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Nocturnal polyuria associated with heart failure and diuretic-treated fluid overload — MSRA MCQ

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HardUrologyNocturnal polyuria associated with heart failure and diuretic-treated fluid overloadMSRA

A 76-year-old man reports waking three to four times nightly to pass urine, despite limiting evening fluids and taking tamsulosin for stable voiding LUTS. A 3-day frequency-volume chart shows nocturnal urine production of 1.1 L, representing 42% of his 24-hour urine volume. Daytime frequency is normal and there is no urgency incontinence. He has heart failure with reduced ejection fraction and takes furosemide 40 mg each morning, ramipril and bisoprolol. He has mild bilateral ankle oedema but no acute breathlessness. eGFR is 58 mL/min/1.73 m² and serum sodium is 139 mmol/L. Which is the most appropriate next management step?

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

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Correct answer: E — Review fluid-overload management and consider late-afternoon loop-diuretic dosing rather than desmopressin

Explanation lettering: D = shown as A · A = shown as B · B = shown as D

The diary establishes nocturnal polyuria rather than reduced bladder capacity or overactive bladder: nocturnal urine volume is disproportionately high, while daytime frequency and urgency are absent. However, this is not idiopathic nocturnal polyuria. Heart failure with residual peripheral oedema and a requirement for loop diuretic treatment provides a likely fluid-overload mechanism. NICE advises considering a late-afternoon loop diuretic for nocturnal polyuria. In contrast, desmopressin should be considered only after other medical causes have been excluded and other treatments have failed. The UK SmPC for Noqdirna specifically contraindicates desmopressin where cardiac insufficiency or another fluid-overload condition requires diuretic treatment. His preserved sodium and eGFR above 50 mL/min do not remove that contraindication. A is attractive because sodium monitoring at 3 days is a NICE requirement, but desmopressin is unsuitable in this patient. B is also incorrect: 25 micrograms is the female dose and does not overcome the contraindication. C would be appropriate for persistent storage symptoms, particularly urgency or urgency incontinence, which are absent. D may be appropriate in men with enlarged prostates at risk of progression, but his presentation is driven by nocturnal polyuria rather than progressive outlet obstruction.

Reference: NICE CG97: Lower urinary tract symptoms in men: management — Recommendations (2010; last reviewed December 2024) — https://www.nice.org.uk/guidance/cg97/chapter/recommendations Noqdirna 50 microgram oral lyophilisate — Summary of Product Characteristics (15 June 2026) — https://www.medicines.org.uk/emc/product/4372/smpc