Cystitis is almost always caused by bacterial infection. Nearly all episodes of cystitis (90%) are caused by bowel bacteria known as E. coli.
The bowel is full of bacteria from the intestines. E. Coli are common there. Many bacteria are harmless and live normally on the skin of the perineum.
Urine in the bladder normally is considered sterile and contains few bacteria. Urinating usually washes away germs that may enter the bladder. The body's immune system and its natural germ-fighting substances in the bladder's lining also eliminate many organisms.
Infection results when bacteria enter the urinary tract system and multiply faster than either urinating or the body's natural defenses can remove them.
Women are especially prone to cystitis because the bowel opening is near the urethra. If the urethra becomes contaminated with bowel germs, the bacteria can travel up the urethra and into the bladder, causing inflammation.
Some everyday activities can cause bowel germs to enter the urethra. Those include:
For women, wiping incorrectly from back to front after a bowel movement. Always wipe from front to back.
Sexual intercourse or other activities that push germs into the bladder, such as rough foreplay.
Insertion of instruments into the urinary tract, such as a catheter or cystoscope.
A woman's urethral opening is much closer to the anus than a man's is. That makes it easier for germs to get from the bowel area to the urethral opening.
A woman's urethra also is much shorter than a man's, so bacteria travel a shorter distance to reach the bladder:
A woman's urethra is about 1 and 1/2 inches long.
A man's urethra is about 8 inches long.
What Increases the Risk for Cystitis?
Some things you do or conditions you have can increase your risk for cystitis. These include:
Infrequent urination in both men and women. "Holding it in" causes urine to stagnate, which helps bacteria flourish and grow.
Skin allergies. Some women are allergic to ingredients in vaginal creams, soaps, bath products, or other products used in the perineal area.
Lowered resistance. The body's natural defenses can be lowered from colds, flu, stress, or other causes.
Incomplete emptying of the bladder. Many conditions can block urine flow and prevent the bladder from emptying completely, such as kidney stones.
Changes in normal acidity of vaginal fluid, such as after a douche. Women should not douche unless directed to do so by a doctor.
Occasionally, no bacterial cause can be found for a bladder inflammation. These episodes may result from:
Irritation of the urethra
Sexually transmitted diseases
Why Do Older People Get Cystitis So Often?
Elderly people are at increased risk for cystitis primarily because they often cannot empty their bladders completely. This inability is associated with conditions such as:
Enlargedprostate gland, a common condition as men age. An enlarged prostate can slow the flow of urine, which fosters bacterial growth.
Inflammation of the prostate gland in men, a condition called prostatitis.
Narrowing of the urethral opening, a common occurrence in people who are older.
Inability to control the bowels.
Decreased mobility or total immobility.
Poor nutrition. Older people often eat and drink less than they should. Poor eating can increase risk of infection. Drinking too little can cause urine to become concentrated and to foster bacterial growth.
Nice To Know:
Q. My mother is in a nursing home. She just had a catheter put in, and I'm worried that she'll get a bladder infection on top of everything else she's gone through. Anything I can do?
A. You are right to be concerned. People who have urinary catheters for any length of time can develop large numbers of bacteria in their urine. People who can't move well are also at higher risk for infection. Catheters should be used only when necessary and removed as soon as possible.
Talk it over with the doctor. Does she really need one? Or is it simply a convenience for the nursing home staff?
If your mother must have a catheter, make sure it is replaced every two weeks to help reduce the risk of infection. Make sure the nursing staff irrigates the bladder with antibiotics between replacements. The drainage bag should never be on the floor.
Every day and after each bowel movement, both the catheter and the area around the urethra should be cleaned with soap and water. Check to see that the bag is kept securely in place against her leg.
Encourage your mother to drink lots of fluids and assist her if she needs help. If she can tolerate cranberry or blueberry juice, see that she gets three glasses a day.
Q. Since going through menopause my mother hasn't had a bladder infection, yet she used to get them a lot. She says her secret is hormones. How so?
A. Women who use a vaginal cream containing estrogen seem to avoid many bladder infections. Some experts believe that estrogen may resist infection by increasing the number of a certain kind of "good" bacteria, called lactobacilli. These bacteria fight infection by changing the character of the vaginal discharge and preventing E. coli-the most common cause of cystitis-from adhering to vaginal cells.
Oral estrogen may not have the same benefit. Some studies show that women who take oral estrogen actually have more urinary tract infections.
Why Doesn't Everyone Get Attacks?
The healthy human body normally harbors a wide variety of bacteria and other organisms. But the body's natural defenses usually keep them in check.
These natural defenses also kick in when the body is exposed to potentially disease-causing germs from outside.
If the body's natural defenses become overwhelmed, bacteria and other germs can multiply in force and cause infection.