also called prostate enlargement, is a noncancerous increase in size of the prostate.
Symptoms may include frequent urination, trouble starting to urinate, weak stream, inability to urinate, or loss of bladder control.
Complications can include urinary tract infections, bladder stones, and chronic kidney problems.
The cause is unclear.
Risk factors include a family history, obesity, type 2 diabetes, not enough exercise, and erectile dysfunction.
Medications like pseudoephedrine, anticholinergics, and calcium channel blockers may worsen symptoms.
The underlying mechanism involves the prostate pressing on the urethra thereby making it difficult to pass urine out of the bladder.
Diagnosis is typically based on symptoms and examination after ruling out other possible causes.
Treatment options including lifestyle changes, medications, a number of procedures, and surgery.
In those with mild symptoms weight loss, exercise, and decreasing caffeine intake is recommended.
In those with more significant symptoms medications may include alpha blockers such as terazosin or 5α-reductase inhibitors such as finasteride.
Surgical removal of part of the prostate may be carried out in those who do not improve with other measures.
Alternative medicine, such as saw palmetto, does not appear to help.
About 105 million people are affected globally.
BPH typically begins after the age of 40.
Half of males age 50 and over are affected.
After the age of 80 about 90% of males are affected.
Although Prostate Specific Antigen (PSA) levels may be elevated in males with BPH,
the condition does not increase the risk of prostate cancer.
Most experts consider androgens (testosterone and related hormones) to play a permissive role in the development of BPH.
This means that androgens must be present for BPH to occur, but do not necessarily directly cause the condition.
This is supported by evidence suggesting that castrated boys do not develop BPH when they age.
In an unusual study of 26 eunuchs from the palace of the Qing dynasty still living in Beijing in 1960,
the prostate could not be felt in 81% of the studied eunuchs.
The average time since castration was 54 years (range, 41–65 years).
On the other hand, some studies suggest that administering exogenous testosterone
is not associated with a significant increase in the risk of BPH symptoms,
so the role of testosterone in prostate cancer and BPH is still unclear.
Further randomized controlled trials with more participants are needed to quantify any risk of giving exogenous testosterone.
Dihydrotestosterone (DHT), a metabolite of testosterone, is a critical mediator of prostatic growth.
DHT is synthesized in the prostate from circulating testosterone by the action of the enzyme 5α-reductase, type 2.
DHT is ten times more potent than testosterone because it dissociates from the androgen receptor more slowly.
Testosterone promotes prostate cell proliferation,[18] but relatively low levels of serum testosterone are found in patients with BPH.
While there is some evidence that estrogen may play a role in the cause of BPH,
this effect appears to be mediated mainly through local conversion of androgens to estrogen in the prostate tissue rather than a direct effect of estrogen itself.
In canine in vivo studies castration, which significantly reduced androgen levels but left estrogen levels unchanged, caused significant atrophy of the prostate.
Studies looking for a correlation between prostatic hyperplasia and serum estrogen levels in humans have generally shown none.
Studies from China suggest that greater (animal?) protein intake may be a factor in development of BPH.
Men older than 60 in rural areas had very low rates of clinical BPH,
while men living in cities and consuming more animal protein had a higher incidence.
On the other hand, a study in Japanese-American men in Hawaii found a strong negative association with alcohol intake,
but a weak positive association with beef intake.
In a large prospective cohort study in the US (the Health Professionals Follow-up Study),
investigators reported modest associations between BPH
(men with strong symptoms of BPH or surgically confirmed BPH)
and total energy and protein, but not fat intake.
There is also epidemiological evidence linking BPH with metabolic syndrome
(concurrent obesity, impaired glucose metabolism and diabetes, high triglyceride levels, high levels of low-density cholesterol, and hypertension).
The clinical diagnosis of BPH is based on a history of LUTS (Lower Urinary Tract Symptoms)
and a digital rectal exam.
Urinalysis is typically performed when LUTS are present
and BPH is suspected to evaluate for signs of a urinary tract infection,
glucose in the urine (suggestive of diabetes),
or protein in the urine (suggestive of kidney disease).
Bloodwork including kidney function tests and prostate specific antigen (PSA)
are often ordered to evaluate for kidney damage and prostate cancer, respectively.
However, checking blood PSA levels for prostate cancer screening is controversial
and not necessarily indicated in every evaluation for BPH.
Benign prostatic hyperplasia and prostate cancer are both capable of increasing blood PSA levels
and PSA elevation is unable to differentiate these two conditions well.
If PSA levels are checked and are high, then further investigation is warranted.
Measures including PSA density, free PSA, rectal examination, and transrectal ultrasonography
may be helpful in determining whether a PSA increase is due to BPH or prostate cancer.
Ultrasound examination of the testes, prostate, and kidneys is often performed,
again to rule out cancer and hydronephrosis.
Lifestyle alterations to address the symptoms of BPH include physical activity,
decreasing fluid intake before bedtime,
moderating the consumption of alcohol and caffeine-containing products
and following a timed voiding schedule.
Voiding position
Voiding position when urinating may influence urodynamic parameters
(urinary flow rate, voiding time, and post-void residual volume).
A meta-analysis found no differences between the standing and sitting positions for healthy males,
but that, for elderly males with lower urinary tract symptoms, voiding in the sitting position:
- decreased the post void residual volume
- increased the maximum urinary flow, comparable with pharmacological intervention
- decreased the voiding time
This urodynamic profile is associated with a lower risk of urologic complications, such as cystitis and bladder stones.
The two main medication classes for BPH management are:
- alpha blockers
Alpha blockers relax smooth muscle in the prostate and the bladder neck, thus decreasing the blockage of urine flow.
Common side effects of alpha blockers include orthostatic hypotension (a head rush or dizzy spell when standing up or stretching),
ejaculation changes, erectile dysfunction, headaches, nasal congestion, and weakness.
- 5α-reductase inhibitors.
These medications inhibit the 5α-reductase enzyme, which, in turn,
inhibits production of DHT, a hormone responsible for enlarging the prostate.
Effects may take longer to appear than alpha blockers, but they persist for many years.
If medical treatment is not effective a person may try office-based therapies
or transurethral resection of prostate (TURP),
surgery may need to be performed.
Surgical techniques used include the following:
- Transurethral resection of the prostate (TURP): the gold standard.
- Photoselective (laser) vaporization of the prostate (PVP): common treatment.
- Open prostatectomy: not usually performed nowadays, even if results are very good.
- Transurethral incision of the prostate (TUIP): rarely performed; the technique is similar to TURP but less definitive.