Cystitis
Cystitis is infection of the bladder.
Cystitis is common in women, particularly during the reproductive years. Some women have recurring episodes of cystitis. There are a number of reasons for this--the short length of the urethra and the closeness of the urethra to the vagina and anus, where bacteria are commonly found. Sexual intercourse can contribute, too, because the motion can cause slight injuries to the urethra and a tendency for bacteria to ascend to the bladder. Pregnant women are especially likely to develop cystitis because the pregnancy itself can interfere with emptying of the bladder.
Use of a diaphragm increases the risk of developing cystitis, possibly because spermicide used with the diaphragm suppresses the normal vaginal bacteria and allows bacteria that cause cystitis to flourish in the vagina. Rarely, cystitis recurs because of an abnormal connection between the bladder and the vagina (vesicovaginal fistula).
Cystitis is less common in men. In men, cystitis generally starts with an infection in the urethra that moves into the prostate, then into the bladder. The most common cause of recurring cystitis in men is a persistent bacterial infection of the prostate. Although antibiotics quickly clear bacteria from the urine in the bladder, most of these drugs cannot penetrate well enough into the prostate to cure an infection there. Consequently, when drug therapy is discontinued, bacteria that remain in the prostate tend to reinfect the bladder. Cystitis can also be caused by a catheter or an instrument used during surgery that introduces bacteria into the bladder.
If the flow of urine becomes partly obstructed because of a kidney stone or an enlarged prostate, infected urine cannot pass and the number of bacteria increases so that bacteria have a greater opportunity to cause an infection above the point of obstruction.
In men and women, an abnormal connection between the bladder and the intestine (vesicoenteric fistula) can develop, allowing air to enter the bladder and sometimes enabling bacteria that produce gas to enter and grow in the bladder. Air bubbles can appear in the urine (pneumaturia). A structural abnormality (such as a drooping uterus and bladder) may cause poor emptying of the bladder and predispose a person to cystitis.
Sometimes the bladder can become inflamed without an infection being present (interstitial cystitis).
 See the sidebar Interstitial Cystitis: Bladder Inflammation, Not Infection.
Symptoms
Cystitis usually produces a frequent, urgent need to urinate and a burning or painful sensation while urinating. The urgent need to urinate may cause an uncontrollable loss of urine (incontinence), especially in older people. Fever is rarely present. Pain is usually felt above the pubic bone and often in the lower back as well. Frequent urination during the night (nocturia) is another symptom. The urine is often cloudy and contains visible blood in about 30% of people. Symptoms may disappear without treatment.
Sometimes cystitis produces no symptoms, particularly in older people, and is discovered when urine tests are performed for other reasons. A person whose bladder is malfunctioning because of nerve damage (neurogenic bladder (see Section 11, Chapter 147)) or a person who has a permanently placed catheter may have cystitis with no symptoms until a kidney infection or an unexplained fever develops.
Diagnosis
A doctor can diagnose cystitis based on its typical symptoms. A midstream (clean-catch) urine specimen (see Section 11, Chapter 142) is collected so that the urine is not contaminated with bacteria from the vagina or the tip of the penis. A strip of test paper is sometimes dipped into the urine to perform two quick and simple tests for substances that are normally not found in the urine. The testing strip can detect nitrites that are released by bacteria. The testing strip can also detect the presence of leukocyte esterase (an enzyme found in certain white blood cells), which may indicate that the body is trying to clear the urine of bacteria.
The urine specimen is examined under a microscope to see whether it contains red or white blood cells or other substances. Bacteria are counted, and the sample is cultured to identify the type of bacteria. If the person has an infection, one type of bacteria is usually present in large numbers.
In men, a midstream urine specimen is usually sufficient for the diagnosis. In women, a specimen is more likely to be contaminated with bacteria from the vagina or vulva. When the urine contains only small numbers of bacteria, or several different types of bacteria simultaneously, the urine has likely been contaminated during the collection process. To ensure that the urine is not contaminated, a doctor sometimes must obtain a specimen directly from the bladder with a catheter.
It is important for the doctor to find the cause of urinary tract infections in several different groups. The cause should be found in children younger than 5, in men at any age, and in women with frequently recurring infections (3 or more per year), especially when accompanied by symptoms of obstruction, an upper urinary tract infection, or infection with the Proteus bacteria. In these types of people, there is a greater likelihood of finding a cause that requires specific treatment other than giving drugs to treat the infection (for example, a large kidney stone). Doctors may perform an x-ray study in which a radiopaque dye, visible on x-rays, is injected into a vein, then excreted into the urine by the kidneys. The x-ray films then provide images of the kidneys, ureters, and bladder. Performing voiding cystourethrography, which involves injecting a radiopaque dye into the bladder and filming its exit, is a good way to investigate the backflow (reflux) of urine from the bladder, up the ureters, particularly in children, and may also identify any narrowing (stricture) of the urethra. Retrograde urethrography, in which the radiopaque dye is injected directly into the urethra, is useful for detecting stricture, outpouching, or an abnormal connection (fistula) of the urethra in both men and women. Looking directly into the bladder with a flexible viewing tube (cystoscopy) may help diagnose the problem when cystitis does not improve with treatment.
Treatment
People who have frequent bladder infections may continuously take low doses of antibiotics. The antibiotic can be taken daily, 3 times a week, or immediately after sexual intercourse.
Drinking plenty of fluids may help to prevent cystitis. The flushing action of the urine washes many bacteria out of the bladder; the body's natural defenses eliminate the remainder.
Cystitis is usually treated with antibiotics. Treating cystitis that has no symptoms may be harmful, because bacteria that are resistant to many antibiotics may flourish. However, cystitis is treated during pregnancy even when the woman has no symptoms, because of a higher risk that organisms might reach and infect the kidneys. Before prescribing antibiotics, the doctor determines whether the person has a condition that would make cystitis more severe, such as a structural abnormality, diabetes, or a weakened immune system (which reduces the person's ability to fight infection). Such conditions may require more potent antibiotics taken for a longer period of time, particularly because the infection is likely to return as soon as the person stops taking antibiotics.
For women, taking an antibiotic by mouth for 3 days is usually effective if the infection has not led to any complications, although some doctors prefer to use a single dose. For more stubborn infections, an antibiotic is usually taken for 7 to 10 days. For men, an antibiotic is usually taken for 10 to 14 days because a shorter duration of treatment is associated with frequent recurrences.
A variety of drugs are used to relieve symptoms, especially the frequent, insistent urge to urinate and painful urination. Certain drugs, such as atropine, may relieve bladder spasms that cause the sense of urgency. Other drugs, such as phenazopyridine, reduce the pain by soothing the inflamed tissues.
Surgery may be necessary to relieve any physical obstruction to the flow of urine or to correct a structural abnormality that makes infection more likely, such as a drooping uterus and bladder. Draining urine from an obstructed area through a catheter helps control the infection. Usually, an antibiotic is given before surgery to reduce the risk of the infection spreading throughout the body.
See the sidebar Preventing Bladder Infections in Women.
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