Benign prostatic hyperplasia (BPH is a benign adenomatous overgrowth of the prostate gland. It is a common condition that affects 50% of men over the age of 50 years old. However, only 30% of men with BPH are symptomatic. It presents with lower urinary tract symptoms (LUTS) which 15-30% of men over the age of 65 years old will deal with regardless of having BPH or not.
Hyperplasia refers to an increase in the number of cells (while hypertrophy refers to the increase in cell size).
🦴 Anatomy and physiology
Let’s quickly recap the prostate gland:
The prostate gland is located between the bladder and the base of the penis. It is a walnut sized accessory gland that envelopes the prostatic urethra.
There are 4 main zones of the prostate to be aware of:
- Anterior fibromuscular zone - found anteriorly and is made of irregular connective tissue and smooth muscle.
- Peripheral zone - found in the lateral sections of the prostate and makes up 70% of the glandular tissue (it is also the main area where prostatic cancer arises).
- Central zone - found centrally and surrounds the ejaculatory ducts that enter the prostate. It makes up 25% of the glandular tissue of the prostate.
- Transitional zone - this surrounds the prostatic urethra. It contains mucosal glands and is also the main site for BPH to occur.
It has 4 major functions in the body:
- Penile erection - following physical or psychological stimulation the prostatic nerve plexus (S2-S4) of the parasympathetic nervous system kicks in and closes off the arteriovenous anastomoses of the penis which then redirects blood into the sinuses of the corpora cavernosa → erection.
- Sexual stimulation - the prostate is the erogenous zone (the “P-spot”) in the male anatomy and it is highly responsive to sexual stimulation and aids the ejaculatory response.
- 5-alpha reductase (5-AR) - this enzyme is produced in the prostate. Its function is to convert testosterone → dihydrotestosterone (DHT) which is 10x more potent than testosterone due to its higher affinity for the androgen receptor.
- Prostatic fluid - prostatic fluid is a milky and acidic fluid (pH of 6.5) that makes up 25% of semen. It aids sperm motility and nourishment. It is produced in the glandular regions of the prostate and enters the urethra via the prostatic ductules.
Pathophysiology
The exact mechanisms behind BPH are not entirely understood. The enlargement occurs as individuals get older. The reason for this is believed to be due to 3 factors that occur with ageing:
- Shifts in age-related hormonal changes - imbalances between androgen and oestrogen as time progresses leads to hyperplasia of the prostate. Androgens decrease while oestrogen play a greater role. Oestrogen increases cell proliferation and decreases cell death.
- Alterations in prostatic stromal-epithelial interactions
- Increase in prostatic stem cell numbers
Enlargement of the prostate leads to bladder outlet obstruction as a result of:
- Increased epithelial tissue in the transitional zone → a narrower urethra.
- Increased prostatic smooth muscle tone → impaired urethral widening.
⚠️ Risk factors
- ⭐️ Increasing age (especially over 50 years)
- Family history of BPH
- Cigarette smoking
- Male pattern baldness
😷 Presentation
As mentioned in the beginning, BPH is often asymptomatic. However, if it does present it is most commonly with lower urinary tract symptoms (LUTS).
LUTS can be divided into 2 types of symptoms - voiding symptoms and storage symptoms:
Voiding LUTS - problems relating to bladder outlet obstruction that make it more difficult to pass urine.
- Weak stream
- Hesitancy - delayed urine flow despite feeling the urge to urinate
- Intermittency - this is when the flow starts and stops and varies in its flow rate.
- Incomplete emptying - the inability to fully empty the bladder leading to chronic retention of urine.
- Straining
Storage LUTS - problems relating to the bladder not storing urine properly when it should be.
- Frequency - this is the need to pass urine often (usually in small amounts)
- Urge incontinence - a sudden urge to go to the toilet that cannot be delayed.
- Nocturnal enuresis - involuntary bed-wetting at night.
- Nocturia - waking up to urinate at night.
- Dribbling - commonly post-micturition.
Less commonly, patients may present with haematuria or haematspermia (presence of blood in semen). These are more concerning and require further investigations.
🔍 Investigations
Men presenting with LUTS need to be assessed with the following:
- Digital rectal examination - this physical examination allows assessment of the size, shape and characteristics of the prostate gland. BPH should feel smooth, symmetrical, slightly compressible with a maintained central sulcus.
- Abdominal examination - to assess for a palpable bladder or any other abnormalities.
- Urinary frequency volume chart - this records 3 or more days of fluid intake and urine output.
- Urine dipstick - to assess for UTI or haematuria (which is a red flag symptom).
- U&Es - especially if there is suspicion of chronic retention (suggested by bedwetting or an enlarged bladder detected on abdominal palpation or percussion).
- Prostate-specific antigen (PSA) - this is a protein produced by both normal as well as malignant cells of the prostate. It is mainly used to assess for prostatic cancer but it is an unreliable marker. The need for the test should be considered with patient preference in mind. False positives may lead to further investigations and invasive tests which may prove unnecessary and cause complications. False negatives may also be present that can lead to false reassurance.
