As the prostate enlarges, it starts to press against the urethra and the bladder (see Figure below), like a foot stepping on a garden hose or fingers pinching a straw. This pressure eventually obstructs the flow of urine, forcing the bladder to squeeze harder to push urine through the urethra. But straining to urinate, although unavoidable, only makes matters worse. Like any muscle, the bladder wall becomes thicker with work. That thickness reduces the amount of urine the bladder can hold and causes it to contract even when it contains only small amounts of urine, causing more frequent urination. Eventually, the bladder can become so bulked up that it loses its elasticity and can no longer empty itself.
The narrowing of the urethra and partial emptying of the bladder cause many of the problems associated with BPH. You may feel as though you have to urinate immediately, yet have to strain to do so. You may have a weak urinary stream or one that stops and starts. You may dribble after urinating or feel as if you’re not emptying your bladder completely. And you may feel the need to urinate frequently—even every few minutes; at night, the continual need to go to the bathroom can make it impossible to sleep well, causing all sorts of negative health consequences. Some men also experience urinary inconti-nence,the involuntary discharge of urine.
As the prostate gland enlarges, it constricts the urethra, the tube that carries urine out of the body, and impedes urine flow. The bladder has to work harder to force stored urine out. Over time, the bladder walls thicken, leaving less room for urine.
How large the prostate gets and the symptoms that BPH causes vary from one man to the next. In some cases, the prostate reaches a certain size, and the symptoms plateau at a mild level and never worsen. In others, the prostate may continue to enlarge, but as it does, it grows away from the urethra,so it doesn’t cause additional impingement.
Particularly in the early years of the condition, the symptoms may ease up before getting worse again. But in some men, the disease progresses, and the symptoms intensify stead-ily, year after year. In extreme cases, the prostate, normally walnut- sized, can grow as large as an orange.
Most physicians advise against medical or surgical treatment for men with mild symptoms because the side effects of the treatment outweigh the potential benefits. But if the symp-toms worsen, ordinary activities may become a challenge. A man may find it hard to sit through a lengthy meeting. Aisle seats become a necessity so there’s a quick escape to the bathroom. Many men wear absorbent pads or limit themselves to dark clothing to conceal their incontinence.
BPH can also result in some serious complications. If an enlarged prostate keeps your bladder from emptying completely, you may be vulnerable to frequent urinary tract infections. The risk of developing bladder stones increases. A growing prostate can rupture blood vessels in the urethra, causing blood to appear in the urine. A thorough medical evaluation is necessary any time there’s blood in the urine.
If obstructive BPH goes untreated for too long, the bladder may get stretched out, causing the muscular part of the wall to weaken. Your bladder may not have enough power to push urine past the obstructing prostate gland, a condition known as acute urinary retention. The bladder may become so stretched out that urine cannot adequately empty from the kidneys. In the worst cases, this can lead to kidney failure.
Not being able to urinate at all is painful and a true medical emergency, requiring the tem-porary passage of a catheter (a thin tube) through the urethra to allow the bladder to drain. Fortunately, such complications are uncommon because most men seek medical attention well before serious problems develop.