Paediatric urology: posterior urethral valves: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Paediatric urology: posterior urethral valves

Sample item

A 2-month-old boy has a poor urinary stream and a palpable bladder. Ultrasound shows bilateral hydroureteronephrosis and a thick-walled bladder. Which investigation confirms the diagnosis?

AMAG3 diuretic renogramBMicturating cystourethrogramCIntravenous urogramDDMSA renal scan

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Micturating cystourethrogram

Posterior urethral valves are the commonest cause of congenital bladder outlet obstruction in boys and cause bilateral hydronephrosis and a trabeculated bladder. A micturating cystourethrogram shows a dilated, elongated posterior urethra with an abrupt change in calibre at the valves. Initial treatment is catheter drainage followed by endoscopic valve ablation.

Option by option

A. MAG3 diuretic renogram
MAG3 renography evaluates drainage at the pelviureteric junction, not urethral valves.
B. Micturating cystourethrogram (correct)
The study shows the dilated posterior urethra and the obstructing valves.
C. Intravenous urogram
Intravenous urography is poor in neonates and does not show the urethra.
D. DMSA renal scan
DMSA scintigraphy assesses cortical scarring and differential function, not the obstruction site.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is B, Micturating cystourethrogram. Posterior urethral valves are the commonest cause of congenital bladder outlet obstruction in boys and cause bilateral hydronephrosis and a trabeculated bladder.

Why is "MAG3 diuretic renogram" not the answer?

MAG3 renography evaluates drainage at the pelviureteric junction, not urethral valves.

Why is "Intravenous urogram" not the answer?

Intravenous urography is poor in neonates and does not show the urethra.

Why is "DMSA renal scan" not the answer?

DMSA scintigraphy assesses cortical scarring and differential function, not the obstruction site.

What concept does this question test?

It tests Paediatric urology: posterior urethral valves in General Surgery. A micturating cystourethrogram shows a dilated, elongated posterior urethra with an abrupt change in calibre at the valves. Initial treatment is catheter drainage followed by endoscopic valve ablation.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Paediatric urology: posterior urethral valves?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.