Synopsis
Diagnose lower urinary tract infection without overcalling colonisation, identify upper-tract or septic disease and prescribe short, safe, susceptibility-aware treatment for distinct adult groups.
- Lower urinary tract infection causes dysuria, frequency, urgency and suprapubic discomfort without fever, flank pain or systemic illness.
- In women under 65, a symptom-led diagnostic approach is useful; vaginal discharge or irritation makes urinary infection less likely.
- Culture urine before treatment in pregnancy and men, and when recurrent, resistant-risk, atypical, severe or failing to improve.
Key red flags
Fever, rigors, flank pain or costovertebral-angle tenderness suggests upper urinary tract infection.
Fever, rigors, loin pain, vomiting or costovertebral-angle tenderness should be managed as possible pyelonephritis rather than uncomplicated cystitis.
Investigation priorities
Estimate lower UTI probability and identify upper-tract, genital or systemic features.
Management branches
A non-pregnant woman has a convincing lower urinary syndrome without systemic, flank or vaginal features.
- Assess symptom combination, previous cultures, resistance risk, renal function and immediate allergy and give self-care and safety-net advice.
- Use nitrofurantoin 100 mg modified-release twice daily for three days when eGFR is at least 45 mL/minute, or trimethoprim 200 mg twice daily for three days when resistance risk is low.
Key medicines
Nitrofurantoin modified releaseGive 100 mg orally twice daily for three days in non-pregnant women or seven days in men when prostate involvement is not suspected.
TrimethoprimGive 200 mg orally twice daily for three days in non-pregnant women or seven days in men when resistance risk is low.