A 12 year old female spayed Jack Russell Terrier presented to the Cornell University Hospital for Animals’ (CUHA) Emergency Service with a 3-day history of polyuria and polydipsia, lethargy, vomiting, diarrhea, abdominal distension, and two episodes of collapse. The patient was tachypneic, dyspneic, and tachycardic with muffled heart sounds and pulsus paradoxus. A focused ultrasound of the chest and abdomen showed tricavitary effusion. Electrocardiography showed sinus tachycardia and electrical alternans, and echocardiography revealed a large volume of pericardial effusion with tamponade. No masses were detected. Pericardiocentesis was performed, removing 165 mL of fluid. Cytology revealed chronic hemorrhage and mesothelial cells without overt cytologic atypia, compatible with reactive change. Fourteen weeks later, echocardiography revealed pericardial effusion with tamponade, and pericardiectomy was performed. Histopathology of the pericardium showed chronic diffuse thickening and fibrosis with evidence of acute and chronic hemorrhage, consistent with chronic idiopathic pericarditis.

A 10 year old female spayed Jack Russell Terrier presented to the CUHA’s Cardiology Service for a 2 week history of inappetence, exercise intolerance, severe abdominal distension that had required abdominocentesis, and one episode of collapse. Echocardiography revealed a small volume of pericardial effusion and no masses were visualized. Pericardiocentesis was performed, removing 41 mL of fluid. Cytology showed marked criteria of malignancy, with a high suspicion of mesothelioma. Two weeks later, the patient became dyspneic with abdominal distension and gastrointestinal signs, and was euthanized.

This senior seminar will discuss acute and chronic pericardial effusion and cardiac tamponade, with an emphasis on the diagnostic value of pericardial effusion cytology, and the histopathologic features of idiopathic pericarditis and mesothelioma.