Interstitial cystitis (IC) is a chronic, non-infectious condition in which the tissue between the lining and the muscular wall of the bladder becomes damaged. Although the most common type of cystitis is caused by a bacterial infection and can be successfully treated with antibiotics, medical tests reveal no bacteria in the urine of patients with IC, nor do these individuals respond to antibiotic therapy. Of the more than 700,000 Americans estimated to have IC, 90 percent are women, mainly middle-aged.

Many symptoms of IC resemble those of a urinary tract infection: pain and pressure in the bladder and pelvis, a burning sensation on urination and the need to urinate frequently - at least eight times a day. Pain and discomfort increase as the bladder fills and are relieved as it empties. Eventually, inflammation causes permanent scarring of the bladder wall, which prevents the bladder from stretching to accommodate a normal amount of urine.

IC is difficult to diagnose and can be mistaken for kidney disorders, sexually transmitted diseases, vaginal and uterine infections. Diagnostic tests include urine culture, cystoscopy to view the inside of the bladder and biopsy of the bladder wall.

Researchers are working to understand the causes of IC. One theory is that IC is an autoimmune response following a bladder infection. Another is that a bacterium may be present in bladder cells but undetectable through routine urine tests. Heredity may also play a part in IC.

Since the causes are unknown, treatments are aimed at relieving symptoms. Most people are helped by one or a combination of treatments. Pentosan polysulfate sodium (Elmiron), the first oral drug developed for IC, was approved by the FDA in 1996. In clinical trials, Elmiron improved symptoms in 38 percent of patients treated. Drugs called anticholinergics can decrease bladder spasms and increase bladder capacity to some degree. Other medications such as amitriptyline, which is normally used for depression, may help relieve symptoms, as well as pain associated with a full bladder.

Some patients find that certain foods stimulate the bladder, and they can prevent flare-ups by avoiding them. Among the culprits: alcohol, caffeine, chocolate, carbonated beverages, fruits and fruit juices, tomatoes, and artificial sweeteners. Another source of relief involves retraining the nerves and muscles to increase the time between urinations by small increments each week. Surgery is considered only if all available treatments have failed and the pain is disabling.

The support of family, friends, and others with IC is vital to helping patients cope. Studies have found that patients who learn about the disorder and become involved in their care do better than patients who do not.