A 17-week-old spayed female Sphinx was referred for evaluation because of a 3-day history of inappetence, lethargy, and vomiting and a 1-day history of small bowel diarrhea. The kitten had undergone routine elective ovariohysterectomy, with no reported complications, at approximately 14 weeks of age. Prior to ovariohysterectomy, no abnormal clinical signs were evident, and the kitten was reported to be bright and active. The kitten's vaccination status was current, and there was no known dietary indiscretion or exposure to toxins. The kitten was housed indoors with no other pets.
Evaluation by the referring veterinarian the day prior included a CBC, serum biochemical analysis, and urinalysis. The CBC revealed monocytosis (850 monocytes/μL; reference range, 500 to 670 monocytes/μL), but other findings were unremarkable. Serum biochemical analysis revealed mildly high BUN concentration (37 mg/dL; reference range, 16 to 33 mg/dL) and normal creatinine concentration (0.8 mg/dL; reference range, 0.6 to 1.6 mg/dL); the remainder of the findings was unremarkable. Urine specific gravity was 1.060; other results of urinalysis were considered normal. Abdominal ultrasonography revealed an enlarged left kidney (length, 4.71 cm), with moderate pyelectasia (renal pelvis measured 6 mm in height on sagittal images) and a distended proximal portion of the left ureter (diameter, 5 mm).
The kitten was referred for further evaluation. On initial evaluation, the kitten was quiet and alert; rectal temperature (38.3°C [101°F]), pulse rate (220 beats/min), and respiratory rate (40 breaths/min) were within reference ranges. The kitten weighed 1.3 kg (2.86 lb) and had a body condition score of 4 on a scale from 1 to 9. Abdominal palpation revealed a markedly enlarged left kidney (approx 4.5 cm), and a pain response was elicited during renal palpation. A healed 1-cm laparotomy scar was visible on the caudal ventral abdominal midline. No other abnormalities were detected during physical examination.
A blood sample was collected for hematologic evaluation and serum biochemical analysis. A CBC revealed leukopenia (3,340 leukocytes/μL; reference range, 4,500 to 14,000 leukocytes/μL), with mild neutropenia (2,839 neutrophils/μL; reference range, 3,000 to 10,500 neutrophils/μL) and lymphopenia (134 lymphocytes/μL; reference range, 1,000 to 7,000 lymphocytes/μL). Serum biochemical analysis findings included hypoproteinemia (6.4 g/dL; reference range, 6.8 to 8.3 g/dL), hypoglobulinemia (2.4 mg/dL; reference range, 2.8 to 5.4 mg/dL), high aspartate aminotransferase activity (83 U/L; reference range, 17 to 58 U/L), high creatine kinase activity (5,190 U/L; reference range, 73 to 260 U/L), and high alkaline phosphatase activity (100 U/L; reference range, 14 to 71 U/L). The kitten was nonazotemic (BUN concentration, 27 mg/dL [reference range, 18 to 33 mg/dL]; creatinine concentration, 1.1 mg/dL [reference range, 1.1 to 2.2 mg/dL]), although an increase in serum creatinine concentration (previously 0.8 mg/dL) was noted. Urine specific gravity was 1.015, with no other abnormalities detected by urinalysis. Results of bacteriologic culture of urine were negative.
The kitten was hospitalized and administered lactated Ringer's solution (continuous rate IV infusion at 3 mL/kg/h [1.4 mL/lb/h]), hydromorphone hydrochloride (0.05 mg/kg [0.023 mg/lb], IV, q 6 h), ampicillin-sulbactam (21 mg/kg [9.55 mg/lb], IV, q 8 h), and ondansetron (0.5 mg/kg [0.23 mg/lb], IV, q 12 h). The kitten's appetite was considered normal. No vomiting was observed overnight; however, moderate small bowel diarrhea continued.
Abdominal ultrasonography was performed the next day and revealed renomegaly and moderate hydronephrosis of the left kidney; the left renal pelvis measured 0.9 × 1.9 cm on sagittal images and 1.6 × 2.2 cm on transverse images (Figure 1). The proximal portion of the left ureter was tortuous and moderately dilated (diameter, 3.2 mm) from the origin to the level of the midureter, where it abruptly tapered (diameter, 0.9 mm). No discrete cause of obstruction was observed. Diffusely hyperechoic small intestinal mucosa was also noted. There were no other ultrasonographic abnormalities. On the basis of these findings, the kitten was suspected to have a ureteral obstruction at the level of the left midureter. Given the recent ovariohysterectomy, iatrogenic ureteral ligation was a primary differential diagnosis. The kitten was hospitalized overnight; the previously initiated treatment was continued, aside from antimicrobial treatment, which was discontinued. The kitten continued to have a good appetite and had 2 normal bowel movements.
