Radiographic, epidemiologic, and clinical aspects of simultaneous pleural and peritoneal effusions in dogs and cats: 48 cases (1982-1991).

In this study, we found that the rate at which radiographically diagnosed simultaneous pleural and peritoneal effusions (double effusion [DE]) developed was highest in dogs and cats with infectious causes of pleuritis and/or peritonitis and in those with pancreatitis. However, DE were observed more frequently in dogs and cats with neoplastic and cardiovascular diseases. Nonneoplastic liver disease was also documented as a cause of DE in the population of this study. Frequency of DE was increased in males and in animals > 6 years old. The finding of simultaneous pleural and peritoneal effusions can be considered an indicator of disease severity, and warrants a poor to grave prognosis.