(R05) Causes of Pleural Effusion in 67 Cat - A Retrospective Study

Abstract: Pleural effusion is the abnormal accumulation of fluid in the pleural space. Data from the literature show that heart disease probably is the most frequent cause of pleural effusion in cats, however, it can vary due the prevalence of infectious diseases and the epidemiological profile of affected cats. The underlying disease is defined through analysis of cavitary liquid, clinical data and additional imaging and laboratory tests.

The objectives of this study were to carry out a retrospective review of cases of feline pleural effusion diagnosed in Brazil between 2016-2019. Our hypothesis was that mediastinal lymphoma associated with FeLV is the main cause of pleural effusions in this population. Cases were evaluated and information about sex, age, clinical signs, retrovirus status and the definitive diagnosis were collected.

A total of 67 animals were included in the study, 35 were female (52,2%) and 32 males (47,8%). Age ranged from six months to 17 years. Dyspnea was the main sign in 39 cats (58,2%), followed by anorexia in 29 cats (43,3%). Cytologic analysis resulted in 36 neoplastic (53,7%), 8 modified transudates (11,9%), 9 aseptic exudates (11,9%), 4 pure transudates (6%), 4 septic exudates (6%), 4 hemorrhagic effusion (6%) and 3 chylothorax (4,5%). Mediastinal lymphoma was the most frequent cause of pleural effusion (53,7%) and all cats were positive in the point of care FeLV antigen test. It can be concluded that the main cause of pleural effusion was mediastinal lymphoma in this population, which is probably related with the high prevalence of FeLV in the region.