Feline enteric coronavirus (FeCV) is especially contagious and present throughout the domestic cat population. Feline infectious peritonitis virus (FIPV) is considered to be a mutated form of FeCV. Risk factors for FIP include cats living in multicat households or a cattery, being sexually intact, being less than 5 years of age, and being purebred. There are two forms of FIP that have been described. An effusive form is an immune-mediated vasculitis with the subsequent loss of protein-rich fluid into such areas as the pleural or peritoneal cavities. The non-effusive form involves pyogranulomatous or granulomatous inflammation in multiple organs. This study was a retrospective review of 16 cases analyzing abdominal ultrasonographic results where necropsy or findings were highly suggestive of FIP. This study found that 75% of diagnosed FIP cases had abdominal effusion. Renomegaly was also a frequent finding in this study, while the majority of the feline livers examined in this study were described as normal on ultrasound. In the majority of cases with FIP, the spleen also had a normal ultrasonographic appearance while the spleen is found to be diffusely affected. Almost half of the study population did not have abdominal lymphadenopathy. None of the ultrasonographic findings were found to be specific for FIP, a combination of findings should increase the index of suspicion for FIP when considered along with appropriate clinical signs. On the other hand, a normal abdominal ultrasound does not exclude the possibility of FIP. [VT]
Goodson TL, Randell SC, Moore LE: Feline infectious peritonitis, Compend Contin Educ Vet 31, 2009.