Zoo Biology 34: 193–197 (2015)
Percutaneous Ureteral Stent Placement for the Treatment of a Benign Ureteral Obstruction in a Sumatran Tiger (Panthera tigris sumatrae) Katie W. Delk,1* Raymund F. Wack,2 Anne Burgdorf-Moisuk,2 Carrie A. Palm,1 Allison Zwingenberger,1 Craig B. Glaiberman,3 Kenneth H. Ferguson,4 and William T. N. Culp1 1
School of Veterinary Medicine, University of California Davis, Davis, California Wildlife Health Center, University of California Davis, Davis, California 3 Sutter Health, Sacramento, California 4 Sutter Health, Davis, California 2
A 15-year-old, 113 kg intact male Sumatran tiger (Panthera tigris sumatrae) was evaluated for weight loss, polydipsia, and intermittent hematuria. The tiger was immobilized for diagnostic testing including blood work, urinalysis, and abdominal ultrasound. Laboratory testing demonstrated macro- and microhematuria, azotemia, and an increased urine protein:creatinine ratio. Abdominal ultrasound revealed bilateral ureterolithiasis as well as hydronephrosis and ureteral dilation. Ultrasonography performed 5 months later 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 calculi. Nephroureteral decompression via the placement of a stent was elected. A pigtail ureteral catheter (8.2 French diameter) was placed in the right ureter via an antegrade percutaneous approach utilizing ultrasound and ﬂuoroscopic-guidance. Following stent placement, macrohematuria resolved although microhematuria was noted in opportunistic urine samples. Five months after stent placement, the azotemia had mildly progressed, the urine protein:creatinine ratio was improved, the right hydronephrosis and hydroureter had completely resolved, and the ureteral stent remained in the appropriate position. The tiger had clinically improved with a substantial increase in appetite, weight, and activity level. Ureteral stenting allowed for nephroureteral decompression in the captive large felid of this report, and no complications were encountered. Ureteral stenting provided a minimally invasive method of managing ureteral obstruction in this patient and could be considered in future cases due to the clinical improvement and low morbidity. Zoo Biol. © 2015 Wiley Periodicals, Inc. 34:193–197, 2015.
Keywords: fluoroscopy; hydronephrosis; interventional radiology; nephroureterogram; non-domestic felid; ureterolith
STATEMENT OF THE PROBLEM A 15-year-old, 113 kg male Sumatran tiger (Panthera tigris sumatrae) was evaluated for weight loss, polydipsia, and intermittent hematuria. To allow for ultrasonographic evaluation, the tiger was immobilized with ketamine (3.5 mg/kg; Putney Inc., Portland, ME) medetomidine (0.03 mg/kg; ZooPharm, Windsor, CO), and midazolam (0.2 mg/kg; Hospira, Lake Forest, IL) given intramuscularly via a remotely delivered dart. The animal was intubated and anesthesia was maintained with isoﬂurane (USP, Piramal Healthcare Ltd, Phoenix, AZ) given to effect throughout the procedure. Imaging was performed with a 9–3 mHz ultrasound transducer (Mylab30Vet Gold, Esaote Europe B.V., Maastricht, the Netherlands) in dorsal and lateral recum-
© 2015 Wiley Periodicals, Inc.
bency. The left kidney exhibited hydronephrosis and the diameter of the proximal left ureter was 1.9 cm; a 7.4 mm This information will be presented in abstract form (250 words or less) at the annual conference of the American Association of Zoo Veterinarians in October 2014. Correspondence to: Katie W. Delk, San Diego Zoo, P.O. Box 120551, San Diego, CA 92112. E-mail: [email protected]
Received 25 August 2014; Revised 28 December 2014; Accepted 31 December 2014
DOI: 10.1002/zoo.21201 Published online 4 February 2015 in Wiley Online Library (wileyonlinelibrary.com).
194 Delk et al. calculus at the uterovesicular junction was also noted. Proximal to the stone, the distal left ureter was dilated and tortuous and measured 9 mm in diameter. The right kidney demonstrated hydronephrosis, the proximal ureter was dilated to a diameter of 8.3 mm, and there was a 7.8 mm calculus in the distal ureter at the uterovesicular junction (Fig. 1). Bilateral hydronephrosis secondary to distal ureteral calculus obstruction was diagnosed. Following the ultrasound, the tiger was returned to his enclosure and given anesthetic antagonists atipamezole (0.15 mg/kg; Zoetis, Florham Park, NJ) and ﬂumazenil (0.01 mg/kg; APP Pharmaceuticals, LLC, Schaumburg, IL) intramuscularly via hand syringe. He was extubated 7 min later and recovered smoothly. After consultation with surgical and internal medicine specialists, the decision to place ureteral stents was made to relieve the bilateral ureteral obstruction in a minimally invasive manner. DESCRIPTION OF THE PROCESS Four months later, the tiger was immobilized with ketamine (2 mg/kg), medetomidine (0.025 mg/kg), and midazolam (0.15 mg/kg) given intramuscularly via dart. The animal was intubated and anesthesia was maintained
Fig.1. Ultrasound images of the tiger of this report. A: Dilated right ureter containing calculus (white crosses) at the uretovesicular junction. B: Tortuous and dilated right ureter. Zoo Biology
with isoﬂurane given to effect throughout the procedure. Blood work and urinalysis revealed moderately elevated blood urea nitrogen (BUN) (45.8 mg/dL; reference range, 20–34 mg/dL) [Wack, 2008a] with a creatinine at the upper limit of the normal range for this species (3.5 mg/dL; reference range, 1.8–3.6 mg/dL) [Wack, 2008a], an elevated urine protein:creatinine ratio (0.97; reference range,