Peer-reviewed veterinary case report
Perirenal hemorrhage associated with feline infectious peritonitis: a novel presentation of a classic disease.
- Journal:
- Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
- Year:
- 2025
- Authors:
- Gauthier, Madeleine I et al.
- Affiliation:
- Faculty of Veterinary Medicine · Canada
- Species:
- cat
Plain-English summary
Feline infectious peritonitis (FIP) is a serious disease caused by a mutated form of the feline coronavirus. In a study of 51 confirmed FIP cases, researchers found that five cats had bleeding around their kidneys, which had not been reported before. Some of these cats also had bleeding in other areas, including the kidneys and even the brain. The researchers believe that the bleeding might be due to inflammation of the blood vessels caused by FIP. Although this type of bleeding is rare, it is important for veterinarians to consider it when diagnosing cats with fluid buildup or other issues in the abdominal area.
Abstract
Feline infectious peritonitis (FIP), caused by a mutated biotype of feline coronavirus (FCoV;,), is a significant disease of felids. We investigated perirenal hemorrhage, an unreported lesion in FIP, through a retrospective analysis of 51 immunohistochemistry-confirmed FIP cases submitted to the Diagnostic Services Unit (DSU; University of Calgary, Calgary, Alberta, Canada) between 2010 June 30 and 2024 June 30. Five cats had perirenal hemorrhage in the right retroperitoneal space; 4 had concurrent subcapsular renal hemorrhage; and 1 had sublumbar muscle hemorrhage and hemoabdomen. One case had additional hemorrhages in the brain and cervical spinal cord. Concurrent gross lesions typical of FIP included pyogranulomatous inflammation in various organs and protein-rich cavitary effusions. Histologic lesions typical of FIP (vasculitis and pyogranulomatous inflammation) were present in the kidneys and retroperitoneal fat of 4 cases, and in 3 cases, FCoV antigen was demonstrated in the regions of hemorrhage. The exact mechanism of this hemorrhage is unknown, but we speculate that vasculitis caused by FIP is the cause. Despite the relatively low prevalence of perirenal hemorrhage in this cohort, this lesion represents a unique, previously unreported manifestation of FIP that clinicians and pathologists should be aware of and consider in the differential diagnosis for fluid accumulation or space-occupying lesions in the retroperitoneum of cats.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/40439038/