Interstitial cystitis (IC) is a condition that consists of recurring pelvic pain, pressure, or discomfort in the bladder and pelvic region, often associated with urinary frequency (needing to go often) and urgency (feeling a strong need to go). It can also be referred to as:

IC can affect anyone. Women, men, and children of any age or race can develop IC, but it is most commonly found in women.  Three to 8 million women in the United States may have IC. That is about 3 to 6% of all women in the US. Approximately 1.5 million men have IC as well, however, this number is likely lower than the true rate because IC in men may often be mistaken for another disorder, such as chronic prostatitis/chronic pelvic pain syndrome.

Types of IC
Most IC experts agree that IC is actually several diseases rather than only one disease, and can present as different subtypes. Currently there are 2 recognized subtypes of IC: non-ulcerative and ulcerative.

• Non-ulcerative: 90% of IC patients have the non-ulcerative form of IC. Non-ulcerative IC presents with pinpoint hemorrhages, also known as glomerulations, in the bladder wall.  However, these are not specific for IC and any inflammation of the bladder can give that appearance. There is also no relationship between the number of glomerulations you have and how bad your symptoms are.
• Ulcerative: 5-10% of IC patients have the ulcerative form of IC. These patients usually have Hunner's ulcers or patches, which are red, bleeding areas on the bladder wall. Patients with Hunner's ulcers may benefit from treatment with laser surgery.

Researchers continue to study IC and investigate its different subtypes.

Causes of IC
The exact cause of IC remains a mystery, but researchers have identified a number of different factors that may contribute to the development of the disease. Many researchers believe a trigger (caused by one more events) may initially damage the bladder or bladder lining, and ultimately lead to the development of IC. Some of these triggers are: 

• Bladder trauma (such as from pelvic surgery)
• Bladder overdistention (anecdotal cases suggest onset after long periods without access to bathroom facilities)
• Pelvic floor muscle dysfunction
• Autoimmune disorder
• Bacterial infection (cystitis)
• Primary neurogenic inflammation (hypersensitivity or inflammation of pelvic nerves)
• Spinal cord trauma

It is thought that this damage to the bladder wall then allows particles in the urine, such as potassium, to leak into the bladder lining. Once these particles get into the bladder lining, they can lead to a variety of body responses that may further damage the bladder and cause chronic nerve pain. 

Researchers speculate that one reason for this continued damage to the bladder is that normal repair of the lining of the bladder does not occur in patients who develop IC. Research indicates that this might be due to a protein called antiproliferative factor (APF). Studies have shown that APF is produced by the cells of patients with IC, but not by the cells of healthy people. APF prevents the growth of bladder cells and the bladder may be unable to repair itself when APF is present. 

In recent years the relationship between IC and abuse (sexual, physical, and childhood sexual) has become a hotly debated topic.  The results of IC and abuse studies have varied greatly, indicating no connection, a slight connection, and a fairly high rate of incidence among those with IC.  Many studies have also indicated that the rate of abuse for people with IC is the same as the rate in the general population.  Finding a definitive answer to the abuse question may lie in using longitudinal studies which would follow a large group IC patients and controls over several years.  However, several researchers and clinicians believe that since there has been only modest data supporting the abuse theory, clinicians and researchers may be losing sight of their main goal -- providing real help to those with IC -- by focusing on this issue.

Revised October 29, 2009