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Acute urinary retention secondary to bladder outlet obstruction — MSRA MCQ

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HardLUTSAcute urinary retention secondary to bladder outlet obstructionMSRA

A 70-year-old man presents with a 12-hour inability to pass urine and increasing suprapubic pain. He has had 10 months of hesitancy, weak stream, intermittency and nocturia but has not sought previous treatment. He started an over-the-counter night-time cold remedy containing chlorphenamine 2 days ago. He is afebrile and haemodynamically stable. His bladder is palpable and a bladder scan shows 850 mL post-void residual volume. Urine dipstick is negative for blood, leucocytes and nitrites. Serum creatinine is unchanged from baseline. Digital rectal examination shows a smooth moderately enlarged prostate. He has no history of postural hypotension, falls or cataract surgery. What is the most appropriate immediate management plan?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: C — Insert a urethral catheter and start tamsulosin before a planned trial without catheter

Explanation lettering: D = shown as C · E = shown as D · C = shown as E

This is acute urinary retention: painful inability to void, a palpable bladder and an 850 mL residual volume require immediate bladder drainage. The likely precipitant is chlorphenamine, whose anticholinergic effect may worsen pre-existing bladder outlet obstruction from benign prostatic enlargement, but withdrawing it does not remove the need for urgent catheterisation. NICE recommends immediate catheterisation for acute retention and an alpha blocker before catheter removal. Tamsulosin is therefore appropriate while the catheter is in situ, to improve the likelihood of a successful trial without catheter. There is no stated contraindication to alpha blockade in this case. A is incomplete because catheterisation alone omits the recommended alpha blocker before trial without catheter. B delays decompression of symptomatic acute retention. C is inappropriate for the immediate phase: finasteride may be relevant later for progression risk in men with an enlarged prostate, but its onset is too slow to facilitate trial without catheter. E incorrectly prioritises surgery over immediate decompression; surgery may be considered subsequently if retention recurs or medical management fails.

Reference: NICE CG97: Lower urinary tract symptoms in men: management — Treating urinary retention (2010; page checked August 2026) — https://www.nice.org.uk/guidance/cg97/chapter/recommendations NICE CG97: Lower urinary tract symptoms in men: management — Treating urinary retention (2010; page checked August 2026) — https://www.nice.org.uk/guidance/cg97/chapter/recommendations