Interstitial cystitis (IC) is a chronic inflammatory condition of the
bladder that causes frequent, urgent, and painful urination and pelvic
discomfort. The natural lining of the bladder (epithelium) is protected from
toxins in the urine by a layer of protein called glycoaminoglycan (GAG). In
IC this protective layer has broken down, allowing toxins to irritate the
bladder wall. The bladder then becomes inflamed and tender and does not
store urine well.
Unlike common cystitis (inflammation of the bladder caused by bacterial
infection), which is associated with urinary tract infections (UTI)
and usually treated with antibiotics, no infectious agent has been found in
IC. Though not curable, IC is treatable and most patients find some relief
with treatment and lifestyle changes.
Incidence and Prevalence
According to the National Institutes of Health, IC affects about 700,000
people in the United States, 90% of which are women. The average age of
onset is 40 years. Although only 25% of cases involve people under age 30,
the number of children affected by IC may be greater than commonly believed.
IC is often misdiagnosed, and sufferers may see several doctors over the
course of years before a diagnosis is made. Increasing awareness of the
disease is helping to speed diagnosis and treatment.
Causes and Risk Factors
IC is a poorly understood disease with unknown causes. Although no
bacteria or viruses (pathogens) have been found in the urine of IC
sufferers, an unidentified infectious agent may be the cause. Others believe
that IC occurs with ischemia (tissue death) or a deficiency of GAG in the
epithelium. It may be an autoimmune disease, in which the immune system
attacks healthy cells, perhaps following a bladder infection. Spasms of the
pelvic floor muscles may also contribute to the IC symptoms. It is likely
that several factors cause the condition.
Other conditions associated with IC include the following:
- Food allergies
- Hay fever (pollen allergy)
- Irritable bowel syndrome
- Rheumatoid arthritis
The connection between IC and these conditions is not understood.
IC may occur following gynecological surgery. Some evidence suggests an
increased risk for IC in Jewish people, and studies of mothers, daughters,
and twins who suffer from it suggest a hereditary risk factor.