The kitten was anesthetized on the third day of hospitalization for exploratory laparotomy. Hydromorphone hydrochloride (0.05 mg/kg, SC, once) and atropine sulfate (0.02 mg/kg [0.009 mg/lb], SC, once) were administered as premedications, and anesthesia was induced with propofol (1.7 mg/kg [0.77 mg/lb], IV), midazolam (0.2 mg/kg [0.09 mg/lb], IV), and ketamine hydrochloride (2.3 mg/kg [1.05 mg/lb], IV). An endotracheal tube was placed, and anesthesia was maintained via inhalation of isoflurane in oxygen; the kitten was also administered midazolam (loading dose of 0.2 mg/kg, IV, followed by continuous rate infusion at 0.2 mg/kg/min, IV), dopamine hydrochloride (continuous rate infusion at 10 μg/kg/min [4.5 μg/lb/min], IV), mannitol (continuous rate infusion at 100 mg/kg/h [45.45 mg/lb/h], IV), and lactated Ringer's solution (continuous rate infusion at 11.5 mL/kg/h [5.23 mL/lb/h], IV). The kitten also received cefazolin sodium (22 mg/kg [10 mg/lb], IV) once during surgery.
The kitten was placed in dorsal recumbency, and the ventral aspect of the abdomen was shaved and aseptically prepared for surgery. A 10-cm ventral midline celiotomy was performed, and the abdomen was explored. The left kidney was grossly enlarged, and the distal portion of the ureter was irregular and had evidence of fibrosis (Figure 2), with adhesions to the mesentery and pancreas. There was no visible suture material (the suture type used during the ovariohysterectomy was not known) or other extraluminal obstruction that could be removed.
An 18-gauge over-the-needle cathetera was inserted into the caudal pole of the left kidney equidistant ventrally and dorsally and directed to the renal pelvis. The needle was removed from the catheter. Urine was obtained from the catheter for bacteriologic culture, and a syringe with a mixture of iodinated contrast mediumb and saline (0.9% NaCl) solution (1:1) was attached to the catheter. The mixture of contrast medium and saline solution was injected into the renal pelvis, and the renal pelvis and proximal portion of the ureter were observed with fluoroscopy. Contrast medium did not pass beyond the region of the midureter.
Having confirmed nonpatency of the left ureter, the placement of a subcutaneous ureteral bypassc system (as described by Berent et ald) was elected to provide renal decompression. A 0.035-inch J-tipped guide wiree was placed into the 18-gauge catheter and coiled in the renal pelvis (Figure 3). The 18-gauge catheter was removed over the guide wire. A 6.5F pigtail locking-loop nephrostomy tubec was placed over the guide wire into the renal pelvis. The suture present on the exposed end of the nephrostomy tube was pulled tight to lock the tube, and a hemostat was placed across the suture to maintain the lock. The cuff of the nephrostomy tube was then glued to the capsule of the kidney at the caudal pole.
A purse-string suture was placed into the left apex of the urinary bladder, and a stab incision was made inside the purse string. A 7F cystostomy tubec was inserted into the stab incision, and the purse-string suture was secured. The cuff of the cystostomy tube was placed into apposition with the bladder wall and was glued to the bladder wall. Four sutures of 4–0 polydioxanone were also placed between the cuff and the bladder wall to further secure the cystostomy tube.
The ends of both the nephrostomy tube and cystostomy tube (Figure 3) were tunneled through the body wall; the nephrostomy tube was tunneled caudally and the cystostomy tube was tunneled cranially to decrease the risk of kinking. The nephrostomy tube was shortened by incising the tubing surrounding the locking suture, and a subcutaneous access portc was attached to the nephrostomy tube. A boot present on the nephrostomy tube was pushed onto the male adapter of the port to secure the tube more effectively. The cystostomy tube was also attached to the subcutaneous port, and a boot was secured in similar fashion. Injection of contrast medium into the port, combined with fluoroscopic evaluation, confirmed patency of the nephrostomy and cystostomy tubing and demonstrated that no leaking from the subcutaneous ureteral bypass system was present (Figure 4). The abdomen was copiously lavaged with saline solution and suctioned prior to routine closure of the linea alba, subcutaneous tissue, and skin layers. A 3.5F red rubber urinary catheterf was placed into the urethra and bladder, secured with nylon sutures, and attached to a closed urinary catheter system prior to recovery of the kitten from anesthesia. The catheter was placed to allow recording of urine output and to minimize expansion of the urinary bladder in the immediate postoperative period. Postoperative radiography revealed appropriate positioning of the subcutaneous ureteral bypass system (Figure 5).
