A newborn male infant has a distended abdomen, palpable bilateral flank masses, a constantly dribbling urine stream, and a palpably distended bladder. Ultrasound shows bilateral hydronephrosis and a thick-walled bladder. Which investigation will confirm the diagnosis?

• A Plain radiograph of the abdomen
• B Renal dynamic scintigraphy with DTPA
• C Urethrocystoscopy under anaesthesia
• D Micturating cystourethrogram showing a dilated posterior urethra ✓

Explanation

The presentation is classic for posterior urethral valves, the commonest cause of lower urinary tract obstruction in male infants. The diagnostic study is a micturating (voiding) cystourethrogram, which shows a dilated posterior urethra with a sharp transition at the level of the valves, along with a trabeculated bladder and vesicoureteric reflux. Cystoscopy confirms the valves but is therapeutic rather than the initial confirmatory investigation.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.