Posterior urethral valves — newborn management structured clinical encounter

Task 1 — Risk-stratify and recognise the diagnosis (4 minutes)

Read the antenatal data and the newborn examination. State the leading diagnosis and the risk band, and justify your reasoning from the APD values, the bladder, the laterality, the sex and the oligohydramnios. The expected answer is posterior urethral valves in the critical to high-risk band: the male sex, bilateral APD well above 10 mm, the thick-walled distended bladder, and the oligohydramnios together make posterior urethral valves the leading diagnosis until proven otherwise. [3] [7]

Task 2 — Immediate management bundle (5 minutes)

Outline your actions in the first 72 hours: ultrasound timing, catheterisation, prophylaxis, baseline bloods, and specialist referral. The expected bundle is a renal ultrasound within 48 to 72 hours (or sooner given the palpable bladder); a urethral catheter to decompress the bladder; a prophylactic antibiotic (confirm agent and dose locally) pending exclusion of obstruction and reflux; baseline creatinine and electrolytes; and urgent paediatric urology referral for a voiding cystourethrogram to confirm the dilated posterior urethra and valve, then cystoscopic valve ablation. Maintain hydration and perfusion. [3] [6]

Task 3 — Imaging interpretation and functional testing (4 minutes)

The voiding cystourethrogram confirms a dilated posterior urethra with an obstructing valve. Explain what further functional imaging may be needed and why, and what the ultrasound would show in bilateral dysplasia. The expected answer is MAG3 renography for differential renal function once the infant is stable, and DMSA to map cortical damage and confirm dysplasia if the ultrasound shows echogenic, small kidneys with loss of corticomedullary differentiation. The functional imaging quantifies how much renal reserve remains and guides the long-term surveillance intensity. [7] [1]

Task 4 — Long-term surveillance and family counselling (5 minutes)

Design the long-term follow-up and counsel the parents. Address their distance from the centre and their question about their son's kidneys. Acknowledge that even after successful valve ablation a substantial proportion of these boys progress to chronic kidney disease or end-stage renal disease, as confirmed by a recent systematic review and meta-analysis. Long-term surveillance includes blood pressure, growth, serial creatinine and eGFR, urinalysis for proteinuria, serial ultrasound, and bladder-function assessment, with combined nephrology and urology follow-up and a transition plan to adult renal care. For a family two hours from the centre, build the plan around telehealth reviews, a confirmed local pathway for urgent review if fever occurs, and a clear written safety-net that a urinary tract infection in this baby is not simple cystitis. [7] [8]

Task 5 — Closing the loop (2 minutes)

Summarise the two discharge questions that must be answered for any infant with an antenatal renal finding, and name the written artefacts that complete the disposition. The first question is when the postnatal ultrasound is booked and whether the timing is matched to the risk band. The second is whether the family has a written fever safety-net. The discharge record and the family's handheld record must name the follow-up owner, the surveillance plan, and the safety-net so the plan survives shift, site and clinician changes. [3]