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Recurrent uncomplicated lower urinary tract infection — MSRA MCQ

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HardUrinary Tract InfectionsRecurrent uncomplicated lower urinary tract infectionMSRA

A 29-year-old non-pregnant woman requests prevention of recurrent urinary tract infection (UTI). She has had four culture-confirmed Escherichia coli lower UTIs in the past 10 months. Each episode caused dysuria, frequency and suprapubic discomfort without fever, loin pain, vomiting or visible haematuria. Each occurred within 24 hours of sexual intercourse. She is currently asymptomatic. She has stopped using spermicidal contraception, avoids delayed voiding and has increased her fluid intake, but episodes continue. She has regular menstrual periods and no vaginal dryness or dyspareunia. There is no urinary tract abnormality, diabetes, renal stone history or catheter use. Her eGFR is 76 mL/minute/1.73 m². The most recent three isolates were susceptible to nitrofurantoin and resistant to trimethoprim and cefalexin. She wishes to minimise total antibiotic exposure. What is the most appropriate management now?

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

Reveal the answer and explanation

Correct answer: A — Provide nitrofurantoin 100 mg as a single dose after sexual intercourse, with review within 6 months

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

She meets the definition of recurrent UTI and has a consistent identifiable trigger: sexual intercourse. She is currently free of infection, behavioural measures have not been effective, and vaginal oestrogen is not appropriate because she is premenopausal without genitourinary symptoms of menopause. NICE therefore supports a trial of single-dose antibiotic prophylaxis when exposed to the trigger. Nitrofurantoin 100 mg as a single dose is an appropriate first-choice prophylactic regimen because her eGFR is above 45 mL/minute/1.73 m² and recent isolates are susceptible. This targeted post-trigger strategy also fits her wish to minimise antibiotic exposure. A is premature: continuous antibiotic prophylaxis is considered after less intensive applicable options, including single-dose prophylaxis, have not worked. B is also later in the prevention sequence; methenamine hippurate is considered when behavioural measures and applicable single-dose prophylaxis have not adequately improved recurrence. C treats breakthrough symptomatic infection rather than preventing a predictable post-coital episode. E has the correct prophylactic strategy and dose structure, but cefalexin is unsuitable because her recent isolates are resistant.

Reference: NICE NG112: Urinary tract infection (recurrent): antimicrobial prescribing — Recommendations (2018; updated May 2025) — https://www.nice.org.uk/guidance/ng112/chapter/recommendations NICE NG112: Urinary tract infection (recurrent): antimicrobial prescribing — Table 1 (2018; updated May 2025) — https://www.nice.org.uk/guidance/ng112/chapter/recommendations NICE NG112: Urinary tract infection (recurrent): antimicrobial prescribing — Sequencing of prophylaxis (2018; updated May 2025) — https://www.nice.org.uk/guidance/ng112/chapter/recommendations