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

Benign prostatic hyperplasia (BPH) is a non-malignant proliferation of the stromal and epithelial cells of the prostate gland that causes progressive enlargement of the transition zone surrounding the urethra. BPH is the most common benign tumour in men and is an almost universal feature of ageing male anatomy — histological evidence is present in 50% of men in their 50s and over 90% of men in their 80s. Clinically, BPH causes lower urinary tract symptoms (LUTS) — a combination of obstructive (voiding) and irritative (storage) symptoms — affecting 25% of men with significant quality-of-life impact. BPH is distinct from prostate cancer, which arises from the peripheral zone. The prostate undergoes a second growth phase from puberty onwards under androgenic stimulation, explaining why BPH does not occur before puberty and is absent in castrated males.

Androgens are the primary hormonal driver — testosterone is converted to dihydrotestosterone (DHT) in the prostate by 5-alpha reductase type 2, and DHT binds the androgen receptor to drive epithelial and stromal cell proliferation. Men with 5-alpha reductase deficiency or early castration never develop BPH. Oestrogen may also play a role — as men age, testosterone declines while oestradiol levels remain relatively stable, altering the androgen:oestrogen balance. Insulin and insulin-like growth factors contribute to prostate cell growth — explaining the association with metabolic syndrome. Risk factors: age (the dominant factor), family history (first-degree relatives with BPH double the risk), metabolic syndrome (obesity, diabetes, dyslipidaemia), physical inactivity, and excessive alcohol consumption. BPH is more prevalent in Western countries compared to Asia — possibly related to diet (red meat, high saturated fat), environmental factors, or differences in reporting.

BPH causes two categories of lower urinary tract symptoms (LUTS). Storage (irritative) symptoms: urinary frequency (>8 voids per day), urgency (sudden compelling desire to void — difficult to defer), urge incontinence (leakage with urgency), nocturia (waking ≥2 times per night to void — often the most bothersome symptom). Voiding (obstructive) symptoms: weak urinary stream (slow, reduced force), hesitancy (difficulty initiating urination), intermittency (starting and stopping mid-stream), straining to void, sensation of incomplete bladder emptying, terminal dribbling. Post-micturition symptoms: post-void dribble, feeling of incomplete emptying. Symptom severity is quantified by the International Prostate Symptom Score (IPSS) and quality-of-life question — scores 0–7 (mild), 8–19 (moderate), 20–35 (severe). Complications of untreated BPH: urinary retention (acute — painful; chronic — painless but high residual urine), recurrent urinary tract infections, bladder stone formation, upper tract dilatation (hydroureteronephrosis), and rarely renal impairment.

Digital rectal examination (DRE): assesses prostate size, consistency, and symmetry — enlargement in BPH is smooth, rubbery, symmetrical (hard or asymmetrical nodules raise cancer concern). IPSS questionnaire: standardises symptom severity; guides treatment intensity. Urinalysis: dipstick and MSU to exclude infection (UTI) and haematuria (bladder cancer, stones). Prostate-specific antigen (PSA): elevated in BPH (up to 1 ng/mL per 10 g prostate volume), but also raised in prostatitis and prostate cancer. Free/total PSA ratio and PSA density help differentiate BPH from cancer. PSA is offered after counselling about implications. Uroflowmetry: objective flow rate measurement — peak flow (Qmax) <10 mL/s suggests obstruction; 10–15 mL/s equivocal; >15 mL/s normal. Post-void residual (PVR) ultrasound: residual urine >200 mL indicates incomplete bladder emptying and increases UTI and retention risk. Transrectal ultrasound (TRUS): measures prostate volume accurately — important for selecting medical treatment (finasteride more effective for large prostate >40 mL). Cystoscopy: if haematuria, urgency, or suspected bladder pathology. Pressure-flow urodynamics: for complex cases or prior to surgery — differentiates BPH obstruction from detrusor underactivity.

