Spontaneous type A aortic dissection in a dog.

A 10-year-old male Cocker Spaniel was presented for evaluation of right forelimb lameness and seizure-like episodes. Panting with increased respiratory rate and opisthotonus were evident during the physical examination. Cardiac auscultation revealed a left basilar, grade III/VI systolic murmur. The dog was stabilized with diazepam, fluid therapy, and oxygen. Indirect arterial blood pressure measured in the left forelimb by Doppler technique revealed no abnormalities. Thoracic radiography indicated a noticeable bulge in the area of the ascending aortic arch. Transthoracic echocardiography revealed marked aortic dilatation with a mobile, floating tissue flap dividing the aorta into two lumens. Additional diagnostic studies (computerized tomography, cardiac catheterization, and angiography) were offered but not obtained. Medical management included therapy with enalapril and clopidogrel. Clinical signs, including the right forelimb lameness and seizures, resolved within 24 h. This report represents an unusual case of aortic dissection in a dog associated with neurological signs.