Minimal renal pelvis dilation in cats diagnosed with benign ureteral obstruction by antegrade pyelography: a retrospective study of 82 cases (2012–2018)

Abstract

Objectives The aim of the study was to describe renal pelvis (RP) and ureteral ultrasonographic measurements in a population of cats with confirmed benign ureteral obstruction (UO) by antegrade pyelography. The secondary objective was to further describe clinical findings associated with minimally dilated obstructed kidneys in an attempt to better understand its occurrence. Methods Retrospective case series of cats diagnosed with benign UO were confirmed by antegrade pyelography. Medical records were reviewed and signalment, diagnostic imaging results, serum creatinine (SCr) concentration and urine culture results were recorded. Each obstructed kidney was categorized into two groups: group 1 included all RP measurements ⩽4 mm and group 2 included all RP measurements >4 mm. Results A total of 82 cats with 114 obstructed ureters met the inclusion criteria. Fifty (61%) cats had a unilateral UO and 32 (39%) had a bilateral UO. Thirty (26%) kidneys were included in group 1 while 84 (74%) were included in group 2. Nine (8%) kidneys had an RP dilation ⩽2 mm. Median RP and ureteral diameters were 6.6 mm (range 1.1–37.0 mm) and 3.2 mm (range 0.0–11.0 mm), respectively. RP size correlated positively with ureteral diameter in the study population ( P <0.0001), but not in group 1 when analyzed separately ( P = 0.47). UO was secondary to stones in 80 (70%) ureters. Seventeen (21%) cats had a positive urine culture. At admission, 79 (96%) cats were azotemic with a median preoperative SCr concentration of 444 µmol/l (range 108–1326 μmol/l). The mean (95% confidence interval [CI]) preoperative SCr concentration was significantly higher in group 1 (762 µmol/l [498–1165 μmol/l]) than in group 2 (409 µmol/l [333–502 μmol/l]). RP size in the two groups correlated negatively with preoperative SCr concentration ( P = 0.0002). Conclusions and relevance Feline UO may be associated with minimal RP dilation and the severity of RP and ureteral dilation can be highly variable. Absence of significant RP dilation does not rule out UO in cats.

Subcutaneous ureteral bypass device placement in 81 cats with benign ureteral obstruction (2013‐2018)

“…[1][2][3][4][5][6][7][8][9][10] Obstructive calcium oxalate ureterolithiasis is the most frequent cause of BUO in cats. [8][9][10][11] Cats with BUO often have chronic kidney disease (CKD) and are azotemic at the time of presentation. 2,3,5,8,9,[12][13][14] There are various options available for the treatment of BUO.…”

“…[8][9][10][11] Cats with BUO often have chronic kidney disease (CKD) and are azotemic at the time of presentation. 2,3,5,8,9,[12][13][14] There are various options available for the treatment of BUO.…”

“…18 Subcutaneous ureteral bypass (SUB) device placement is an effective treatment option for BUO in cats. [6][7][8][9][10]12,14,20 A retrospective study of SUB device placement in 174 ureters of 134 cats demonstrates the advantages of SUB placement as a treatment of BUO in cats compared to other options with a 6% postoperative death rate and fewer long-term complications compared to other surgical options. 8 The aims of the study were to determine outcome and complications in a large cohort of cats undergoing SUB device placement had BUO at our hospital.…”

“…Benign ureteral obstruction (BUO) occurs in cats and can be secondary to ureterolithiasis, ureteral strictures, infection, dried solidified blood stones, retroperitoneal fibrosis after renal transplant, or iatrogenic ureteral ligation. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 Obstructive calcium oxalate ureterolithiasis is the most frequent cause of BUO in cats. 8 , 9 , 10 , 11 Cats with BUO often have chronic kidney disease (CKD) and are azotemic at the time of presentation.…”

“… 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 Obstructive calcium oxalate ureterolithiasis is the most frequent cause of BUO in cats. 8 , 9 , 10 , 11 Cats with BUO often have chronic kidney disease (CKD) and are azotemic at the time of presentation. 2 , 3 , 5 , 8 , 9 , 12 , 13 , 14 …”