Ureterocele

A ureterocele is a cystic dilation of the terminal intravesical ureter. It is caused by a pinpoint stenotic ureteral orifice and a congenital weakness of the muscular wall of the distal ureter. The ureter balloons within the bladder, urethra or both.

Incidence is about 1 in 4,000 children (autopsy), with a female predominance of 4 to 7:1. About 10 percent are bilateral.

Types:

• Intravesical (simple): wholly within the bladder, usually in adults, and associated with single systems.
• Ectopic: some part extends to the bladder neck or urethra. It occurs mostly in children and is related to the upper pole of a duplex kidney in 80 percent.

A ureterocele associated with the upper pole moiety of a duplex system leads to obstruction with a dysplastic hydronephrotic upper pole. It also causes reflux into the lower pole and compression of the bladder neck or the contralateral ureteric orifice.

Consequences: recurrent urinary tract infection, urosepsis, stone formation, bladder outflow obstruction, and renal damage.

• Antenatal hydronephrosis with a thin walled cystic structure in the bladder (found on the third trimester ultrasound), the most common presentation now.
• Febrile urinary tract infection or urosepsis in infants (the most frequent postnatal presentation), with flank pain, failure to thrive, haematuria and abdominal mass.
• In girls, a prolapsing ureterocele through the urethra presents as a protruding interlabial cystic mass, with urinary retention.
• Voiding dysfunction, urinary retention, and incontinence (from sphincter damage in ectopic ureterocele of the urethra).
• Adults: flank pain, stones, recurrent infection, haematuria, and incidental findings.
• Hypertension, rarely, if there is renal dysplasia.

• Ultrasound (renal and bladder): a thin walled cystic structure within the bladder (the "cobra head"), a duplex kidney with a hydronephrotic, thinned upper pole and dilated ureter, and bladder outflow assessment; ureterocele size, wall thickness and associated hydroureter.
• Voiding cystourethrogram: filling defect (cobra head, or a negative shadow) and vesicoureteral reflux into the lower pole or the contralateral ureter in 50 percent; a prolapsing ureterocele can be seen as everted.
• Renal scintigraphy (MAG3 or DMSA) for split renal function and obstruction; MRI urography for anatomy where unclear.
• Cystoscopy for confirmation and treatment.
• Urine culture; renal function.

Management is individualised according to presentation, type, renal function, symptoms and age.

• Prophylactic antibiotics from diagnosis prevent infection until definitive treatment. Use amoxicillin 10 to 15 mg/kg once daily under 2 months, then trimethoprim 2 mg/kg once daily at night or nitrofurantoin 1 to 2 mg/kg at night.
• Infected ureterocele or sepsis: intravenous antibiotics (ampicillin 50 mg/kg every 6 hours plus gentamicin 5 to 7 mg/kg once daily, or ceftriaxone 50 to 75 mg/kg daily) and early decompression by endoscopic puncture.
• Endoscopic decompression (transurethral incision or puncture) is the first line treatment in most infants and children with ectopic or obstructive ureterocele and sepsis, or with bladder outflow obstruction. A laser or electrode incises the ureterocele at its lowest point, with a low pressure bladder, which collapses it.
• Success for decompression is about 80 to 90 percent in intravesical types. It is lower in ectopic types, where 30 to 50 percent need further surgery because of de novo reflux into the ureterocele, which occurs in up to 50 percent after incision.
• Upper pole partial nephrectomy (or heminephrectomy) and ureterectomy for a poorly functioning upper moiety (function below 10 percent) or when the lower pole is normal. Remove the dilated ureter to the pelvic brim. Alternatively drain by pyeloureterostomy (upper-to-lower pole ureter anastomosis). Open or laparoscopic.
• Total reconstruction (ureterocele excision, bladder floor reconstruction and common sheath ureteral reimplantation) for large ureteroceles, reflux, or failed endoscopic therapy, usually at 12 to 18 months of age or older. Add trigone and bladder neck reconstruction as needed.
• Simple intravesical ureterocele in adults: endoscopic incision or unroofing if symptomatic (stones, obstruction, infection), with stone removal. Asymptomatic ureteroceles can be observed.
• Follow up with renal ultrasound at 3 to 6 months, voiding cystourethrogram for reflux, and periodic renal function and DMSA. Continue prophylaxis until reflux is resolved.
• Prognosis: depends on renal damage; recurrent infection and need for secondary procedures are common.