Benign Prostatic Hyperplasia

Study guide:

Definition:
Benign prostatic hyperplasia is nonmalignant adenomatous overgrowth of the periurethral (transitional/central zone) prostate gland.

Epidemiology:

  • Affects ~ 70% by age 60 and surpasses 90% by age 80.

  • Family history of first degree relative is found in 90% of the cases.

  • Moderate to severe symptoms occur in about a third of the patients.

  • The prostate increases in volume by 2.4 cm3 per year on average from
    40 years of age.

Pathophysiology:

  • Pathophysiology is not well understood yet.

  •  Men castrated before puberty do not develop BPH when they age, supporting the androgen theory.

  • Excessive androgen → overgrowth of both stromal and glandular elements.

  • DHT (synthesized in the stromal cells) plays a major role → Stromal cells predominates the hyperplasia → occurs in the periurethral lobes (lateral and median lobes)→ Compression of the urethra → Bladder outflow obstruction →Lower urinary tract symptoms.

  • Increased sensitivity to DHT!

  • Activation of α1-adrenergic receptors of the prostate and bladder → smooth muscle contraction → further exacerbation of obstruction clinical symptoms.

  • Benign prostatic hyperplasia does not progress to prostate cancer. 

Clinical Presentation:

  • Lower urinary tract symptoms:

    • Related to storage:

      •  Frequency.

      •  Noctouria.

      •  Dysuria.

      •  Urgency.

      •  Urge 

      •  incontinence.​​

  • Related to voiding:

    • Hesitancy.

    • Weak stream.

    • Intermittency.

    • Straining.

    • Post void dribbling.​

Diagnosis:

  • International Prostate Symptoms Score: A score used to assess the symptoms and quality of life

  • Digital rectal exam: This will reveal an enlarged prostate : Smooth, firm, and diffuse enlargement of prostate.

  • Transrectal ultrasonography (TRUS): Not indicated for the initial evaluation of uncomplicated LUTS, used to assess the size of the prostate.

  • Urodynamics: Useful for objective assessment of obstruction. 

  • Blood test:

    • Prostate specific antigen (PSA): To screen for prostate cancer, BPH does not cause prostate cancer, but men at risk of BPH are also at risk of cancer (in BPH it is usually <10 ng/mL).

    • BUN, electrolytes, and creatinine: Not routinely done, useful to assess renal function in patients who have high postvoid residual (palpable bladder), nocturnal enuresis, recurrent UTI or a history of renal stones.

  • Urinalysis & Urine cultures: To rule out infections and hematuria.

Management:

  • Lifestyle modification: Decrease caffeine and alcohol intake, decrease water consumption before bedtime.

  • Watchful waiting: Used for patients with mild to moderate symptoms.

  • Medications:

    • Non-selective α1 receptor blockers (terazosin): 

      • MOA: Relaxes smooth muscle in the prostate and bladder neck, opposing α1-adrenoceptor-mediated prostatic growth, relieving the symptoms of obstruction. It also blocks the α1-B receptor blockers on blood vessels.

      • SE: Postural hypotension in normotensive patients, headache, and nasal congestion.

    • Selective α1-A receptor blockers (tamsulosin): 

      • MOA: used in normotensive patients as its mechanism of action is to block the α1-A receptors in the smooth muscles of the prostate and bladder and not the receptors on the smooth muscles of blood vessels, and thus not causing postural hypotension. 

    • 5α-reductase inhibitors: 

      • MOA: Inhibits the conversion of testosterone to DHT (which has higher affinity in the prostate).

      • SE: Decreased libido, erectile dysfunction, and gynecomastia.

  • Surgical (reserved for patients with severe symptoms recalcitrant to medication):

    • Transurethral resection of prostate (TURP).

    • Holmium laser enucleation.

    • Open prostatectomy.

Complications

  • Recurrent Urinary tract infection: The presence of residual urine in the bladder due to chronic obstruction increases the risk.

  • Hydronephrosis: Severe BPH leads to complete urinary obstruction, with resultant painful distention of the bladder, if untreated could lead to hydronephrosis and postrenal failure.

References:

Written by:         Lama Al Luhidan

Reviewed by:     Bassam AlGhamdi

                            Roaa Amer ​

Format editor:   Adel Yasky

Audio recording:

Read by: Bayan Alzomili

Directed by: Rana Alzahrani 

Audio production: Bayan Alzomaili

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