ECTOPIC URETER

Ectopic ureter
Definition :
The ureteric orifice is situated below the normal anatomical insertion on the trigone of the bladder.

Pathogenesis
The ureteric bud arises from an abnormal position on the mesonephric duct during embryological development. Females are affected more than males (female:male ratio 3:1). 80% are associated with a duplicated collecting system (which predominantly affects females). A duplex kidney has an upper pole and a lower pole, each with its own renal pelvis and ureter. The two ureters may join to form a single ureter, or they may pass down individually to the bladder (complete duplication). In this case, the upper pole ureter always opens onto the bladder below and medial to the lower pole ureter (Weigertâ? Meyer rule), predisposing to ectopic placement of the ureteric orifice.

Sites of ectopic ureters
- Females: bladder neck, urethra, vagina.
- Males: posterior urethra, seminal vesicles, ejaculatory duct, vas deferens, epididymis, bladder neck.

Presentation
Acute or recurrent UTI is common in both sexes. Obstruction of the ectopic ureter can lead to hydronephrosis and hydroureter, which may present as an abdominal mass.
- Females: when the ureteric opening is below the urethral sphincter, girls present with persistent vaginal discharge or incontinence, despite successful toilet training.
- Males: the ureter is always sited above the external urethral sphincter, so boys do not develop incontinence. UTIs may trigger epididymitis.

Investigation of urinary tract
- USS demonstrates ureteric duplication, dilatation, and hydronephrosis.
- IVU identifies duplex systems and gives information on renal segment function.
- Micturating cystourethrography (MCUG) assesses reflux in lower pole ureters.
- Cystourethroscopy can directly identify a ureteric opening in the urethra.
Isotope renogram (99mTc-DMSA) assesses renal function to help plan surgery

Treatment
An ectopic ureter is often associated with a poorly functioning renal upper pole or single-system kidney. In such cases, surgery consists of open or laparoscopic heminephrectomy or total nephrectomy with excision of the associated ureter. Where some function is retained in a single-system kidney, the distal ureter can be resected and reimplanted into the bladder.