Pleural effusion in cats: 82 cases (1987 to 1995).

Eighty-two cases of feline pleural effusion were identified and reviewed to assess the type of fluid, underlying disease process, predisposing conditions, historical and physical examination findings, laboratory and cytology data, response to treatment and outcome. Pertinent findings included a high occurrence of pleural effusion with mediastinal lymphoma (and other types of intrathoracic neoplasia), pyothorax, cardiomyopathy and feline infectious peritonitis virus infection. Sixteen cases, eight with chylous effusion, had no underlying disease identified. Cats with pyothorax and effusion secondary to trauma had the best prognosis for complete recovery. Otherwise, the outcome was variable and the prognosis was guarded to poor.