February's Case of the Month

Ectopic Ureters and Renal Dystrophy in A Mixed Breed Canine

Shadawn Salmond-Jimenez DVM

Patient Information:

Age: 1.5 years

Gender: Spayed Female

Species: Canine

History:

Severe urinary incontinence and polyuria and polydipsia since spay at adoption (previous history unknown), at least 2 months duration. Patient is now mildly azotemic with an elevated SDMA (Crea 2.0, BUN 33, SDMA 17).

Image Interpretation:

The left kidney measures 6.5 cm length with poor cortical medullary distinction. The pelvis is mildly widened measuring 5.3 mm thick in transverse. The right kidney measures 4.5 cm length with poor cortical medullary distinction. The pelvis measures approximately 3.2 mm wide. The urinary bladder contains normal anechoic urine. No atypical mural thickening, masses, or intraluminal calculi are identified. Best seen on the transverse images, a moderately dilated ureter courses through the dorsal wall of the urinary bladder.

Diagnosis and Sonographic Analysis:

The significant remodeling to both kidneys with pyelectasia is most consistent with underlying congenital/developmental renal dysplasia. An intramural ectopic left ureter is also suspected in this patient.

Case outcome:

Owner wanted to pursue surgical options, understanding the long term prognostic complication of concurrent renal dysplasia in this patient.

Brief Overview of Ectopic Ureters and Renal Dystrophy:

Ectopic ureter (EU) is a congenital anomaly of the urinary system where the ureteral orifice is inappropriately positioned caudal to the urinary bladder. This is the most common cause of urinary incontinence in juvenile female dogs, accounting for over 50% of cases in one study.

Other associated urinary conditions such as urinary tract infection (UTI) (64%), renal agenesis/dysplasia (5%), hydroureter (34–50%) or hydronephrosis (15–27%), short urethras (21%), persistent paramesonephric remnants/vaginal septum/dual vagina (93%), hormonal imbalances and ureterocoeles have all been reported concurrently. 

EUs tunnel either intramurally or extramurally, with over 95% in dogs reported to be intramural. The typical intramural EU will enter the distal bladder neck in a relatively normal position but fail to open into the bladder lumen, traversing the urethra to the level of the prostate, vestibule or vagina in the submucosal tissue, where it terminates.

Laser ablation of ectopic ureters is an outpatient procedure and met with similar, if not better, outcomes than those reported with traditional surgery.

Allyson Berent, DVM, DACVIM 
The Animal Medical Center
New York, NY, USA 

A transverse view of the left dilated ureter (green arrow) within the dorsal bladder wall. The urinary bladder is

seen directly ventral to the round colon.

A sagittal view of a normal canine left kidney

The left kidney of this patient is most consistent with renal dystrophy. Poor cortical medullary distinction is present. Similar changes were also seen in the right kidney.

A special thanks to the staff at Diamond Veterinary Hospital for this interesting case. A special thanks to Dr. Matthew Paek, VMD, MS, DACVR at Synergy VIP for his interpretation of the case.