A 72-year-old man from Mumbai with a 3-year history of BPH managed on tamsulosin 0.4 mg daily presents with acute inability to void. He has suprapubic pain and a palpable bladder. Postvoid residual is immeasurable (bladder full). Serum creatinine is 1.2 mg/dL (baseline 0.9 mg/dL). Urinalysis shows no infection. What is the most appropriate immediate management?

Explanation

## Acute Urinary Retention in BPH: Management Algorithm **Key Point:** Acute urinary retention (AUR) in BPH is a medical emergency requiring **immediate catheterization** to relieve obstruction, prevent renal damage, and allow assessment of detrusor function. ### Acute Retention: Immediate vs. Delayed Management ```mermaid flowchart TD A[Acute urinary retention]:::urgent --> B[Insert catheter immediately]:::action B --> C{Catheter type?}:::decision C -->|First episode, stable| D[Transurethral catheter]:::action C -->|Contraindication to TU catheter| E[Suprapubic catheter]:::action D --> F[Drain bladder over 30-60 min]:::action F --> G[Monitor urine output, renal function]:::action G --> H{Trial of void after 48-72 hrs?}:::decision H -->|Success| I[Remove catheter, optimize medical therapy]:::outcome H -->|Failure| J[Proceed to TURP]:::action ``` **High-Yield:** In **first-episode AUR** without contraindications (e.g., urethral stricture, recent TURP), **transurethral catheterization** is the standard approach. Suprapubic catheterization is reserved for cases with urethral contraindications or recurrent AUR [cite:Harrison 21e Ch 297]. ### Why Transurethral Catheter in This Case? 1. **First episode of AUR** — no prior urethral trauma or stricture mentioned. 2. **Stable renal function** — creatinine only mildly elevated (1.2 mg/dL); no obstructive uropathy yet. 3. **No contraindications** — no history of urethral stricture, recent TURP, or prostate cancer. 4. **Standard practice** — TU catheter is less morbid than suprapubic approach for initial management. ### Post-Catheterization Protocol **Clinical Pearl:** After catheter insertion: - Drain bladder **slowly over 30–60 minutes** to avoid post-obstructive diuresis and electrolyte imbalance. - Monitor **urine output, serum creatinine, and electrolytes** for 48–72 hours. - Perform **trial of void (TOV)** after 48–72 hours of catheter drainage. - If TOV successful (post-void residual <100 mL), remove catheter and optimize medical therapy (alpha-blocker ± 5-alpha reductase inhibitor). - If TOV fails, proceed to **TURP** (definitive treatment for obstructive BPH). ### Why Not Other Options? **Observation without catheterization:** - Acute retention with a palpable bladder is a **medical emergency**. Prolonged obstruction risks acute kidney injury, bladder decompensation, and permanent detrusor dysfunction. - Spontaneous voiding is unlikely without intervention. **Suprapubic catheterization as first-line:** - Reserved for **contraindications to TU catheter** (e.g., urethral stricture, recent TURP, penile trauma). - More invasive and morbid than TU catheter for initial AUR. **Antibiotics and increased alpha-blocker:** - Antibiotics are not indicated (no UTI on urinalysis). - Increasing alpha-blocker dose will not relieve acute obstruction; the bladder is already decompensated. - Medical therapy alone cannot manage acute retention. **Mnemonic:** **AUR Management = CAT** - **C**atheterize immediately (TU or suprapubic) - **A**ssess post-obstructive diuresis and renal function - **T**rial of void after 48–72 hours; if fails → TURP