Peritoneal effusion in cats: 65 cases (1981-1997)

Objective-To determine signalment, diagnoses, presence of effusions in mult iple sites, and outcome in cats with peritoneal effusion. Design-Retrospective case series. Animals-65 cats. Procedure-Medical records from 1981 to 1997 were reviewed to obtain informa tion on cats with peritoneal effusion identified on physical examination, r adiographs, abdominal ultrasonograms, or at necropsy. Results-Conditions most commonly associated with peritoneal effusion in cat s, in order of frequency, were cardiovascular disease, neoplasia, hepatic d isease, renal disease, feline infectious peritonitis, peritonitis attributa ble to other causes, and urinary tract trauma. Dilated cardiomyopathy (DCM) was the most common disease associated with peritoneal effusion; however, DCM was diagnosed in most of these cats before taurine deficiency was found to be a primary cause of this form of cardiomyopathy in cats. Neoplasia wa s the most common cause after 1987. Right-sided congestive heart failure wa s the most commonly associated disorder in cats < 1 year old, whereas neopl astic disease was more common with increasing age. Most effusions were dete cted during the initial physical examination and were modified transudates. Peritoneal effusion was commonly accompanied by fluid accumulation elsewhe re, particularly pleural effusion. The prognosis for a cat with abdominal e ffusion in this study was poor (mean survival time, 21 days; range, 1 to 35 0 days; median, 2.5 days). Clinical Implications-The primary differential diagnosis for peritoneal eff usion in cats is neoplastic disease in older cats and right-sided heart fai lure in kittens. Diseases associated with peritoneal effusion generally hav e poor prognoses.