A4-year-old neutered male domestic shorthair weighing 3.0 kg (6.6 lb) was admitted to the hospital for apparent dysphagia. The cat was quiet, alert, and responsive and had a body condition score of 1/5. Heart rate was 200 beats/min, rectal temperature was 37.7°C (100.5°F), and respiratory rate was 24 breaths/min. A CBC and serum biochemical analyses revealed Hct of 26.3% (reference range, 30% to 45%), total plasma protein concentration of 8.2 g/dL (reference range, 6.0 to 8.0 g/dL), BUN concentration of 94 mg/dL (reference range, 15 to 35 mg/dL), creatinine concentration of 6.1 mg/dL (reference range, 0.9 to 2.3 mg/dL), phosphorus concentration of 9.6 mg/dL (reference range, 2.6 to 8.8 mg/dL), and globulin concentration of 4.2 g/dL (reference range, 2.3 to 3.8 g/dL). Urinalysis revealed urine specific gravity of 1.012 with 0 to 2 WBCs/hpf, 10 to 14 RBCs/hpf, and 5 to 9 epithelial cells/hpf. Aerobic bacteriologic culture of urine did not yield bacterial growth.
The cat was administered lactated Ringer's solution (100 mL/kg [45.5 mL/lb]/d, IV) and famotidine (0.5 mg/kg [0.23 mg/lb], IV, q 24 h). Abdominal radiography revealed multiple ureteroliths in the right ureter ventral to the fifth lumbar vertebra. The right renal pelvis contained 2 moderate-sized nephroliths and 1 small nephrolith (Figure 1). Severe bilateral hydronephrosis and right hydroureter were found via ultrasonography. Contrast medium (barium) was administered PO, and radiography did not reveal any abnormalities related to the apparent dysphagia. Excretory urography confirmed the diagnoses of right hydroureter, hydronephrosis, and ureteroliths and revealed that the left kidney did not contain concentrated contrast medium, which suggested that it was nonfunctional. It was noted that spontaneous movement of ureteroliths had occurred between the time of the survey lateral projection and the first radiograph made as part of the excretory urogram 3 hours and 45 minutes later. Serum BUN and creatinine concentrations decreased to 47 and 2.3 mg/dL, respectively, by day 5.
Surgery to remove the left kidney, right ureteroliths, and right nephroliths was scheduled 5 days after initial abdominal radiographs were obtained. Preoperative radiography revealed 3 moderate-sized nephroliths in the right renal pelvis, as opposed to 2 moderate-sized and 1 small nephroliths detected 5 days earlier (Figures 1 and 2). In the region of the obstruction of the ureter, there were fewer ureteroliths. This indicated that 1 of the ureteroliths had moved retrograde approximately 4 centimeters into the right renal pelvis. Additionally, sandlike material had moved retrograde. The left kidney was removed, and 6 ureteroliths were removed from the right ureter via ureterotomy in the proximal dilated portion of the ureter. A 3.5-F urinary catheter was inserted proximally into the renal pelvis, and some of the nephroliths were flushed out through the ureterotomy incision. Despite attempts to locate and remove all of the uroliths, some uroliths remained after surgery. Postoperative radiography revealed 1 urolith in the right renal pelvis, 1 in the distal right ureter approximately at the level of L6, and 1 in the proximal portion of the right ureter. Radiography was repeated 2 days later. One urolith was found in the renal pelvis, and both of the ureteroliths were present in the distal ureter at the level of L6. The BUN and creatinine concentrations were 44 and 2.6 mg/dL, respectively. A second surgery to remove the remaining uroliths was scheduled in 1 month.
One month later, preoperative radiography revealed 2 uroliths in the right renal pelvis and 1 ureterolith in the distal portion of the right ureter at the level of L6. One of the ureteroliths had moved retrograde approximately 4 centimeters into the right renal pelvis (Figure 3). Surgery was performed the same day. At the time of surgery, the distal ureterolith was also suspected to have moved retrograde into the right renal pelvis, such that 3 uroliths were present in the right renal pelvis. This suspicion was based on the fact that the distal ureterolith in the right ureter was palpated in the distal portion of the ureter during the initial stages of surgery, and vascular ties were placed around the ureter to attempt to maintain its position; however, when the surgeon was ready to remove the ureterolith, the ureterolith was no longer identifiable in that location. After an extensive attempt to relocate the ureterolith, the surgeon decided that it had likely moved proximally into the right renal pelvis. A proximal ureterotomy was performed to remove the uroliths in the right renal pelvis. Two uroliths were successfully removed from the right renal pelvis, but a third urolith could not be identified. Postoperative radiography revealed that the urolith was again in the distal portion of the ureter. Given the size of the urolith, the surgeon was convinced that it had moved into the renal pelvis during surgery, then back into the ureter after surgery; however, it was not possible to definitively document that movement without intraoperative imaging. The cat recovered from surgery without complications and was discharged with a serum BUN con centration of 33 mg/dL and a creatinine concentration of 2.3 mg/dL.
The cat was reevaluated 24 months after surgery because serum creatinine concentration had increased from a range of 2.1 to 2.2 mg/dL since surgery to 2.4 mg/dL and the BUN concentration was 38 mg/dL. The cat was clinically normal. Abdominal radiography and ultrasonography revealed that there was a right ureterolith in a similar location to the postoperative location 2 years prior. The right kidney was small and had dilatation of the pelvis and proximal portion of the ureter. Ureterotomy was performed, and the ureterolith was successfully removed. Postoperative radiography confirmed urolith removal. The cat was discharged 4 days after surgery with a BUN concentration of 30 mg/dL and a creatinine concentration of 2.1 mg/dL.
During the period from 1992 to 2002, retrograde movement of ureteroliths was detected in our hospital in 4 additional cats and 2 dogs by use of serial abdominal radiography (n = 4), ultrasonography (1), fluoroscopy (1), or a combination of ultrasonography and fluoroscopy (1). The ureteroliths ranged in diameter from 1 to 6 millimeters. Two cats and 1 dog had 2 ureteroliths that moved retrograde, and 1 dog and 3 cats had only 1 ureterolith that moved retrograde. The distance that the ureteroliths moved retrograde was approximately 2 centimeters in both dogs and 4 cats. In 1 cat, 2 ureteroliths moved retrograde, with the most distal ureterolith moving approximately 4 centimeters back into the renal pelvis. In 2 dogs and 1 cat, the uroliths were initially detected in the renal pelvis, subsequently passed into the ureter, and then moved retrograde into the renal pelvis. In both dogs and 1 cat, there was a marked increase of serum creatinine concentrations while the urolith was in the ureter and the serum creatinine concentration decreased when the urolith moved retrograde into the renal pelvis.
Shock wave lithotripsy
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