title: Bilateral uric acid nephrolithiasis and ureteral hypertrophy in a free-ranging river otter (Lontra canadensis).
abstract: We report the first case of uric acid nephrolithiasis in a free-ranging river otter (Lontra canadensis). A 7 yr old male river otter collected from the Skagit River of western Washington (USA) had bilateral nephrolithiasis and severely enlarged ureters (one of 305 examined [0.33%]). The uroliths were 97% uric acid and 3% protein. Microscopic changes in the kidney were confined to expansion of renal calyces, minor loss of medullary tissue, and multifocal atrophy of the cortical tubules. No inflammation was observed in either kidney or the ureters. The ureters were enlarged due to marked hypertrophy of smooth muscle plus dilation of the lumen. Fusion of the major calyces into a single ureteral lumen was several cm distal to that of two adult male otters used as histopathologic control specimens. This case report is part of a large contaminant study of river otters collected from Oregon and Washington. It is important to understand diseases and lesions of the otter as part of our overall evaluation of this population.
authors.affiliation: USGS-Forest and Range Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon 97331, USA. robert_grove@usgs.gov
authors.forename: Robert A
authors.initials: RA
authors.lastname: Grove
authors.forename: Rob
authors.initials: R
authors.lastname: Bildfell
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Henny
authors.forename: Donald R
authors.initials: DR
authors.lastname: Buhler
mesh_terms: D000818:Animals; D000835:Animals, Wild; D006984:Hypertrophy / Q000662:veterinary; D007668:Kidney / Q000473:pathology; D007669:Kidney Calculi / Q000473:pathology / Q000662:veterinary*; D008297:Male; D010041:Otters; D014513:Ureter / Q000473:pathology*; D014527:Uric Acid / Q000032:analysis; D014861:Washington; D014873:Water Pollutants / Q000009:adverse effects*
chemical_list: D014873:Water Pollutants; D014527:Uric Acid