Which investigations should be performed after a first episode of urinary tract infection in men?

Following a first male urinary tract infection (mUTI), systematic investigation for predisposing factors is called for, as mUTIs frequently arise secondarily to anatomical or functional urinary tract abnormalities. Although no international consensus defines a minimal etiological work-up, guidelines from the French (AFU) and European (EAU) Associations of Urology provide a clinical framework. First-line assessment comprises a targeted history (laying emphasis on macroscopic hematuria and lower urinary tract symptoms, LUTS), digital rectal examination (DRE), the International Prostate Symptom Score (IPSS), and urinary tract ultrasonography with post-void residual (PVR) measurement. LUTS, classified as storage (urgency, frequency), voiding (weak stream, straining), or post-micturition (incomplete emptying) may indicate benign prostatic hyperplasia (BPH), the leading aetiology in men over 50. Ultrasound evaluates prostate volume, bladder morphology, and PVR; voiding diaries complement assessment when storage LUTS predominate. Alpha-blockers represent first-line therapy for BPH-related LUTS. Routine PSA testing following mUTI is not recommended, as elevations are non-specific: prostatitis may raise PSA independently of malignancy, and levels can remain elevated up to three months post-infection. No association exists between a first mUTI and prostate cancer, nor between PSA and UTI recurrence. Second-line referral is indicated for pyelonephritis, urinary retention, macroscopic hematuria, IPSS >7, PVR >100 mL, recurrent UTI, age under 40, or imaging abnormalities. Cross-sectional imaging (CT or MRI) is reserved for suspected obstruction, severe presentations, or treatment failure. This stratified approach optimizes cost-effectiveness, ensuring identification of underlying pathology (BPH, urolithiasis, or malignancy) while avoiding unnecessary investigations.