After recovery from anesthesia, a venous blood sample was collected; blood gas and electrolyte analyses revealed marked hypokalemia (2.5 mmol/L; reference range, 3.6 to 4.9 mmol/L). Packed cell volume was 32% (reference range, 25% to 45%), and plasma total protein concentration was 5.9 g/dL. The kitten was treated with lactated Ringer's solution (continuous rate infusion, 4.6 mL/kg/h [2.1 mL/lb/h], IV) supplemented with potassium chloride (60 mEq/L). The kitten was also administered hydromorphone hydrochloride (0.05 mg/kg, IV, q 6 h) for analgesia and ondansetron (0.5 mg/kg, IV, q 12 h). After 4 hours of fluid therapy, serum potassium concentration was 3 mmol/L. The kitten had no postoperative complications, and it seemed bright and was eating and drinking several hours after surgery.
The morning after surgery, the kitten continued to recover and maintained a normal mentation, had an excellent appetite, and defecated formed feces; urine output was approximately 6.4 mL/kg/h (2.91 mL/lb/h). Serum biochemical analysis revealed improved potassium status (3.6 mmol/L) and mild hyperphosphatemia (phosphorus concentration, 7 mg/dL; reference range, 3.2 to 6.3 mg/dL). Other acid-base and electrolyte variables were within reference limits, as were BUN concentration (28 mg/dL) and creatinine concentration (0.8 mg/dL). The PCV was 30%, and plasma total protein concentration was 6.5 g/dL. The incision site was non-inflamed, with no signs of discharge or dehiscence, and no signs of pain were elicited on abdominal palpation. The analgesic agent was changed from hydromorphone hydrochloride to buprenorphine hydrochloride (0.01 mg/kg [0.005 mg/lb], IV, q 6 h), and fluid therapy with lactated Ringer's solution (continuous rate infusion at 3 mL/kg/h, IV) supplemented with potassium chloride (40 mEq/L) was continued. Urine output was approximately 5.8 mL/kg/h (2.64 mL/lb/h). The kitten was provided free access to water and frequent feedings of a maintenance canned and kibble diet. The kitten remained hypothermic throughout the day, with a rectal temperature of 36°C (96.8°F), despite supplemental heat administration.
The second day after surgery, fluid therapy with lactated Ringer's solution was decreased (continuous rate infusion, 1.5 mL/kg/h [0.68 mL/lb/h], IV, supplemented with potassium chloride [50 mEq/L]). The urine output decreased from 3.8 to 1.5 mL/kg/h (1.73 to 0.68 mL/lb/h), but the kitten's weight remained stable. Hematologic analysis revealed that the PCV was 29%, and plasma total protein concentration was 6.5 g/dL. The urinary catheter was removed after the kitten chewed through the connective tubing. Despite intake of resting energy requirements, the kitten remained hypokalemic (2.9 mmol/L). Thereafter, the kitten was offered kibble free choice. Other acid-base and electrolyte variables were within reference ranges, and the kitten remained nonazotemic.
The third day after surgery, IV fluid therapy and ondansetron administration were discontinued. The kitten had no signs of discomfort while being treated with buprenorphine hydrochloride (0.01 mg/kg, transmucosally, q 8 h). The kitten remained hypokalemic (2.7 mmol/L), with no other serum biochemical abnormalities. Given persistent hypokalemia, supplementation with potassium gluconateg was initiated (0.7 mEq/kg, PO, q 24 h). The kitten continued to eat and drink well; urination and defecation were considered normal. Hematologic analysis revealed that the PCV was 26%, and plasma total protein concentration was 6.1 g/dL. Recheck focal urinary tract ultrasonography was performed, which revealed complete resolution of the left-sided hydronephrosis and left ureteral dilation (Figure 6). The subcutaneous ureteral bypass system was in an appropriate position. No free abdominal or retroperitoneal fluid was present. The incision site remained non-inflamed with no signs of discharge or dehiscence, but the kitten developed acute fluctuant and nonpainful focal swelling surrounding the port site that was presumed to be a seroma.
