Prostate Enlargement (BPH) — Causes, Symptoms & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Benign prostatic hyperplasia (BPH) — prostate enlargement — is a non-cancerous, age-related condition characterised by hyperplasia (increase in cell number) of the stromal and glandular elements of the transition zone of the prostate gland, leading to progressive enlargement that can compress the urethra and cause lower urinary tract symptoms (LUTS). BPH is extremely prevalent: histological evidence of BPH is found in 50% of men by age 60 and 90% by age 85. LUTS attributable to BPH affect approximately 30% of men over 65. BPH is benign — it does not cause prostate cancer and does not predispose to it. However, untreated significant BPH can lead to acute urinary retention, recurrent UTI, bladder diverticula, hydronephrosis, and chronic kidney injury. Effective medical and surgical treatments are available.

The pathogenesis of BPH involves dihydrotestosterone (DHT) — the active androgen metabolite in the prostate (converted from testosterone by 5-alpha-reductase). DHT drives prostate stromal and epithelial proliferation via androgen receptor activation. Oestrogen may also play a role in stromal proliferation (oestrogen:testosterone ratio rises with age). The fundamental cause of BPH is the confluence of androgens and ageing — men castrated before puberty do not develop BPH. Risk factors: age (strongest — BPH is virtually universal with advancing age), family history (first-degree relatives with BPH — 4x increased risk), obesity (insulin resistance and metabolic syndrome increase BPH risk), sedentary lifestyle, type 2 diabetes, erectile dysfunction (shared pathophysiology), and race (Black men have more severe BPH; Asian men have lower rates).

LUTS (lower urinary tract symptoms) are classified as: Obstructive (voiding) symptoms: hesitancy (difficulty initiating urination), weak or intermittent urinary stream, straining to void, sensation of incomplete bladder emptying, terminal dribbling, and urinary retention (acute — inability to void; or chronic — high post-void residual). Irritative (storage) symptoms: urinary frequency (voiding more than 8 times in 24 hours), nocturia (waking 1+ times per night to void — highly prevalent and distressing), urgency (sudden compelling need to urinate), and urgency urinary incontinence. Symptom severity assessment: International Prostate Symptom Score (IPSS) — 7-item validated questionnaire scoring severity (mild 0-7, moderate 8-19, severe 20-35) and quality of life impact. A rectal examination (digital rectal exam — DRE) assesses prostate size and consistency — smoothly enlarged, rubbery prostate consistent with BPH. Complications: acute urinary retention (sudden inability to pass urine — medical emergency requiring catheterisation), haematuria, recurrent UTI, bladder stones, and obstructive nephropathy.

Urinalysis and urine culture: exclude UTI, haematuria, and glucose (diabetes). PSA (Prostate-Specific Antigen) blood test: essential to exclude prostate cancer — PSA is elevated in BPH (proportional to prostate volume), prostatitis, and prostate cancer; interpretation requires age-adjusted ranges and DRE findings; PSA should be offered with counselling about implications before testing. Renal function (U&E, creatinine): assess for obstructive nephropathy in severe LUTS. Post-void residual (PVR) measurement: bladder ultrasound after voiding — PVR above 300ml indicates significant retention. Uroflowmetry: objective measurement of urinary flow rate — maximum flow rate (Qmax) below 10 ml/s indicates significant obstruction. Ultrasound of kidneys and bladder (abdominal): assesses upper tract, prostate volume, bladder wall thickness (trabeculation from chronic retention), and post-void residual. Flexible cystoscopy: indicated if haematuria, to exclude bladder cancer or stricture. Transrectal ultrasound (TRUS): accurate prostate volume measurement — guides treatment selection (5-ARI more effective for large prostates above 30-40ml). Urodynamics: in atypical presentations or when bladder overactivity vs. obstruction needs differentiation.

