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Asymptomatic bacteriuria in an older adult with delirium — MSRA MCQ

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HardUrinary Tract InfectionsAsymptomatic bacteriuria in an older adult with deliriumMSRA

An 86-year-old woman living in a care home is reviewed for new inattention and drowsiness over 24 hours. She has vascular dementia but is normally able to hold a coherent conversation. Her 4AT score is 6. She reports no dysuria, suprapubic pain, loin pain, urgency or visible haematuria. Staff have observed no new incontinence or frequency. She has no catheter. Her temperature is 37.2°C, heart rate 82 beats/minute, blood pressure 132/74 mmHg and respiratory rate 16 breaths/minute. Oxygen saturation is 96% on air. A urine dipstick performed by staff because the urine smelled strong was positive for nitrites and leucocytes; a urine culture subsequently grew >10⁵ CFU/mL Escherichia coli. She started codeine 3 days ago after a vertebral compression fracture and has not opened her bowels for 4 days; examination suggests faecal loading. There are no focal neurological signs. What is the most appropriate immediate management plan?

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Correct answer: E — Withhold antibiotics, address likely non-urinary precipitants of delirium, and safety-net for new localising or systemic features of infection

This presentation is most consistent with delirium with asymptomatic bacteriuria (ASB), not symptomatic UTI. She has neither new localising urinary symptoms nor systemic features of infection. In older adults, particularly care-home residents, bacteriuria and pyuria are common, so nitrite/leucocyte dipsticks and a positive urine culture cannot distinguish colonisation from infection. Culture should guide antibiotic selection only when the clinical syndrome indicates that treatment is required. There are credible non-urinary precipitants: recent codeine exposure and faecal loading. These should be addressed while undertaking a standard delirium assessment and providing safety-netting for fever, haemodynamic deterioration, new dysuria, suprapubic pain, flank pain or other evolving infectious features. A and C incorrectly treat culture positivity rather than the patient; nitrofurantoin or cefalexin would become relevant only if she developed a clinically supported lower UTI, guided by susceptibility and renal function. D remains inappropriate because repeat culture in an asymptomatic older person is likely to reproduce ASB and promote unnecessary prescribing. E overinterprets a dipstick result and is not justified in a haemodynamically stable patient without sepsis or pyelonephritis.

Reference: Diagnosis of urinary tract infections: quick reference tools for primary care (Updated 7 July 2025) — https://www.gov.uk/government/publications/urinary-tract-infection-diagnosis/diagnosis-of-urinary-tract-infections-quick-reference-tools-for-primary-care Urinary tract infection (lower): antimicrobial prescribing (NG109), recommendations (Published 31 October 2018; minor updates through May 2025) — https://www.nice.org.uk/guidance/ng109/chapter/Recommendations