The fourth day following surgery, the kitten was bright and active and maintained a rectal temperature between 36.1° and 38.3°C (97° and 101°F) without thermal support. It was eating and drinking well with seemingly normal defecation and urination. Slight progression of the swelling surrounding the port was noted, but the kitten appeared comfortable, and the incision site seemed to be healing normally. Hematologic analysis revealed that the PCV was 29% and plasma total protein concentration was 6.8 g/dL. Serum electrolyte concentrations were within reference limits, and potassium concentration was 3.6 mmol/L.
Results of a recheck CBC indicated that the kitten had leukocytosis (total WBC count, 19,590 WBCs/μL; neutrophil count, 9,717 neutrophils/μL; lymphocyte count, 8,522 lymphocytes/μL; and monocyte count, 646 monocytes/μL [reference range, 50 to 600 monocytes/μL]). Regenerative anemia was also present (Hct, 32.3% [reference range, 30% to 50%]; reticulocyte count, 351,000 reticulocytes/μL [reference range, 7,000 to 60,000 reticulocytes/μL]; and plasma total protein concentration, 7.0 g/dL). Bacteriologic culture of the urine collected directly from the renal pelvis during surgery yielded no growth.
The kitten was discharged from the hospital to the owners on the fifth day after surgery. The owners reported that the kitten continued to have a good appetite and normal bowel movements for the first 2 days after surgery, but then developed small amounts of mixed-bowel diarrhea with mucus 2 to 3 times/d and subjectively seemed depressed. The diet was adjusted to a kitten maintenance diet, and within 1 day after the diet change, the kitten's feces became normally formed and energy level improved dramatically; no immediate recheck examination was conducted.
The kitten was reevaluated 3 weeks following surgery. The owners reported that the kitten was doing well at home. The kitten weighed 2.05 kg (4.51 lb) and had a body condition score of 4 on a scale from 1 to 9. Physical examination findings were within normal limits, and the previously noted swelling around the port had resolved. Findings on recheck focal abdominal ultrasonographic evaluation were similar to those of previous evaluations: left renomegaly (length, 4.6 cm) with scant pelvic dilation around the nephrostomy pigtail tubing was noted. Hematologic analyses revealed that the PCV was 38% and plasma total protein concentration was 7.5 g/dL. Results of serum biochemical analyses were unremarkable (BUN concentration, 27 mg/dL; creatinine concentration, 0.6 mg/dL) with the exception of mild hyperphosphatemia (8.6 mg/dL), mild hypercalcemia (11.1 mg/dL) attributed to the kitten's age, and mild hypochloremia (115 mmol/L).
At a recheck examination 11 weeks following surgery, the kitten had continued to do well. The kitten's weight was 2.37 kg (5.21 lb), and it had a body condition score of 4 on a scale from 1 to 9. Heart rate, respiratory rate, and rectal temperature were within reference ranges. Findings on recheck abdominal ultrasonographic evaluation were unchanged from findings of previous evaluations, with the exception of mild thickening of the urinary bladder at the level of the cystostomy tubing and scant anechoic fluid and hypoechoic tissue around tubing at the apex of the urinary bladder, presumed to represent postsurgical change rather than mild inflammation. The PCV was 40%, and plasma total protein concentration was 7.1 g/dL. Serum biochemical analysis revealed no abnormalities (BUN concentration, 28 mg/dL; creatinine concentration, 0.7 mg/dL). A urine sample was obtained via cystocentesis for urinalysis and bacteriologic culture; culture of urine yielded Enterococcus faecalis (105 CFUs/mL), which was susceptible to amoxicillin. The kitten was discharged from the hospital, and treatment with amoxicillin (20 mg/kg [9.09 mg/lb], PO, q 12 h) for 4 weeks was prescribed. The owners were given instructions to return the kitten for recheck urinalysis and bacteriologic culture of urine 1 week after finishing the antimicrobial treatment.
At 18 weeks after surgery, the kitten underwent a recheck evaluation. Clinically, the kitten was doing well at home, with no abnormalities reported by the owners. The kitten's weight was 2.6 kg (5.72 lb), and it had a body condition score of 5 on a scale from 1 to 9; findings on physical examination were unremarkable. Serum biochemical variables were within reference ranges. Bacteriologic culture of urine again yielded E faecalis, which was susceptible to amoxicillin. The port was flushed with ampicillin (22 mg/kg) diluted in 6 mL of saline solution (via Huber needle injection into the port), and introduction of the antimicrobial agent into the kidney was confirmed by observation of bubbles in the renal pelvis during ultrasonography. Treatment with amoxicillin (20 mg/kg, PO, q 12 h) for 4 weeks was prescribed. Bacteriologic culture of urine was performed after 2 weeks of antimicrobial treatment and 1 week after discontinuation of treatment; on both occasions, results were negative. Results of bacteriologic culture of urine were negative at last follow-up 16 months after surgery, and the cat was clinically normal.
