BPH

**Pathophysiology** - Hyperplasia (not hypertrophy alone) of stromal and epithelial cells in the **transition (periurethral) zone**. Cancer, by contrast, arises most often in the peripheral zone. - Driven by **dihydrotestosterone (DHT)**, which is converted from testosterone by **5α-reductase** in prostate cells. Aging-related increases in the estrogen:androgen ratio may also contribute by increasing androgen receptor sensitivity. - Static component: bulk of the enlarged gland compresses the urethra. Dynamic component: α1-adrenergic-mediated smooth muscle tone in the prostate and bladder neck. - Incidence rises with age (about 50% of men at age 50, up to about 90% by age 80).

**Clinical presentation (LUTS)** - Obstructive: hesitancy, weak or intermittent stream, straining, incomplete emptying, post-void dribbling, urinary retention. - Irritative (storage): urgency, frequency, nocturia. - Exam: symmetrically enlarged, smooth, firm, rubbery prostate on DRE. A hard, asymmetric nodule suggests cancer. A tender, boggy prostate suggests prostatitis.

**Complications** - Acute or chronic urinary retention, overflow incontinence. - Recurrent UTIs, bladder stones. - Bladder wall trabeculation and diverticula. - Hydronephrosis, post-renal AKI, and obstructive uropathy. - Detrusor hypertrophy, then decompensation.

**Diagnosis** - Clinical, with the IPSS (AUA symptom score), DRE, and UA to rule out infection or hematuria. - Serum creatinine if renal impairment is suspected. - **PSA may be mildly elevated** in BPH. It also rises with prostatitis, urinary retention, and instrumentation or catheterization. Ejaculation has a smaller effect. - Post-void residual (bladder scan) and uroflowmetry can be added.

**Management** - Mild: watchful waiting and lifestyle changes (reduce evening fluids, caffeine, and alcohol; avoid decongestants and anticholinergics). - **α1-blockers** (tamsulosin, alfuzosin, silodosin are α1A-selective; terazosin and doxazosin are nonselective): - They relax prostatic and bladder neck smooth muscle, so they work fast. - Adverse effects: orthostatic hypotension, dizziness, retrograde ejaculation, and **intraoperative floppy iris syndrome** (tamsulosin). - **5α-reductase inhibitors** (finasteride, dutasteride): - They shrink the prostate over months and work best for large glands. - Adverse effects: decreased libido, erectile dysfunction, gynecomastia. - They lower PSA by about 50%, so double the measured value when screening. - **PDE-5 inhibitors** (tadalafil) are used when BPH coexists with erectile dysfunction. - **Antimuscarinics or β3 agonists** may be added for predominantly storage symptoms (with a post-void residual check). - **Surgery**: TURP is the classic procedure. Complications include retrograde ejaculation, TURP syndrome (hyponatremia from absorbed hypotonic irrigant), and incontinence. Other options include laser enucleation and minimally invasive procedures. - Indications for surgery: refractory retention, recurrent UTIs, bladder stones, recurrent hematuria, renal insufficiency, or failed medical therapy.

**High-yield comparisons** - BPH: transition zone, smooth and symmetric enlargement, obstructive LUTS. - Prostate adenocarcinoma: peripheral zone, hard irregular nodule, elevated PSA, osteoblastic bone metastases. - Prostatitis: tender prostate, dysuria, fever (acute bacterial).

**Board pearls** - Elderly man with nocturia and weak stream, then a smooth enlarged prostate: BPH. - Fastest symptom relief: α1-blocker. Reduces prostate size: 5α-reductase inhibitor. - Combination therapy (α-blocker plus 5-ARI) is best for large prostates with significant symptoms. - Histology: nodular hyperplasia with glands lined by two cell layers (basal and luminal) and papillary infoldings. Cancer lacks the basal layer.