Benign Prostatic Enlargement

Benign prostatic enlargement is non-malignant growth of the stromal and glandular tissue of the transition zone of the prostate (benign prostatic hyperplasia histologically). Benign prostatic enlargement (BPE) is the enlarged gland; bladder outlet obstruction (BOO) is the functional consequence.

• Androgen dependent: dihydrotestosterone formed by 5-alpha reductase drives growth. Histological hyperplasia is present in about 50 percent of men aged 50, 70 percent at 60, and 80 to 90 percent by age 80. Clinically significant symptoms develop in about a third.
• Risk factors: age, family history, obesity, diabetes, metabolic syndrome, physical inactivity, high alcohol intake.
• Symptoms result from the static component (volume) and dynamic component (smooth muscle tone via alpha-1 adrenoceptors), plus secondary detrusor overactivity.
• Complications: acute urinary retention (risk increases with age, symptom score, prostate volume above 30 mL, PSA above 1.4 ng/mL, residual volume), chronic retention with overflow, recurrent infection, bladder stones, haematuria, bladder diverticula, hydronephrosis and renal failure.

• Voiding: hesitancy, weak or intermittent stream, straining, terminal dribbling, incomplete emptying.
• Storage: frequency, urgency, nocturia, urgency incontinence.
• Severity from IPSS (0 to 7 mild, 8 to 19 moderate, 20 to 35 severe) plus the bother score.
• Examination: abdomen for a palpable bladder, genitalia (phimosis, meatal stenosis), digital rectal examination (smooth, symmetrical, firm enlarged gland with a preserved median sulcus; hard, nodular or fixed gland suggests cancer; tender boggy gland suggests prostatitis), neurological examination of the lower limbs and perineum, oedema.
• Red flags: visible haematuria, painful retention, fever, renal impairment, back pain, weight loss, hard irregular prostate, raised PSA for age, recurrent infection, bladder stone symptoms, neurological signs.

• Urinalysis and culture; bloods: urea, creatinine, eGFR, glucose, PSA after counselling on benefits and harms (PSA above about 1.5 ng/mL in men aged over 50 predicts prostate volume above 30 mL).
• Frequency volume chart (3 days).
• Uroflowmetry: Qmax below 10 mL/s with voided volume at least 150 mL suggests obstruction; 10 to 15 mL/s equivocal.
• Post-void residual by bladder scan: persistent residual over 100 to 150 mL suggests incomplete emptying; over 300 mL suggests chronic retention.
• Renal tract ultrasound for haematuria, residual, recurrent infection, renal impairment; prostate volume measurement by transrectal or abdominal ultrasound.
• Prostate MRI and biopsy if PSA is raised or the gland feels abnormal.
• Cystoscopy for haematuria, stricture or bladder tumour; urodynamic pressure flow study before surgery in uncertain cases.
• Differential: prostate cancer, urethral stricture, bladder neck stenosis, detrusor underactivity, neurogenic bladder, chronic prostatitis, bladder cancer, overactive bladder.

• Mild symptoms or low bother: watchful waiting, lifestyle (reduce evening fluids, caffeine and alcohol; double voiding; timed voiding; treat constipation; review drugs such as anticholinergics, decongestants, diuretics, antidepressants and calcium channel blockers).
• Alpha-1 blockers (first line for moderate to severe symptoms; improve flow by about 2 to 3 mL/s and symptom score by 30 to 40 percent within days):
  • Tamsulosin 400 micrograms orally once daily after the same meal (modified release capsule; do not crush).
  • Alfuzosin 10 mg modified release orally once daily after food.
  • Doxazosin 1 mg orally at night, titrated at 1 to 2 week intervals to 2 mg, 4 mg and up to 8 mg daily (also lowers blood pressure; first dose syncope).
  • Silodosin 8 mg orally once daily with food (more retrograde ejaculation; dose 4 mg in moderate renal impairment).
  • Side effects: dizziness, postural hypotension, retrograde ejaculation, nasal congestion, intraoperative floppy iris syndrome (inform the ophthalmologist before cataract surgery). Review at 4 to 6 weeks.
• 5-alpha reductase inhibitors (prostate volume above 30 to 40 mL or PSA above 1.4 ng/mL; reduce volume by about 20 to 30 percent over 6 months, lower retention and surgery risk by about half over 4 years):
  • Finasteride 5 mg orally once daily; dutasteride 500 micrograms orally once daily.
  • Side effects: reduced libido, erectile dysfunction, ejaculatory disorders, gynaecomastia, depressive symptoms. PSA falls by about 50 percent after 6 to 12 months (double the measured value for interpretation). Women who are or may be pregnant must not handle crushed or broken tablets.
• Combination of an alpha blocker with a 5-alpha reductase inhibitor for moderate to severe symptoms and enlarged prostate; after 6 to 12 months the alpha blocker can be stopped in men with improved symptoms.
• Tadalafil 5 mg orally once daily (men with coexisting erectile dysfunction; contraindicated with nitrates and caution with alpha blockers and in severe renal impairment).
• Storage symptoms persisting on an alpha blocker with a residual under 150 mL: add an antimuscarinic (solifenacin 5 mg daily, tolterodine 2 mg twice daily) or mirabegron 50 mg daily; recheck residual urine after 4 to 8 weeks.
• Nocturnal polyuria: desmopressin melt 50 micrograms sublingually one hour before bed in men, with sodium monitoring (baseline, day 3 and 1 month).
• Acute urinary retention: urethral catheter (record drained volume; over 1 litre or renal impairment warrants admission and monitoring for post-obstructive diuresis); start tamsulosin 400 micrograms daily (or alfuzosin 10 mg) for at least 3 days; remove the catheter after 2 to 3 days to test voiding; refer to urology if it fails.
• Surgery (urology): transurethral resection of the prostate, laser enucleation (holmium or thulium), photoselective vaporisation, prostatic urethral lift, water vapour thermal therapy, aquablation, prostatic artery embolisation, open or robotic simple prostatectomy for glands over 80 to 100 mL. Indications: refractory retention, recurrent urinary infection, bladder stones, recurrent haematuria from the prostate, renal impairment from obstruction, or failure or intolerance of medical therapy. Postoperative risks: retrograde ejaculation (65 to 75 percent), bleeding, stricture, incontinence, erectile dysfunction.
• Review annually (symptom score, residual, PSA, medication adherence). Refer urgently for suspected prostate cancer, visible haematuria or retention with renal impairment.