Enlarged Prostate

What is an enlarged prostate?

The prostate is a small gland, usually about the size of a walnut, that is situated just below the bladder and above the penis.[1] The urethra passes through the prostate, which produces fluid that is mixed with sperm to create semen. When the prostate enlarges, it places pressure on the bladder and the urethra, which can cause urinary problems.

The prostate is made up of four zones:[2]

  • Peripheral zone: The area most easily felt during the standard digital rectal exam and the zone from which prostate cancer tends to develop.
  • Transition zone: This surrounds the part of the urethra that passes through the prostate. It enlarges as men age, causing benign prostatic hyperplasia and consequent urinary symptoms.
  • Central zone
  • Anterior fibromuscular stroma

The prostate can become enlarged for a variety of reasons. The most common are:[3]

  • Prostatitis: Inflammation of the prostate that can occur in men of any age. There are several types of prostatitis, including infectious acute or chronic bacterial prostatitis, non-infectious chronic pelvic pain syndrome (CPPS) and asymptomatic inflammatory prostatitis, in which an affected person will not show any symptoms.
  • Benign prostate hyperplasia (BPH): A benign, non-cancerous enlargement of the prostate, usually found in men older than 50 years of age. ‘Hyperplasia’ means that the number of cells increases.
  • Prostate cancer: Cancer of the prostate, mostly originating in the peripheral zone. Prostate cancer can spread to other areas of the body.

Symptoms of an enlarged prostate

Because the prostate is positioned so close to the bladder, penis and rectum, most disorders which cause enlargement of the prostate share several basic symptoms. These include:[1][3][4][5][6]

  • Urgency, an urgent, at times uncontrollable, need to urinate, which may lead to incontinence if the person can’t make it to the bathroom in time
  • Trouble urinating
  • Frequent urination
  • Urinary hesitancy, i.e.slow start till urine streams out
  • Decreased stream of urine (weak flow)
  • Frequent need to urinate at night (nocturia)
  • Intermittent flow,i.e.stopping and starting
  • Leaking or dribbling urine.

In severe cases of an enlarged prostate, whatever the cause, urinary retention (being unable to completely empty the bladder) may also occur.

In addition, prostatitis may also have some or all of the following symptoms:[7]

  • Blood in urine (hematuria) or in semen
  • Pain in the penis and testicles
  • Burning or painful sensation during urination
  • Painful or difficult ejaculation
  • Urethral discharge
  • Pain and/or pressure in the rectum
  • Painful defecation (painful bowel movements)
  • Discomfort and/or pain in the genitals, groin, lower back and/or lower abdomen
  • Recurring urinary tract infections (UTIs)
  • Sexual problems and loss of sex drive
  • Postcoital pain (pain after having sex).

In the case of prostate cancer, there may be no immediate symptoms, or there may be urinary symptoms like those listed above. In addition, there may be symptoms such as:

  • Hematuria (blood in the urine) or blood in semen
  • New onset of erectile dysfunction
  • Back,especially lower back, hip or pelvic pain
  • Unexplained weight loss

It should be noted that a lot of the urinary symptoms above could also be caused by diabetes or may be related to the use of certain medications. If any of these symptoms are detected, it is of paramount importance that a physician is consulted and the cause diagnosed, so that appropriate next steps can be taken.

Causes of enlarged prostate

A variety of different conditions and biological processes can cause the prostate to become enlarged. These include:

Prostatitis

Prostatitis is the painful inflammation of the prostate and can affect men of any age. There are several types of prostatitis:[8]

  • Chronic bacterial prostatitis
  • Acute bacterial prostatitis
  • Chronic Pelvic Pain Syndrome
  • Asymptomatic inflammatory prostatitis

Chronic bacterial prostatitis, the most common type of prostatitis, can affect all adult men and sometimes accompanies recurring urinary tract infections.[9] It can occur when bacteria from the bowel transfer to the skin, to the urethra and then up into the urinary tract. Another cause is urinary retention, caused by an enlarged prostate, bladder or kidney stones, causing a urinary tract infection that then spreads to the prostate.

Factors that put individuals at risk of prostatitis, other than UTIs, include prostate surgery or any complications of prostate surgery, catheterisation (using a thin, flexible tube called a catheter to drain urine from the bladder, e.g. when healing after surgery), and infections spreading from other parts of the body. For prostatitis to be considered chronic, symptoms have to recur for at least three months. Recurrence is possible because the prostate can harbor infection. Symptoms can come and go. Chronic prostatitis tends not to cause fevers.

Acute prostatitis is caused by infection and manifests with chills, fever and muscle pain, in addition to the multitude of urinary symptoms mentioned above ,often along with cloudy-appearing urine. It often causes intense/severe abdominal and/or pelvic pain. It is relatively rare compared to chronic prostatitis, but must be treated promptly. Complications can include developing a prostate abscess and also urinary retention, where the patient is unable to pass urine due to pain, and which requires catheterisation. A prostate abscess requires surgical intervention.[8]

Chronic Pelvic Pain Syndrome can cause persistent discomfort and/or pain in the lower pelvic region, mainly around the anus and the base of the penis. The causes of CPPS are not well understood and may involve autoimmune responses, nerve problems, inflammation, or another, yet unidentified cause.

In asymptomatic inflammatory prostatitis, there are no symptoms. The condition is usually diagnosed in the course of a prostate examination for other conditions or as part of a urologic routine check-up. It can cause elevated PSA-values - this is an enzyme produced by the prostate, often looked at during routine urologic check-ups of men over 50 and which can be detected in the blood.

Prostatitis is not a sexually-transmitted infection, although it can be caused by one. Prostatitis itself cannot be passed on via sexual activity, but sexually-transmitted infections that cause prostatitis can be. Prostatitis is not prostate cancer, and there is currently no evidence to suggest that getting prostatitis increases the risk of prostate cancer.[8]

Benign prostatic hyperplasia (BPH)

Benign prostatic hyperplasia is a common problem affecting men over the age of forty. By the time men turn 50 or older, an average of 40% have BPH to some degree. In BPH, the transition zone of the prostate enlarges, constricting the urethra, hindering, in some cases, the bladder’s ability to empty by throttling the flow of urine, which would normally move through the urethra and out of the bladder.

Benign Prostatic Hyperplasia is not cancer, but it can affect a person’s quality of life due to the urinary problems it causes, especially the increased need to urinate at night, which disrupts sleep. If left untreated, BPH can cause complications such as kidney damage, urinary retention (the bladder not fully emptying anymore), bladder or kidney stones and UTIs, all due to disrupted urination. As it is largely an age-related disorder, BPH can worsen as it progresses, if left unaddressed.

For more information, see this resource on BPH »


  1. NHS Choices. “Prostatitis” 3 March 2017. Accessed 13 February.

  2. Canadian Cancer Society. “The prostate”. Accessed 13 February 2018.

  3. Prostate Cancer UK. “Enlarged prostate”. December 2017. Accessed 15 February 2018.

  4. University of California Los Angeles Health “Conditions treated: definition of BPH (enlarged prostate)”. Accessed 12 February 2018.

  5. Laurence Knott. “Prostate Gland Enlargement”. 12 October 2015. Accessed 12 February 2018.

  6. Cancer Research UK. “Enlarged prostate”. December 2017. Accessed 15 February 2018.

  7. Canadian Cancer Society.“Prostatitis”. Accessed 13 February 2018.

  8. Laurence Knott. “Chronic Prostatitis”. 29 June 2015. Accessed 12 February 2018.

  9. Laurence Knott. “Acute prostatitis”. 19 June 2015. Accessed 12 February 2018.