What is the definition or description of: interstitial cystitis?

Bladder wall inflamm: "cystitis" describes inflammation of the bladder, usually caused by a bacterial infection of the urine and the inner lining of the bladder. Much less commonly there are inflammatory conditions affecting the wall of the bladder under its lining, including the muscle tissue. Some of these cases are due to infections but many are not.

Interstitial cystiti: Interstitial cystitis is a chronic disease of the bladder, causing pain, for which the cause is presently unknown. It is associated with urinary frequency, urgency and waking at night to urinate. It is a diagnosis of exclusion, in that other causes of bladder pain/urgency/frequency should be excluded first. Ic can be diagnosed by bladder biopsy.