Percutaneous Ureteral Stent Placement for the Treatment of a Benign Ureteral Obstruction in a Sumatran Tiger (Panthera tigris sumatrae)
A 15-year-old, 113-kg male intact Sumatran tiger (Panthera tigris sumatrae) was evaluated for weight loss, polydipsia, and intermittent hematuria. Clinical laboratory testing demonstrated macro- and microhematuria, mild azotemia, and an increased urine protein:creatinine ratio (0.97). Abdominal ultrasound revealed bilateral ureterolithiasis as well as hydronephrosis/hydroureter. As ureteral obstruction was diagnosed, treatment to relieve the obstruction via the use of ureteral stents was elected. The tiger was immobilized with ketamine (2 mg/kg), medetomidine (0.025 mg/kg), and midazolam (0.15 mg/kg) given intramuscularly via a remotely delivered dart. After the induction of anesthesia, an abdominal ultrasound scan was repeated and revealed worsening of the right-sided hydronephrosis and hydroureter and a decrease in the severity of dilation on the left side, presumably from passage of the left-sided ureteral stones. A pigtail ureteral catheter (8.2 French x 56 cm) was placed in the right ureter via a percutaneous approach, utilizing fluoroscopic guidance. The catheter was left in place as an indwelling ureteral stent. Following stent placement, macrohematuria resolved, although occasional microhematuria was noted. At follow-up examination six months after stent placement, the azotemia had mildly progressed, but the urine protein:creatinine ratio was normal (0.5), the right hydronephrosis and hydroureter had resolved, and the ureteral stent remained in the correct position. The tiger also clinically improved with increased weight and activity level. Ureteral stenting provided a minimally invasive method of managing ureteral obstruction in the captive large felid of this report and could be considered in future cases due to the clinical improvement and low morbidity.
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