Clinicopathologic and Histopathologic Renal Abnormalities in Dogs with Coccidioidomycosis.

BACKGROUND: We observed evidence of protein-losing nephropathy in some dogs with coccidioidomycosis, suggestive of immune complex glomerulonephritis (ICGN). The goal of this study was to understand the prevalence of renal histopathologic lesions and proteinuria in dogs with coccidioidomycosis.

HYPOTHESIS: Biochemical and histopathological evidence of glomerular lesions is present in dogs with coccidioidomycosis.

ANIMALS: Hundred and fifty-six dogs with naturally occurring coccidioidomycosis.

METHODS: Retrospective case series. Clinical information and results of clinicopathologic testing were retrieved from the University of California, Davis Veterinary Medical Teaching Hospital (VMTH). Microscopic sections of renal tissue procured from necropsy of dogs with coccidioidomycosis were examined to evaluate the nature and distribution of lesions.

RESULTS: A total of 156 dogs with coccidioidomycosis were identified; 87 dogs had serum biochemistry and a urinalysis performed, 17 had urine protein:creatinine ratios (UPCs), and 24 had renal tissue available for histopathology. Eleven (13%) of the 87 dogs were azotemic, 55 (63%) were proteinuric (of which 14 [25%] had clinically relevant proteinuria defined as ≥3+ or ≥500 mg/dL), and 14 dogs had UPC ≥0.5 (range, 0.5-21.5, median 4.2). Thirteen (54%) of 24 dogs had renal histopathologic lesions suggestive of ICGN. Seven of these dogs had urinalyses performed; 5 (71%) had clinically relevant proteinuria as described above. Two dogs (33%) with normal glomeruli had granulomatous nephritis, 1 of which had intralesional Coccidioides spherules.

CONCLUSIONS AND CLINICAL IMPORTANCE: Coccidioidomycosis should be considered as a possible contributor to glomerular disease in dogs. Whether similar lesions occur in other mammalian hosts, including humans, warrants further investigation.