Watchful waiting: appropriate for mild LUTS (IPSS below 8) without complications — active monitoring with lifestyle advice (reduce evening fluids, limit caffeine and alcohol, double voiding, bladder training). Medical treatment: Alpha-1 adrenoceptor antagonists (alpha-blockers) — tamsulosin (0.4mg daily), alfuzosin, doxazosin, terazosin: relax prostate smooth muscle and internal urethral sphincter; rapid onset (1-2 weeks); most effective for obstructive symptoms; first-line for moderate-severe LUTS. Side effects: retrograde ejaculation (particularly tamsulosin — 10-30%), orthostatic hypotension (less with tamsulosin — uro-selective). 5-Alpha-reductase inhibitors (5-ARIs) — finasteride (5mg daily), dutasteride (0.5mg daily): reduce prostate volume by blocking DHT synthesis; effective for large prostates (above 30-40ml); takes 3-6 months for symptom improvement; also reduce PSA by approximately 50% (must be doubled for cancer risk interpretation); prevent disease progression and reduce acute retention and surgical risk. Combination therapy (alpha-blocker + 5-ARI): superior to either agent alone for large prostates — most effective for preventing disease progression. Antimuscarinics (oxybutynin, solifenacin) or mirabegron (beta-3 agonist) for predominant irritative/OAB symptoms — but with caution in men with high PVR (risk of retention). Surgical treatment: TURP (Transurethral Resection of the Prostate) — gold standard surgical treatment; endoscopic removal of obstructing prostate tissue; 85-90% symptom improvement; retrograde ejaculation in 65-90%; urinary incontinence rare. HoLEP (Holmium Laser Enucleation of the Prostate): increasingly preferred over TURP, especially for large prostates — lower blood loss, catheter time, and hospital stay; equivalent or superior symptom outcomes. GreenLight PVP (photovaporisation): laser vaporisation — suitable for men on anticoagulation. UroLift (prostatic urethral lift): minimally invasive, preserves ejaculatory function — suitable for smaller prostates. Acute urinary retention: immediate urethral catheterisation, trial without catheter (TWOC) after 2-7 days on tamsulosin, then surgical intervention if TWOC fails.

Acute urinary retention (AUR — the most common acute complication; sudden inability to pass urine despite a painful distended bladder, occurring in 1-2% of men with symptomatic BPH per year; precipitated by alpha-sympathomimetic drugs, anticholinergics, anaesthesia, and constipation; requires emergency urethral or suprapubic catheterisation followed by a trial without catheter on tamsulosin; surgical TURP is indicated after two episodes). Recurrent urinary tract infections (ascending cystitis and prostatitis from chronically elevated post-void residual urine — a culture-positive UTI in a man requires urological assessment). Bladder calculi (bladder stones forming in stagnant residual urine — cause recurrent haematuria, irritative LUTS, and require cystoscopic removal combined with TURP). High-pressure chronic urinary retention and renal impairment (silent painless bilateral hydronephrosis and progressive renal impairment from sustained high-pressure BPH obstruction — post-void residual above 300 mL with bilateral hydronephrosis requires emergency catheterisation and urgent urological assessment). Detrusor decompensation (irreversible damage to the bladder muscle from prolonged obstruction — results in an atonic bladder that may not recover contractile function even after successful prostate surgery). Bladder diverticula (outpouchings of bladder mucosa through weak points in the detrusor wall — harbour residual urine, predisposing to recurrent infections and stone formation).

BPH cannot be prevented due to its androgen-dependent and age-related nature, but lifestyle measures can modify symptoms and slow progression. Maintain healthy weight: obesity increases BPH risk and symptom severity — weight reduction improves LUTS. Regular moderate physical activity reduces BPH risk and severity (Exercise and BPH — multiple observational studies). Reduce fluid intake in the evening (limit after 6pm) to reduce nocturia. Limit caffeine (bladder irritant — increases urinary frequency and urgency) and alcohol (diuretic effect, irritant). Double voiding (urinating, then waiting 30 seconds and urinating again) empties the bladder more completely. Bladder training exercises: gradually increasing the time between voiding episodes trains the bladder. Avoid anticholinergic medications (some antihistamines, cold remedies — can precipitate acute retention in BPH). Regular PSA and prostate monitoring as recommended by your GP — to ensure prostate cancer is detected early.

See your GP for: difficulty urinating, significantly reduced urinary stream, frequent urination that is interfering with daily life or sleep, or feeling that the bladder is not completely emptying after urination. Any man over 50 with lower urinary tract symptoms should have a PSA test after counselling, to assess prostate cancer risk. Seek emergency care immediately for acute urinary retention — sudden complete inability to pass urine with painful bladder distension. Do not delay as this can cause bladder and kidney injury. Also seek urgent assessment for: haematuria (blood in urine — may indicate bladder cancer, not just BPH), fever with urinary symptoms (obstructed infected urinary tract), or new onset of urinary symptoms after previous stability.