Calcium oxalate urolithiasis in Asian small-clawed otters (Amblonyx cinereus)
A 17-year-old, captive-born, ovariohysterectomized female Asian small-clawed otter (Amblonyx cinereus) was immobilized for a routine, yearly physical examination. Abdominal radiographs demonstrated large accumulations of mineral opacity in both renal pelves (staghorn calculi) and a single, large mineral opacity in the urinary bladder. Urinalysis showed evidence of cystitis, as well as calcium oxalate crystals. Urine culture and sensitivity testing revealed group D Streptococcus sp. susceptible to amoxicillin. The otter was anesthetized for a routine cystoscopy to remove the cystolith; analysis revealed it was composed of 100% calcium oxalate. This otter's renoliths were first noticed in May, 1992 and slowly progressed over the next 13 years. At no time did the patient demonstrate clinical signs of urinary tract disease, and it is currently systemically healthy. As many as 66% of captive North American population of Asian small-clawed otters may have renal calculi, and as many as 23% may have cystic calculi. The most common component of uroliths in this species is calcium oxalate. Few studies have been performed to elucidate the pathomechanism of this disease; however, intestinal hyperaborption of calcium and increased endogenous oxalate production have been suggested. It appears that some aspect of captive husbandry plays a role. There is currently no evidence that following dietary recommendations for domestic carnivores prevents or slows the progression of the disease.
Senior seminar paperSeminar SF610.1 2006 B64
Otters -- Diseases -- Case studies