Pericardial effusion caused by Feline Infectious Peritonitis in a cat

Authors: Lim C, Kennedy A, Brain P, Kopecny L, White J
Publication: Australian Veterinary Practitioner, Volume 54, Issue 1, pp 6-15, Mar 2024
Publisher: Australian Veterinary Association

Animal type: Cat
Article class: Clinical Article

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Abstract:

Case report: A 3-year-old male neutered British shorthair cat was referred for investigation of tachypnea, lethargy and hyporexia. Abnormalities detected on routine haematology and biochemical analyses included a microcytic, normochromic regenerative anaemia, moderate hyperbilirubinaemia, and an albumin to globulin ratio (A:G) of 0.56. Thoracic imaging revealed marked pericardial effusion, moderate pleural effusion, marked cranial mediastinal lymphadenopathy, and a mass in the right jugular vein and cranial vena cava. Pericardial fluid analysis revealed a grossly yellow, opaque, high-protein mixed cellularity exudate; with no growth on bacterial culture. Direct immunofluorescence (DIFA) against feline coronavirus (FCoV) was positive on the pericardial fluid, supporting a diagnosis of effusive feline infectious peritonitis (eFIP). The cat was treated with three days of intravenous remdesivir before transitioning to oral GS-441524. Within 48 hours of starting antiviral treatment, significantly improved appetite and demeanour, and resolution of tachypnea were observed. Serial sonographic assessments noted reductions in pericardial and pleural effusions, and static mild peritoneal effusion. Concurrent bloodwork improvements were noted (reduced A:G; improved hyperbilirubinemia and anaemia). On day 18, the cat presented for lethargy, hyporexia and dyspnoea, with pericardial, pleural and peritoneal effusions. Thoracocentesis revealed a grossly cloudy yellow, protein-rich pleural effusion; semi-quantitative FCoV PCR on the fluid was negative. Following initial stabilisation with oxygen and furosemide, the cat experienced acute respiratory deterioration and cardiopulmonary arrest.

Conclusions: This is the first report detailing clinical progression while receiving nucleoside analogue treatments in a cat with eFIP presenting with marked intrathoracic lymphadenomegaly and pericardial effusion. Effusive FIP should be considered as a differential diagnosis in young cats presenting with pericardial effusion.

Keywords: pericardial effusion, feline infectious peritonitis, feline coronavirus, direct immunofluorescence, remdesivir, GS-441524, nucleoside analogue

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