formation from oxidative RBC damage (Correct answer)
- Microangiopathic RBC destruction from vasculitis
- Aplastic anemia from bone marrow suppression
Correct answer: Heinz body formation from oxidative RBC damage
Zinc causes oxidative damage to RBC membranes and hemoglobin, leading to Heinz body formation and intravascular hemolytic anemia.
NAVLE Canine Medicine and Surgery 4
A 3-year-old intact female Cocker Spaniel is presented with a fever, mucopurulent vaginal discharge, PU/PD, and leukocytosis.
Abdominal ultrasound confirms uterine distension.
What is the definitive treatment?