Benign Prostatic Hyperplasia (BPH)

Question 1

Background

Answer 1

Prostate - small heart shaped gland below the urinary bladder and in front of the rectum and surrounds the proximal urethra. Pea size (1g) at birth then grows at puberty (15-20g) Then at 40 yrs old 2nd growth spurt occurs and keeps growing till the rest of their life. Can go 4X in size or +.
Prostate gland made of epithelial tissue, stromal tissue (stromal-to-epithelial tissue ratio of 2:1) and the capsule.

Functions of prostate:
- Secret fluid that makes up part of semen
- Closes bladder and urethra opening during ejaculation - prevents mixing
- Provide secretions antibacterial effect

When enlarged ratio is 5:1.
Androgen can cause epithelial tissue growth. Stromal (smooth muscle) tissue and the capsule have Alpha1 adrenergic receptors. When stimulated by Noradrenaline (NA) these receptors makes them contract around the urethra = Reduction in urethra lumen = decreased bladder emptying CAN = LUTIs. Also in the capsule androgen is converted by 5a reductase to DHT (Dihydrotestosterone).

5a reductase types:
- Type 1 local to sebaceous glands in front scalp, liver, skin, small amount in prostate. DHT made here = acne and increased body/facial hair.
- Type 2 local to the prostate, genital tissue, and hair follicles of the scalp. DHT here = growth & enlargement of the prostate gland.

Oestrogen can also stimulate growth of stromal prostate. As men age serum Testosterone to oestrogen level decreases due to less production of testosterone and increased adipose tissue conversion of androgen to oestrogen.

BPH dont happen in castrated men before puberty or men with Type 2 5a reductase deficiency.

Question 2

Pathogenesis (origination/development of condition) of BPH

Answer 2

Can be from:
- STATIC factors = anatomic enlargement of the prostate gland, which produces a physical block at the bladder neck and thereby obstructs urinary outflow.
- DYNAMIC factors = to excessive α-adrenergic tone of the stromal prostate gland, bladder neck, and posterior urethra, which results in contraction of the prostate gland around the urethra and narrowing of the urethral lumen.

Drugs with significant anticholinergic AEs may decrease contractility.
Diuretics could solve urinary retention from obstructive prostate. diuretics induce polyuria.

Question 3

Signs and Symptoms

Answer 3

Obstructive:
poor flow, hesitancy, post-micturition dribble, sensation of incomplete emptying and occasional acute urine retention

Irritative:
frequency of urination, nocturia and urgency and urge incontinence

Symptoms can become better or worse over time. Some patients dont need treatment at all.

Question 4

Complications of BPH

Answer 4

Acute, painful urinary retention, can = acute renal failure.

Persistent gross haematuria when tissue growth >blood supply.

Overflow urinary incontinence or unstable bladder.

Recurrent UTI from urinary stasis.

Bladder diverticula.

Bladder stones.

Chronic renal failure from long time bladder outlet obstruction

Question 5

Assessment / Diagnosis

Answer 5

Should have a physical exam:
- Rectal/abdomen exam
- Digital rectal exam
- Ultrasound
Tests may be done:
- Serum PSA (1.4 ng/ml) (cut off point increases with age) - PSA is higher with benign prostate.
- Urinalysis - dipstick and send MSU
- Blood (U&E and creatinine, FBC, LFTs)

Question 6

Treatment

Answer 6

Behaviour mods:
- Restrict fluid intake close to bedtime
- Minimise caffeine and alcohol intake
- Frequent emptying of bladder in waking hours
- Avoid drugs that can worsen symptoms

Moderate to severe LUTs:
1st line - Alpha blocker
(Alfuzosin, doxazosin, tamsulosin, terazosin)
Can ADD anticholinergic (oxybutynin) if no response to above
ALT beta 3 agonist as add on

Prostate approx. >30cc or PSA>1.4:
5 ARi (finasteride, dutasteride)

Moderate to severe LUTs + prostate approx. >30cc or PSA>1.4.
Combo Alpha blocker + 5ARi (5alpha reductase inhibitor)

Overactive bladder:
Anticholinergic (oxybutynin, solifenacin, trospium)

Question 7

Basic moa/ Review

Answer 7

Alpha blocker - reduce the tone in the muscle of the neck of the bladder.

5ARi- block synthesis of DHT from testosterone and can reduce symptoms

Anticholinergic/ Antimuscarinic - competitively inhibit acetylcholine. They block M3 receptors - promotes bladder relaxation, increase in bladder capacity.

Review:
Asses symptoms/ effects/quality of life of treatment:
- Alpha blocker, Anticholinergic, beta 3 agonists = every 4-6 weeks THEN every 6-12 months
- 5 ARI- every 3-6 months THEN every 6-12 months

IF STILL NO RESPONSE REFER
possibly use surgery.