Angiocath, Becton, Dickinson and Co, Franklin Lakes, NJ.
Isovue 370, Bracco Diagnostics Inc, Princeton, NJ.
SUB, Norfolk Medical, Skokie, Ill.
Berent A, Weisse C, Bagley D. The use of a subcutaneous ureteral bypass device for ureteral obstructions in cats (abstr). Vet Surg 2010;39:E30.
Guide wire, Norfolk Medical, Skokie, Ill.
Red rubber catheter, Bard Medical, Murray Hill, NJ.
Tumil-K, Virbac Corp, Fort Worth, Tex.
2. Nwadike BS, Wilson LP, Stone EA. Use of bilateral temporary nephrostomy catheters for emergency treatment of bilateral ureter transection in a cat. J Am Vet Med Assoc 2000; 217: 1862–1865.
3. Okkens AC, van de Gaag I, Biewenga WJ, et al. Urological complications following ovariohysterectomy in dogs [in Dutch]. Tijdschr Diergeneeskd 1981; 106: 1189–1198.
7. Ruiz de Gopegui R, Espada Y, Majo N. Bilateral hydroureter and hydronephrosis in a nine-year-old female German Shepherd Dog. J Small Anim Pract 1999; 40: 224–226.
8. Adin CA, Herrgesell EJ, Nyland TG, et al. Antegrade pyelography for suspected ureteral obstruction in cats: 11 cases (1995–2001). J Am Vet Med Assoc 2003; 222: 1576–1581.
9. Gookin JL, Stone EA, Spaulding KA, et al. Unilateral nephrectomy in dogs with renal disease: 30 cases (1985–1994). J Am Vet Med Assoc 1996; 208: 2020–2026.
10. Rawlings CA, Bjorling DE, Christie BA. Kidneys. In: Slatter D, ed. Textbook of small animal surgery. 3rd ed. Philadelphia: WB Saunders Co, 2003; 1606–1618.
11. Kyles AE, Stone EA, Gookin J, et al. Diagnosis and surgical management of obstructive ureteral calculi in cats: 11 cases (1993–1996). J Am Vet Med Assoc 1998; 213: 1150–1156.
12. Horowitz C, Berent A, Weisse C, et al. Predictors of outcome for cats with ureteral obstructions after interventional management using ureteral stents or a subcutaneous ureteral bypass device. J Feline Med Surg 2013; 15: 1052–1062.
13. Boyd LM, Langston C, Thompson K, et al. Survival in cats with naturally occurring chronic kidney disease (2000–2002). J Vet Intern Med 2008; 22: 1111–1117.
14. Brourman JD. Successful replacement of an obstructed ureter with an ileal graft in a cat. J Am Vet Med Assoc 2011; 238: 1173–1175.
15. Kulendra E, Kulendra N, Halfacree Z. Management of bilateral ureteral trauma using ureteral stents and subsequent subcutaneous ureteral bypass devices in a cat. J Feline Med Surg 2014; 16: 536–540.
17. Berent AC, Weisse CW, Todd K, et al. Technical and clinical outcomes of ureteral stenting in cats with benign ureteral obstruction: 69 cases (2006–2010). J Am Vet Med Assoc 2014; 244: 559–576.
18. Fink RL, Caridis DT, Chimile R, et al. Renal impairment and its reversibility following variable periods of complete ureteral obstruction. Aust N Z J Surg 1980; 50: 77–83.
20. Von Hendy-Willson VE, Pressler BM. An overview of glomerular filtration rate testing in dogs and cats. Vet J 2011; 188: 156–165.
21. Lennon GM, Thornhill JA, Grainger R, et al. Double pigtail ureteric stent versus percutaneous nephrostomy: effects on stone transit and ureteric motility. Eur Urol 1997; 31: 24–29.
23. Barsanti JA, Blue J, Edmunds J. Urinary tract infection due to indwelling bladder catheters in dogs and cats. J Am Vet Med Assoc 1985; 187: 384–388.
24. Reid G, Denstedt JD, Kang YS, et al. Microbial adhesion and biofilm formation on ureteral stents in vitro and in vivo. J Urol 1992; 148: 1592–1594.
25. Bonkat G, Widmer AF, Rieken M, et al. Microbial biofilm formation and catheter-associated bacteriuria in patients with supra-pubic catheterization. World J Urol 2013; 31: 565–571.