Watchful waiting with lifestyle modification: for mild-moderate symptoms (IPSS ≤7) — fluid restriction in evenings, reduction of caffeine and alcohol, double voiding (void, wait, void again), urethral milking to reduce dribble, bladder training. Alpha-1 adrenergic receptor antagonists (alpha blockers): tamsulosin 400 mcg OD (most uroselective), alfuzosin, silodosin, doxazosin — relax smooth muscle in the prostate and bladder neck, improving urine flow. Onset of action within days; most effective medication for symptom relief but do not reduce prostate size. Side effects: postural hypotension (especially doxazosin), retrograde ejaculation (tamsulosin, silodosin — 10–30%). 5-Alpha reductase inhibitors (5-ARIs): finasteride 5 mg OD or dutasteride 0.5 mg OD — block DHT synthesis, causing prostate to shrink by 20–30% over 6 months. Effective in prostate >30–40 mL; reduce retention risk and PSA by 50% (important for cancer screening interpretation). Combination therapy (alpha blocker + 5-ARI — e.g., CombAT trial: dutasteride + tamsulosin): superior to monotherapy for moderate-severe BPH with large prostate — reduces symptoms and risk of acute urinary retention by 67%. Phosphodiesterase-5 inhibitors (tadalafil 5 mg OD): approved for LUTS/BPH, particularly in patients with erectile dysfunction. Surgical options: transurethral resection of the prostate (TURP — gold standard surgical treatment: resection of obstructing prostate tissue under cystoscopy, immediate and durable symptom relief); laser enucleation of the prostate (HoLEP — superior to TURP for large prostates, less bleeding, lower retrograde ejaculation rate, shorter hospital stay); Rezum water vapour thermal therapy (minimally invasive); Urolift (mechanical retraction of prostate lobes — no ejaculatory side effects); aquablation (robotic water jet). Open or laparoscopic simple prostatectomy for very large prostates (>100 mL).

Benign prostatic hyperplasia (BPH) — when inadequately treated — causes progressive complications from bladder outlet obstruction that can significantly impair quality of life and lead to serious urological complications. Acute urinary retention (AUR): a medical emergency — complete inability to void despite a full bladder; occurs in 1-2% of men with BPH per year; precipitated by anticholinergic medications, cold weather, alcohol, and prolonged voluntary urinary retention; requires urgent catheterisation and subsequent surgical management. Chronic urinary retention: gradual bladder distension with residual urine volumes above 300 ml; often painless due to bladder adaptation; can be detected only on examination or imaging; leads to overflow incontinence. Bladder dysfunction: chronic outlet obstruction causes detrusor muscle hypertrophy initially, followed by decompensation — bladder contractility fails, leading to impaired emptying even after prostate treatment. Bladder calculi (stones): urinary stasis from incomplete bladder emptying predisposes to calcium oxalate and calcium phosphate stone formation; causes haematuria and worsening LUTS. Recurrent urinary tract infections: urinary stasis is a major risk factor for bacterial colonisation and UTI (E. coli, Klebsiella); ascending infection can cause pyelonephritis. Hydronephrosis and chronic kidney disease: bilateral ureteric obstruction from severe BPH causes progressive hydronephrosis, renal cortical atrophy, and chronic kidney disease — may present as uraemia.

Regular physical activity reduces LUTS severity by 25% — exercise reduces sympathetic adrenergic tone in the prostate and bladder neck. Maintain healthy body weight — obesity is an independent risk factor for BPH and LUTS severity. Plant-based diet with high soy isoflavone content may have a protective effect (explaining lower Asian prevalence). Reduce red meat and saturated fat intake. Moderate alcohol consumption — avoid excess. Reduce evening fluid intake (avoid drinks after 6 pm), avoid caffeine and carbonated drinks which irritate the bladder, and practice double voiding. Saw palmetto (Serenoa repens) herbal extract: widely used but large placebo-controlled trials show no benefit over placebo for LUTS. Annual PSA monitoring in men with BPH (PSA velocity >0.75 ng/mL/year suggests cancer risk even with a normal absolute PSA).

Go to the emergency department immediately if you are unable to pass urine at all (acute urinary retention) — this requires emergency bladder catheterisation. Seek same-day medical review for: sudden inability to void, severe suprapubic pain, fever with urinary symptoms (suggesting pyelonephritis), or visible blood in urine. See your GP or urologist within 1–2 weeks for: significant worsening of urinary symptoms, IPSS score above 8 affecting quality of life, nocturia causing sleep disruption, or recurrent urinary tract infections. All men with LUTS should have PSA measured after appropriate counselling — not to diagnose prostate cancer, but to establish a baseline and identify those who may benefit from prostate cancer investigation.