The prostate is a gland found in men that is located at the base of the bladder. Its function is to secrete fluid that makes up part of the semen (sperm fluid). The prostate wraps around the urethra, which is the canal in the penis that drains urine from the bladder. In young men, the prostate is about the size of a walnut. As men get older, the prostate also becomes enlarged.

This process is called benign prostatic hyperplasia (BPH) – or benign (non-cancerous) enlargement of the prostate. As such, the prostate can cause compression of the urethra at that level, resulting in bladder symptoms.

Benign Prostatic Hyperplasia Anatomy

How common is BPH?

BPH-related bladder symptoms are very common. It is estimated that about 40% of men over the age of 65 will suffer from them. This can significantly impact a person’s quality of life. The prevalence increases with age. Other factors that may increase the risk of BPH are race, environment, diet, and genetics. BPH is more common in Western societies compared to Asian. It is less common in those who eat large amounts of vegetables. It also seems to run in the family, and the incidence increases if a first-degree relative (father or brother) has it.

What are the symptoms of BPH?

Bladder symptoms associated with prostatic enlargement are called lower urinary tract symptoms (LUTS). This can be divided into two main groups – voiding symptoms and storage symptoms. The voiding symptoms are caused by the obstruction from the enlarged prostate. When this happens, the bladder can become overactive (see overactive bladder) secondary to the obstruction and result in storage symptoms. Late stages of untreated BPH can cause the bladder to ‘give up’ and become underactive.

Voiding symptoms

  • Needing to wait for the stream to start (hesitancy).
  • Weak stream.
  • The stream starts and stops intermittently.
  • Having to push and strain to pass urine.
  • Dribbling at the end of urination.
  • The sensation of incomplete bladder emptying.

Storage symptoms

  • Frequent visits to the toilet to pass urine.
  • Having a strong need to void that cannot be deferred (urgency).
  • Waking up at night to pass urine (nocturia) – see night-time symptoms.
  • Leakage of urine when one does not get to the toilet in time (urge incontinence).

The International Prostate Symptom Score (IPSS) is a validated short questionnaire that is very useful in determining how severe a patient’s bladder symptoms are. A score of 0 – 7 indicates mild symptoms, 8 – 19 indicates moderate symptoms and 20 – 35 indicates severe symptoms.

In advanced cases, BPH can also cause more complicated symptoms. They are:

  • Acute urinary retention:
    • The patient blocks up completely and cannot pass urine. A urinary catheter must be inserted to drain the bladder.
  • Blood in the urine (haematuria):
    • An enlarged prostate often has engorged vessels that can bleed into the bladder and get mixed in with the urine. This can be precipitated by straining (e.g., constipation) or being on blood-thinning medications. This is often scary and alarming for the patient. If severe, a patient would have to be admitted for continuous bladder washout (a closed catheter system that allows fluid to be trickled into the bladder and drained at the same time – this can stop further bleeding in the urine).
  • Kidney damage from bladder obstruction (obstructive uropathy):
    • Blockage at the bladder outlet can result in a distended bladder that can cause back-pressure of urine up the ureters (tubes that drain the kidneys to the bladder) and kidneys. This can cause kidney damage and is potentially dangerous.
  • Chronic urinary retention:
    • If a patient has experienced prostate-related bladder problems for a long time, the bladder will eventually overstretch, resulting in its inability to completely empty itself (see underactive bladder). This means that there will always be some urine left behind after each void, and this residual urine can in turn form bladder stones or urinary tract infections. It can also cause continuous leakage of urine called overflow incontinence.

What is PSA?

Prostate-specific antigen (PSA) is an enzyme secreted by prostate cells that liquefies semen to allow sperm to swim freely. PSA is present in the blood at low levels in men with healthy prostates but is elevated in men with prostate cancer or other prostate disorders. PSA testing is useful for detecting prostate cancer, but other non-cancer conditions (such as BPH) can also increase levels. The estimated PSA increase is 0.3 ng/mL per gram of BPH tissue.

What will happen if BPH is not treated?

BPH is a disease that progresses slowly. The average increase in prostate volume is 1 – 2 cc / year. In men with mild symptoms, 57% worsen in 4 years; however, only 10% will require surgical intervention. In men with severe symptoms, 39% will undergo prostate surgery within 4 years.

Symptoms at initial diagnosis

Symptoms 4 years after diagnosis
























The risk of BPH progression is higher in men with older age, more severe symptoms, larger prostate size, and higher PSA.