What causes a raised PSA?
- Prostate cancer
- BPH
- Prostatitis
- UTI
- Vigorous exercise (especially cycling) in the past 48 hours.
- Recent ejaculation or prostate stimulation in the past 48 hours.
- Prostate biopsy in the past 6 weeks.
If the diagnosis is not certain still we may consider:
- Ultrasound of the renal tract - to calculate the volume of the prostate as well as assess the rest of the renal tract for causes of urinary retention or hydronephrosis.
- Urodynamic studies - this provides information on the bladder contractility, flow rate, storage capacity and to assess any issues with voiding.
🔢 Classification
We can classify the severity of LUTS symptoms using the International Prostate Symptom Score (IPSS). It is a self-administered patient questionnaire that assesses the severity of LUTS symptoms by quantifying their impact on the patient’s life:
- 0-7 - mild symptoms
- 8-19 - moderate symptoms
- 20-40 - severe symptoms
🧰 Management
For an incidental finding of BPH or with asymptomatic patients, we should simply reassure them and offer lifestyle advice (such as counselling on alcohol and caffeine intake as they promote urination, as well as pelvic floor and bladder training). We should also ask the patient to keep a symptom diary. A medication review should also be done as certain drugs can cause LUTS (such as antimuscarinics, tricyclic antidepressants, zolpidem).
Let’s look at how to treat symptomatic BPH:
- 🥇 Alpha-1-adrenergic receptor antagonists (alpha-blockers) (tamsuolosin, alfuzosin) - they work by relaxing the smooth prostatic smooth muscle tone to enable voiding and reducing the LUTS.
Adverse effects: postural hypotension (as a1-ARs are found in smooth muscle of vessels to produce vasoconstriction), priapism.
- 🥈 5-alpha reductase inhibitors (5-ARIs) (finasteride, dutasteride) - prostatic glandular tissue is highly receptive to DHT which binds to androgenic receptors to trigger the transcription of growth factors and promote prostatic proliferation. By inhibiting 5-AR we inhibit the conversion of testosterone → DHT thus resulting in less proliferation and gradual reduction in the size of the prostate. It takes up to 6 months of treatment to improve symptoms, however.
Adverse effects: decreased libido, decreased amount of semen.
🥉 If neither of these work, the third-line option is to use both an alpha blocker + 5-ARI together.
We should consider adding an antimuscarinic agent if the patient has a mixed picture (voiding + storage issues) and not responding to an alpha-blocker alone.
- 🥇 Alpha-blocker - such as tamsulosin or alfuzosin.
- 🥈 Alpha-blocker + antimuscarinic - the main antimuscarinic used is oxybutynin. However agents such as tolterodine or darifenacin may be used too.
Surgical management is only indicated if conservative management has failed.
The options include:
- 🥇 Transurethral resection of the prostate (TURP) - this is the most common surgical option. It involves removal of a portion of the prostate via the urethra. A resectoscope is inserted into the urethra and using a diathermy loop, portion of the prostate is removed. By doing so it expands the space to allow urine to flow and thus removing the LUTS.
- Bleeding
- Infection
- Urinary incontinence
- Erectile dysfunction
- Retrograde ejaculation
- Urethral strictures
- Failure to resolve LUTS
- TURP syndrome (more on this at the end).
It is a procedure that has carries the risk of many complications, such as:
- Transurethral electrovaporisation of the prostate (TEVAP/TUVP) - this involves insertion of a resectoscope with a rollerball electrode attached that rolls across the prostate and vaporises prostatic tissue.
- Holmium laser enucleation of the prostate (HoLEP) - a resectoscope with a laser is inserted into the urethra and the laser then removes prostatic tissue.
- Open prostatectomy - this is done via an abdominal or perineal incision. It carries greater risk of complications and has a longer recovery period as compared to the other procedures.
🚨 Complications
TURP using monopolar energy requires hypoosmolar irrigation during the procedure . Hypoosmolar solutions get absorbed into the bloodstream which can then lead to fluid overload and dilutional hyponatraemia as fluid enters the circulation through the open venous beds that are exposed during the surgery.
Fortunately due to the use of bipolar energy and isotonic irrigation this is not seen as much nowadays.
😷 Presentation
- Headaches
- Confusion, convulsions coma
- Nausea
- Agitation
- Visual changes
- Neurological issues - if glycine 1.5% is used as the irrigating agent. Glycine is an inhibitory agent that acts on GABA receptors in the CNS.
- Respiratory distress and pulmonary oedema
- Arrhythmias
🧰 Management
The management involves reduction of fluid overload and correction of hyponatraemia that occurs with the haemodilution.
- IV furosemide
- Hypertonic saline - this must be used to correct the sodium slowly (no more than 10-12mmol/24 hours) as rapid correction of hyponatraemia can lead to fatal brain herniation.
Other complications include:
- UTI
- Renal failure
- Bladder stones
- Haematuria
- Erectile dysfunction
- Urinary retention
- Overactive bladder