Enlarged Prostate - Causes
Acute (severe) infectious prostatitis: This may be caused by a bacteria or virus.
Chronic (long-lasting) infectious prostatitis: This also may be caused by a bacteria. Stress, caffeine, nicotine, or alcohol may worsen the condition.
Noninfectious prostatitis: This form of prostatitis is not caused by a bacteria and therefore antibiotics are not helpful. This is the most common type of prostatitis. It may be exacerbated by stress and/or irregular sexual activity. Stress may cause the pelvis muscles to tighten and cause pain. Increased pressure during voiding may cause urine to back up into the ducts resulting in a form of chemical prostatitis. The prostate gland produces fluid for semen and infrequent ejaculation may cause the ducts to become clogged with secretions.
Two conditions are necessary for the development of BPH; namely, aging and the presence of testes. It is well known that human males who are castrated prior to the time of puberty never develop BPH. Benign prostatic hyperplasia (BPH) is a common but incompletely understood consequence of aging.
That an enlarging prostate and the development of LUTS (lower urinary tract symptoms) are both age dependent is indisputable. Autopsy studies have demonstrated that up to 80% of 80-year-old men will have historic evidence of BPH. Approximately 40% of those same men will demonstrate an enlarged prostate on physical examination; however, only 25-30% of 80 year old men will have symptomatic BPH and pursue treatment.
The development of BPH requires the presence of testosterone. The cascade of hormonal events leading to this phenomenon begins with the release of luteinizing-releasing hormone (LHRH) by the hypothalamus. LHRH acts on the anterior pituitary gland to stimulate the production of luteinizing hormone (LH). LH circulates in the bloodstream and induces the testicular Leydig cells to produce testosterone. Testosterone, in turn, acts on individual prostatic epithelial cells where it binds at the cell membrane with a surface receptor and is a substrate for the enzyme 5a -reductase. The primary product of 5a -reductase activity on testosterone is the metabolite, 5a -dihydrotestosterone (DHT). DHT binds with a receptor in the cytosol and becomes a hormone-receptor complex which is then transported to the nucleus. It is DHT which seems to be critical for the development of BPH.
Bladder Outlet Obstruction
The most common cause of a bladder outlet obstruction is an enlarged prostate. Additional causes include can include prostate cancer, narrowing of the urethra or bladder outlet scarring from infection, injury or surgery or bladder stones. Bladder outlet obstruction may also occur as a side effect of certain medications, such as antihistamines and decongestants.
Once bladder outlet obstruction has been confidently diagnosed it is helpful to think of this concept as being attributable to both static and dynamic factors. The static component of bladder outlet obstruction may be attributed to the physical enlargement of the prostate as it encroaches on the prostatic urethra and bladder outlet. The dynamic portion of the obstruction is more likely related to the relative tension of prostatic and bladder neck smooth muscle. It is particularly useful when formulating a strategy for the treatment of bladder outlet obstruction to consider whether the detrusor itself is intact. A variety of conditions, most notably diabetes mellitus, may result in a detrusor muscle that is ineffective in generating pressures high enough to overcome even normal resistance at the bladder outlet.