Renal Ultrasonography Findings in Cats with Feline Infectious Peritonitis

Abstract

Feline infectious peritonitis (FIP) is a fatal disease caused by a mutated feline enteric coronavirus (FECV) that causes a wide diversity of clinical findings. Antemortem diagnosis may be challenging as the non-effusive form causes pyogranulomatous inflammation in various organs including the eye, brain, omentum, liver and kidney compared to the effusive form. Since it has been discussed that the kidney is the organ most susceptible to FIP-related lesion development, this study aimed to evaluate the renal ultrasonography findings in cats with naturally developed non-effusive FIP. Clinical and renal ultrasonographic examinations of 17 cats with compatible clinical findings that would suggest the presence of non-effusive FIP were performed with the appropriate protocol. Both cats’ kidneys were evaluated for echogenicity, size (longitudinal length), shape, presence of free fluid, if any, and echogenicity of this fluid. As a result of renal ultrasonography, it was observed that the most prominent abnormal ultrasonographic findings were cortical hyperechogenicity (11 out of 17 cats), medullary rim sign (11 out of 17 cats), renomegaly (10 out of 17 cats), pyelectasis (5 out of 17 cats), loss of corticomedullary differentiation (4 out of 17 cats) and distortion of internal architecture (4 out of 17 cats). In conclusion, it was observed that morphological and parenchymal alterations occur in the renal ultrasonographic evaluation in cats with non-effusive FIP, and renal ultrasonography could provide useful clinical information in evaluating the clinical reflection of vasculitis due to FIP. Although these abnormal renal ultrasonography findings were not specific for FIP, it was concluded that the combination of the observed ultrasonographic findings and other compatible clinical findings and their evaluation together can be used to increase the index of suspicion for antemortem FIP infection.