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Bilateral Ureterolithiasis and Hydronephrosis in a 10-Year-Old Female Spayed DLH Cat: Our Case Of the Month February 2018

Patient Information

10 Years
Female, Spayed


Exam Findings


Left kidney ureterolith.
Right kidney ureterolith.

"OUCH!" Acute pain on palpation…. who would have thought there would be not one, but TWO ureteroliths causing pain in this DLH feline patient. Normal ureters are generally NOT visible on a scan, but acute pain in the region of the kidneys should clue you in to pay particular attention to the kidney region, including use of not just the micro convex probe but also the linear probe to highlight and create those “artistic” views. When you find pathology, such as a dilated ureter, FOLLOW it and see where it goes and what may be hiding there…. Our 17-point SDEP Abdomen protocol teaches you how to do this routinely with EVERY patient, and every potential pathology. Many thanks to Dr. Candace Remcho of West Hills Animal Hospital in Corvallis, Oregon for the proficient case management of this patient, as well as the comprehensive interpretation of this case by the newest addition to the Sonopath Team of Specialists, Dr. R.McKenzie “Mac” Daniel, DVM, DABVP (Canine and Feline). Also, a loud shout out to Heidi Putnam, clinical SDEP sonographer of Animal Sounds NW Veterinary Mobile Ultrasound for the exemplary imaging. 


The patient presented for pain in the area of the kidneys, dehydration, and anorexia with increased renal values. The patient initially improved after treatment with I.V. fluids, but the symptoms returned 5 days later. Cerenia, SQ fluids, and buprenorphine were added to the treatment plan. Preliminary blood chemistry revealed BUN 128, creat. 7.6 which improved to a BUN of 29 and a creat. of 2.2; all other parameters were WNL.

Image Interpretation

The left kidney was small in size with mildly irregular margination. Moderate hydronephrosis was present with obliteration of the renal medulla parenchyma. Indistinct corticomedullary differentiation was present between the cortex and remaining medulla. The hydronephrosis in the left kidney measured 1.6 x 0.8 cm and extended into the proximal left ureter. Left ureter dilation measured 0.3 cm. A focal, echogenic ureterolith with acoustic shadowing was present within the lumen of the left ureter and measured 0.3 cm in diameter and was located approximately 0.5 cm from the renal pelvis. The left kidney measured 2.3 cm in length. The right kidney presented normal in size and margination with indistinct corticomedullary distinction and emerging mild hydronephrosis was present. Mild obliteration of the right renal medulla parenchyma was noted. The hydronephrosis in the right kidney measured 0.9 x 0.8 cm and extended into the right ureter. Right ureter dilation measured 0.3 cm. A focal, echogenic ureterolith with distal acoustic shadowing was located approximately 2.0 cm from the right kidney renal pelvis. 


Bilateral ureterolithiasis present in the right and left ureters with secondary proximal ureter dilation. This is consistent with partial to complete obstruction. Marked hydronephrosis with loss of normal renal medulla parenchyma in the left kidney and merging to mild hydronephrosis with mild loss of normal renal medulla parenchyma of the right kidney. Focal nephrolithiasis was present within the dilated renal pelvis and medulla of the right kidney.


The bilateral ureteroliths are likely causing partial to complete obstruction of the right and left ureter with hydronephrosis in the right and left kidney. Smaller left kidney size with marked hydronephrosis suggests more chronic disease in the left kidney. The functionality of the left kidney is highly questionable. The pain exhibited by the patient is likely associated with the ureterolithiasis and development of hydronephrosis. Treatment options would likely be centered around preserving functionality of the right kidney. Referral in this case for possible surgical options such as ureterolith removal or possible stent placement is recommended. Placement of a subcutaneous ureteral bypass device (SUB) is also an option in this case. If referral is not an option then conservative treatment may include continued IV fluids, pain medications and an Alpha blocker such as Prazosin to try to get the ureteroliths to move. This may or may not be possible. Therefore, guarded prognosis is warranted in this case. Systemic blood pressure may also be considered due to the degree of renal disease.Unfortunately, due to quality of life concerns and a poor prognosis the patient was humanely euthanized.


Normal urinary bladder with anechoic urine in lumen. No calculi are present.
A ureterolith is present in the proximal left ureter causing partial to complete obstruction. Secondary hydronephrosis is present in the left kidney with loss of renal parenchyma.
Power Doppler on the hydronephrotic left kidney suggestive of decreased vascularity and renal volume.
A ureterolith is present in the proximal right ureter causing partial to complete obstruction. Secondary hydronephrosis is present in the right kidney with loss of renal parenchyma.
Distinct visualization of the ureterolith in the right ureter. Power Doppler is used to show lack of blood flow within the dilated right ureter, distinguishing the dilated ureter from a blood vessel.