Interstitial cystitis (IC) is a condition that results in recurring discomfort or pain in the bladder and the surrounding pelvic region. The symptoms vary from case to case and even in the same individual. People may experience mild discomfort, pressure, tenderness, or intense pain in the bladder and pelvic area. Symptoms may include an urgent need to urinate (urgency), a frequent need to urinate (frequency), or a combination of these symptoms. Pain may change in intensity as the bladder fills with urine or as it empties. Women's symptoms often get worse during menstruation. They may sometimes experience pain with vaginal intercourse.
Because IC varies so much in symptoms and severity, most researchers believe that it is not one, but several diseases. In recent years, scientists have started to use the term painful bladder syndrome (PBS) to describe cases with painful urinary symptoms that may not meet the strictest definition of IC. The term IC / PBS includes all cases of urinary pain that can't be attributed to other causes, such as infection or urinary stones. The term interstitial cystitis, or IC, is used alone when describing cases that meet all of the IC criteria established by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
In IC / PBS, the bladder wall may be irritated and become scarred or stiff. Glomerulations (pinpoint bleeding caused by recurrent irritation) often appear on the bladder wall. Hunner's ulcers are present in 10 percent of patients with IC. Some people with IC / PBS find that their bladders cannot hold much urine, which increases the frequency of urination. Frequency, however, is not always specifically related to bladder size; many people with severe frequency have normal bladder capacity. People with severe cases of IC / PBS may urinate as many as 60 times a day, including frequent nighttime urination (nocturia).
IC / PBS is far more common in women than in men. Of the estimated 1 million Americans with IC, up to 90 percent are women.
What causes IC?
Some of the symptoms of IC / PBS resemble those of bacterial infection, but medical tests reveal no organisms in the urine of patients with IC / PBS. Furthermore, patients with IC / PBS do not respond to antibiotic therapy. Researchers are working to understand the causes of IC / PBS and to find effective treatments.
In recent years, researchers have isolated a substance found almost exclusively in the urine of people with interstitial cystitis. They have named the substance antiproliferative factor, or APF, because it appears to block the normal growth of the cells that line the inside wall of the bladder. Researchers anticipate that learning more about APF will lead to a greater understanding of the causes of IC and to possible treatments.
Researchers are beginning to explore the possibility that heredity may play a part in some forms of IC. In a few cases, IC has affected a mother and a daughter or two sisters, but it does not commonly run in families.