Congenital anterior urethral diverticulum: A case report.

Sir,

Congenital anterior urethral diverticulum (AUD) is a rare cause of obstructive uropathy in children. Children usually present with difficulty in micturition, followed by dribbling of urine. Diverticulum needs treatment to alleviate symptoms and to preserve renal function.

We treated a 12-year-old boy with AUD treated successfully by excision of the diverticulum and primary repair of the urethra. The child presented with the complaints of straining at micturition, swelling of the penis during micturition, followed by dribbling of urine and disappearance of the swelling since his early childhood. Micturating cystourethrogram (MCU) showed a large AUD [Figure 1]. There was no vesico-ureteral reflux. Ultrasonography of the upper tract was normal.

Figure 1

Micturating cystourethrogram showing a large anterior urethral diverticulum

A circumcoronal incision was made on ventral half of the penis and penile skin was degloved, and the diverticulum was dissected all round and was excised flush with the urethra. Urethra was repaired in a single layer by extra-mucosal suture by 6-0 vicryl over a 6 Fr Foley catheter. Cather was removed on 5th postoperative day. Patient passed urine normally after that. He was followed-up for 6 months with a satisfactory result.

Cause and effect relationship between anterior urethral valve and AUD has been widely debated. Two possible mechanism of urethral obstruction due to AUD with or without a valve has been described. During voiding, obstruction due to anterior urethral valve distends the diverticulum just proximal to the valve which in turn undermines and compresses the proximal urethra, resulting in increased obstruction.[12] Others believed that the diverticulum is the primary lesion and that as the diverticulum fills with urine during voiding its distal lip is forced against the roof of the urethra, obstructing the outflow of urine.[3] Cases may be diagnosed in the antenatal period or in infancy. Children beyond infancy usually present with difficulty in micturition, swelling of the ventral urethra, poor stream and dribbling of urine, or urinary tract infection. A careful history reveals that the child never had a good urinary flow since birth, and a tell-tale sign is a cystic swelling at the ventral urethra. All these symptoms and signs were present in our case.

Diagnosis is usually made by an MCU or a retrograde urethrogram, but an MCU has the advantage of demonstrating bladder changes and vesico-ureteral reflux. Small AUD can be treated by endoscopic cutting or deroofing if the diverticulum has a distal lip that can be hooked and divided by a resectoscope knife or hook.[4] Others prefer open diverticulectomy and repair. For a large diverticulum, open diverticulectomy and urethroplasty is the treatment of choice.