A 58-year-old man with benign prostatic hyperplasia (BPH) presents with lower urinary tract symptoms (LUTS). He is started on an alpha-1 blocker. Before initiating therapy, which investigation is most appropriate to exclude secondary causes of LUTS and assess baseline urinary function?

Explanation

## Investigation of Choice for LUTS Before Alpha-Blocker Initiation ### Clinical Context Before starting an alpha-1 blocker for presumed BPH, it is essential to exclude urinary tract infection (UTI) and other secondary causes of LUTS that may mimic or coexist with BPH. ### Why Urinalysis and Urine Culture? **Key Point:** Urinalysis and urine culture are the **first-line investigations** to exclude UTI, hematuria, and pyuria—all of which can present with LUTS and must be ruled out before attributing symptoms to BPH alone. **High-Yield:** Untreated UTI can cause or worsen LUTS; treating the infection may resolve symptoms without need for alpha-blockers. Hematuria on urinalysis warrants further investigation (ultrasound, cystoscopy) to exclude malignancy. ### Role of Other Investigations | Investigation | Timing | Purpose | |---|---|---| | **Urinalysis + culture** | **Before alpha-blocker** | Exclude UTI, pyuria, hematuria | | PVR by ultrasound | After initial assessment | Assess degree of obstruction; guides therapy escalation | | PSA | Baseline (separate discussion) | Prostate cancer screening; not mandatory before alpha-blocker | | Cystoscopy | Only if hematuria or obstruction suspected | Invasive; reserved for specific indications | ### Clinical Pearl A positive urine culture with symptoms of dysuria and frequency may indicate acute cystitis rather than BPH. Treating the infection first is standard practice; alpha-blockers are added only if LUTS persist after UTI resolution. ### Guideline Alignment International guidelines (EAU, AUA) recommend urinalysis as a baseline investigation in all men presenting with LUTS to exclude reversible causes before attributing symptoms to BPH.