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Benign Prostatic Hyperplasia

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Overview

Benign prostatic hyperplasia (BPH) describes the non-malignant hyperplasia of the prostate and is commonly seen in older people. It is a significant cause of lower urinary tract symptoms (LUTS), however, they are not synonymous. People presenting with LUTS should not be assumed to have BPH as the only possible cause.

Pathophysiology

Benign prostatic hyperplasia occurs due to an imbalance of cell proliferation and apoptosis, resulting in excess proliferation. This is thought to be due to a combination of factors including hormonal changes. The drugs used for its treatment are thought to induce apoptosis.

Androgens do not directly cause BPH, but they are required for BPH to occur. Testosterone is converted into dihydrotestosterone (DHT) by the enzyme 5-alpha reductase which binds to receptors on prostatic cells and has proliferative and apoptotic effects.

Alpha receptors are present in prostatic smooth muscle which when activated, result in increased tone, narrowing the prostate and bladder neck, resulting in urinary flow obstruction.

Epidemiology

  • BPH can affect up to 90% of people in their 80s and incidence increases with age
  • Around 50% of people >50 years old have evidence of BPH
    • However, only 25-50% of people with BPH have LUTS
  • BPH is more severe in Afro-Caribbean people

Risk Factors

  • Increasing age – 50% of people >50 years old have evidence of BPH
  • Afro-Caribbean ethnicity
  • Family history

Presentation

Overview

Benign prostatic hyperplasia presents with lower urinary tract symptoms which can be divided into:

  • Storage symptoms – the bladder ‘filling too early’ and needing to pass urine sooner:
    • Urgency
    • Polyuria
    • Nocturia
    • Urinary incontinence
    • Feeling the need to urinate again just after passing urine
  • Voiding or obstructive symptoms – problems with urine outflow:
    • Incomplete voiding
    • Poor stream
    • Hesitancy
    • Dribbling
    • Urinary retention
    • Overflow incontinence
  • Post-micturition – problems at the end of passing urine:
    • Post-micturition dribbling
    • Sensation of incomplete emptying

A digital rectal exam should be performed:

  • BPH: smoothly enlarged prostate with a maintained central sulcus
  • If hard, asymmetrical, craggy/nodular, or irregular with loss of the median sulcus, prostate cancer may be possible

Investigations

Overview

Key investigations include:

  • Urine dipstick and analysis:
  • Urea and electrolytes (U&Es):
    • If chronic urinary retention is suspected as this may lead to renal dysfunction
  • Volume charting:
    • This is a diary of the frequency and volume of urine passed to assess patterns of passing urine (e.g. nocturia) and impact
    • Should be done for at least 3 days
  • International Prostate Symptom Score (IPSS):
    • Classifies the severity of symptoms into mild (0-7), moderate (8-19), and severe (20-35)
  • Consider prostate-specific antigen (PSA) testing:
    • Indicated after properly counselling the patient if:
      • Symptoms suggest bladder outlet obstruction
      • The prostate feels abnormal on a digital rectal exam
      • The person is concerned about prostate cancer
    • See Prostate-Specific Antigen (PSA) Testing

Differential Diagnoses

Prostate cancer

  • Although both can present with LUTS, a digital rectal exam may identify a hard, asymmetrical, craggy/nodular, or irregular prostate with loss of the median sulcus in prostate cancer
  • PSA is elevated

Management

Overview

If prostate cancer is unlikely and referral is not indicated, management may involve watching and waiting if symptoms are mild. Further treatment involves:

  • Moderate-severe voiding symptoms (IPSS ≥8): offer alpha-1 antagonist (tamsulosin, alfuzosin)
    • These decrease smooth muscle tone in the prostate and bladder
  • Enlarged prostate and high risk of progression: offer 5-alpha reductase inhibitor (finasteride):
    • This blocks the conversion of testosterone into DHT, resulting in less proliferation and more apoptosis. This reduces the prostate size. It may require up to 6 months to work.
  • Moderate-severe voiding symptoms (IPSS ≥8) + enlarged prostate: consider offering both an alpha-1 antagonist and a 5-alpha reductase inhibitor
  • If storage + voiding symptoms that persist after an alpha-blocker alone: consider an anticholinergic drug (e.g. oxybutynin – avoid this drug in older, frail people)

If initial treatment is unsuccessful, refer to urology for consideration of prostate surgery, which may involve transurethral resection of the prostate (TURP).

Complications

Complications are generally rare but may include:

  • Complications relating to bladder outlet obstruction:
    • Urinary retention and hydronephrosis
    • Recurrent UTI – due to the reduced flow of urine
    • Renal stones – due to the reduced flow of urine
  • Progression of BPH

BPH is not considered to be a precursor to cancer, however, since people with BPH have examinations and tests of the prostate, they may have more incidental discoveries of prostate cancer.

Prognosis

  • With treatment, most patients experience an improved quality of life
  • If untreated, BPH is likely to progress and increase the risk of complications

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