What other prostatic conditions can cause bladder symptoms?

Other things that the prostate may develop are infection or swelling (prostatitis) and prostate cancer.


Prostatitis can also cause bladder symptoms as well as a deep-seated discomfort located in the area between the scrotum and the anus (perineum or where the prostate is located). This can generally be treated with antibiotics. Refractory cases may benefit from TURP surgery.

Prostate cancer

Prostate cancer often does not cause any symptoms. If the prostate is large enough, it can cause the same bladder symptoms as that of BPH.

How is BPH diagnosed?

Physical examination

After a careful history is obtained, a digital rectal examination (DRE) is performed. This involves a lubricated, gloved finger in the rectum, with the patient either lying on his left side all curled up or bent over in a standing position. DRE can tell us about the size, consistency, and symmetry of the prostate gland. The abdomen will also be palpated and the external genitalia examined.


The following investigations are useful when diagnosing BPH:

Urine test

A urine test should be done to rule out infection or bladder cancer, which can mimic the same symptoms as that of BPH. An infection can cause the PSA to rise.


PSA is an optional test in the investigation of BPH. In patients with a single, slightly raised PSA level, it is often difficult to distinguish between BPH and prostate cancer. PSA can provide a useful indication of prostate volume, which can then predict those who are most likely to experience BPH progression.

Urine flow rate and residual volume measurements

A patient is asked to void into a bucket that is electronically calibrated such that urinary flow parameters can be measured. It can measure the peak flow rate, average flow rate and volume voided. The pattern of the tracing of the flow rate is also clinically useful. The peak flow rate can indicate the degree of obstruction; with a voided volume of > 150ml, a peak flow rate of <15 ml/sec suggests obstruction. A peak flow rate of < 10 ml/sec suggests marked obstruction. However, it must be noted that an underactive bladder (one that does not contract strongly) can also cause a low peak flow rate.

The residual volume is measured with a bedside ultrasound probe, which is applied to the bladder area after a void. This is useful in determining whether a patient can empty his bladder well. Patients with a high residual volume are more likely to develop acute urinary retention and need surgery later on.


A formal ultrasound of the urinary tract is useful to measure the prostate volume, residual volume and exclude kidney obstruction and bladder stones.

Urodynamics (bladder function studies)

Urodynamics studies are not routinely done in the investigation of BPH. It is done when the diagnosis is unclear, or when a patient has not responded to an initial trial of oral medications. It can assess the degree of bladder obstruction, the presence of an overactive bladder, and how well the bladder can contract. This information can help decide if the patient will benefit from invasive surgery like a TURP (transurethral resection of the prostate).


cystoscopy (internal inspection of the bladder with a tube-like camera) is also an optional procedure in the investigation of BPH. It can look for other causes of obstruction including urethral strictures (scarring of the canal in the penis which drains the bladder), a tight bladder neck, or a bladder stone. It can also assess the degree of obstruction caused by the prostate; some small prostates may have a large internal median lobe that can cause obstruction. In the bladder, it can look for signs of obstruction like an overstretched bladder with diverticuli (outpouchings). If there is a history of blood in the urine, it can differentiate bleeding from the prostate vs. a bladder tumour.

What are the treatments?

Not all patients need treatment, especially if their symptoms are not too bothersome. As discussed above, about a third of patients with symptoms remain unchanged after 4 years. Therefore, observation is a reasonable option in patients with uncomplicated BPH.

In those who are more bothered, or those with complicated symptoms, medications or surgery can be offered.


There are a few classes of drugs that are useful for the treatment of BPH. In some patients, combination therapy with the drugs described below, may be more beneficial than single-drug therapy.

Alpha blockers (e.g., prazosin, tamsulosin, silodosin)

This is considered the first-line medical treatment for BPH. It gives the best results in terms of relieving obstruction. It acts by relaxing the bladder neck and the prostate.

Side effects include dizziness, tiredness, blocked nose, and retrograde ejaculation (semen going backwards into the bladder during ejaculation because of relaxation of the bladder neck).

5 alpha reductase inhibitors (e.g., dutasteride, a component of Duodart)

These drugs act by shrinking the prostate volume over time (about 3 to 6 months). They are not as effective in improving flow symptoms as alpha blockers, but they can reduce the risks of surgical intervention and acute urinary retention in men with large prostates. They can reduce prostatic bleeding too.

