Читать книгу Saving Your Sex Life: A Guide for Men With Prostate Cancer - John P. Mulhall - Страница 16

In a boy, the prostate weighs about 5 gm and in a young man it grows to approximately 20 gm. Beyond the fourth decade in life, it is inevitable that the prostate will grow, and prostates have been removed which are in excess of 200 grams. Increase in size is due to increase in the size and number of the glands within the prostate itself. As the prostate grows, it impinges upon the urethra, which results in an obstruction of urine flow from the bladder. This leads to symptoms known as lower urinary tract symptoms (LUTS). BPH (benign prostatic hyperplasia) is the pathological entity that causes the symptoms known as LUTS. Now, it is important to understand that BPH is a benign process and by no means does it infer prostate cancer. In fact, many prostate cancers occur in small glands with very small amounts of BPH. Hyperplasia is a word that means overgrowth of cells. It is important to understand that BPH is not a precursor to the development of prostate cancer.

Table 1 • Symptoms of Lower Urinary Tract Symptoms (LUTS) Associated With BPH

•Decreased urine stream •Having to strain to empty bladder •Frequent urination (frequency) •Getting up at night to urinate (nocturia) •Urine stream stopping and starting (intermittency) •Difficulty starting urine stream (hesitancy) •Feeling bladder is not empty at end of urination (incomplete emptying)

The classic lower urinary tract symptoms include (Table 1): 1) incomplete emptying of the bladder—patients will often complain that they go to the bathroom, and five to ten minutes later, they need to return because they feel their bladders are not completely emptied; 2) frequency of urination— patients often complain about having to go to the bathroom very frequently, some men every thirty minutes during the day; 3) intermittency—this refers to a urine stream that is interrupted as you are urinating, in a staccato style; 4) urgency of urination, which implies that the patient has to get to the bathroom very quickly once he gets the first sensation that his bladder is full; 5) weak stream—men will notice that the force of their streams have decreased from when they were young men and they will have to strain to empty their bladders fully; 6) nocturia—this means having to get up in the middle of the night to pass urine. Some men have to do this more than every hour during sleep. You can imagine how sleep deprived these men can be. Appended to this chapter is the questionnaire which your physician is most likely to give you if you have symptoms consistent with LUTS.This questionnaire is known as the International Prostate Symptoms Score (IPSS). Below the questionnaire are scores which indicate level of symptoms. You can score yourself at the end of this chapter and see exactly where you stand. This is a useful test to do periodically to see what the progress of your BPH might be.

Prostate growth is related to hormone production. I previously talked about testosterone and its important role in male sexual development.Within the prostate, the testosterone is degraded to a hormone called dihydrotestosterone (DHT). It is DHT which causes most of the prostate growth. In fact, in men who have no testosterone and cannot produce DHT, the prostate is generally underdeveloped and fails to increase in size. Testosterone is degraded to DHT by an enzyme called 5–alpha reductase, and this enzyme is important because it is one of the targets of medical therapy for BPH and LUTS. There are likely to be other contributors to benign prostate growth, but the bottom line is that how the prostate grows is not well understood. Furthermore, why some men have very aggressive growth of the prostate and others do not remains a mystery.

One of the most serious problems associated with BPH is called urinary retention. This means that a man can no longer pass urine, that his prostate has become so swollen that it has essentially blocked off his urine channel completely. This can be extremely painful. The normal male bladder holds approximately 400 ml or about 13 oz of urine. We see men in the emergency room with urinary retention who, when they have catheters placed, have more than a litre of urine (33 oz) in their bladders and this, as you can imagine, is excruciatingly painful. When a man is in urinary retention, he needs to have his urine drained, and this is most frequently accomplished with the placement of a catheter through the penis, via the prostate, into the bladder. The most common catheter used is known as the Foley catheter, but there are a variety of catheters that urologists have at their disposal to bypass the blockage. Sometimes a man can have such enlargement of the prostate that placing a catheter through the penis is impossible and he needs one placed through the abdominal wall, known as a suprapubic catheter. Most men who have histories of urinary retention are going to require some significant intervention, usually surgery, for their prostates. One of the more common causes of older men passing into urinary retention is the use of over-the-counter cold medicines, which cause over-contraction of the prostate and bladder neck. So be cautious using these medications if your prostate is enlarged.

Another problem that BPH causes is changes in the bladder muscle. We know that when the bladder is contracting against increased pressure at the level of the prostate, over the course of time, it will undergo hypertrophy (bulking up) and scarring (collagen deposition). This scarring is probably a major factor in the development of symptoms such as nocturia, frequency of urination and urgency. Most importantly, when the BPH is treated, whether medically or surgically, if a man has had long-standing prostate enlargement, then it is likely that these symptoms mentioned above, known as irritative symptoms, will remain even if the prostate no longer exists as a result of the irreversible structural changes in the bladder.

Yet another problem that men with very large prostates may experience is the development of bladder stones. The chronic obstruction causes failure to empty the bladder, minerals will deposit in the urine that is left behind in the bladder, and these will eventually form stones. These may require a surgical procedure to be removed or fragmented. Finally, in extreme cases, pressure build-up can get so great that kidney damage can occur. It is common for urologists to see men who have urinary retention who also have reduced kidney function, although this is generally reversible. However, if left unattended for a long enough period of time, the kidney function can be irreversibly damaged.

If you have symptoms consistent with LUTS, then a conversation with your physician is important. Much of what is done regarding BPH and LUTS is related to the patient’s “bother index.” How bothered is he? If a man has a very large prostate gland, has normal urinary function, does not have much nocturia and has normal kidney function, then no treatment may be the best course of action. However, for men with even mild enlargement of the prostate gland who have tremendous symptoms (for example, getting out of bed five times every night and going to the bathroom once every hour during the day) even with normal kidney function, even without bladder stones, or a history of urinary retention, a medical or surgical option may be appropriate. Surgical therapy is generally reserved for patients who have failed medical therapy.