Side effects are erectile dysfunction, decreased sex drive, reduced ejaculate volume and rarely, breast enlargement.

Because these drugs reduce the PSA level by about half, a baseline PSA must be done prior to starting them.

Anticholinergics (e.g., oxybutynin, solifenacin, darifenacin)

These bladder-calming medications are useful in treating the storage symptoms associated with an overactive bladder secondary to obstruction. They do not help much with the voiding symptoms as described above.

Side effects include dry mouth, dry eyes, constipation, confusion, and urinary retention.

Beta 3 agonist (e.g., mirabegron)

This is an alternative to an anticholinergic and is effective in treating an overactive bladder. It is generally better tolerated with less side effects.


Phytotherapy (plant extracts e.g., saw palmetto, African plum) drugs are herbal medications that are widely available over the counter and in supermarkets. However, many trials have shown them to be no more effective than placebo. Therefore, these drugs are generally not recommended by urologists for the treatment of BPH.


In those who fail medication treatment or in those with advanced BPH, surgery may be indicated.

TURP (transurethral resection of the prostate) or prostate ‘reboring’

Transurethral resection of the prostate is done internally with no open cuts. A resecting loop is passed down a cystoscopic instrument with a camera and the prostate is excised in chips. This opens the passageway for the urine to flow through. About 90% of patients will find an improvement in their symptoms.

The classic method of resection is with diathermy (electric current). Techniques using laser (Green light laser TURP, Holmium laser) now have an increasing role, especially in those who are on blood thinners and cannot stop them for an operation.

It is performed under general or spinal anaesthesia. The operation time is about 40 – 60 minutes. The estimated length of stay in the hospital is 2 – 3 days.

Complications include ‘water intoxication’ from the absorption of fluid during the surgery, bleeding (transfusion rate about 2%), infection, incontinence (1%), erectile dysfunction (2 – 4%) and retrograde ejaculation (> 70%).

The prostate can regrow over time; about 10% to 15% of patients will need a revision-TURP within 10 years.

Bladder neck incision (BNI)

If the prostate gland itself is small and does not look too obstructive during cystoscopy and the reason for the obstruction is attributed to a tight bladder neck, a BNI procedure can be done.

This is also done internally with a cystoscopic instrument. It is effective in relieving symptoms and has lower complication rates than a TURP.


This involves the placement of small retractors or ‘stapling’ anchors to the inside of the prostate gland, pushing the gland laterally and thus opening the channel. No prostate tissue is removed. It is not suitable for larger size prostates, or those with a large median lobe of the prostate.

Other endoscopic treatments (e.g., Rezum water vapour treatment, microwave therapy)

Newer techniques are becoming available and may be suitable for certain individuals. An example is one that uses heat in water vapour to shrink the prostate. Some of these newer techniques do not have comparable long-term data yet, as other established ones, so a patient is advised to do his research accordingly.

Prostatic artery embolization

This is done by an interventional radiologist. The blood vessels supplying the prostate are identified with special X-rays done via a small catheter inserted into the artery of the wrist or groin. Small particles are then inserted to block off these blood vessels, with the aim of shrinking the prostate overtime.

This is still considered experimental in some centres with no long-term data yet. It is not suitable for everyone. Side effects include pain when passing urine, pelvic pain, nausea, vomiting, fever, blood in the urine, and infection.

Open simple prostatectomy

In men with very large prostates (> 100g), they run the risk of developing ‘water intoxication’ complications from a prolonged TURP operation (TURP syndrome).

In this case, the inner parts of the prostate gland are removed through a lower abdominal incision. It is also useful if the patient has a large bladder stone that needs removal at the same time.

It is more effective in relieving symptoms (98%) than a TURP, and the results are more durable.

However, there is a higher risk of needing a blood transfusion (<30%) and erectile dysfunction (19%) as compared to a TURP. There is a longer stay in the hospital too.


Occasionally, when a bladder has been obstructed for too long, it loses its ability to contract strongly. As such, a patient can develop chronic urinary retention, with incomplete emptying of the bladder. Sometimes, this can persist even after prostate surgery. The patient is then taught to either do intermittent self-catheterisation or to consider a long-term indwelling catheter (if frail).

Some patients may be too unwell to have an operation. A long-term catheter is then considered. This is changed every 6 weeks or so by a community nurse.