The bladder is the hollow organ in the lower abdomen that stores urine. As the bladder fills, muscles in its walls relax so that it can expand. As the bladder empties during urination, the muscles contract to squeeze the urine out through the urethra.
Interstitial cystitis (IC) is a chronic condition in which the bladder becomes inflamed and irritated. The inflammation stiffens the bladder wall, and makes it difficult for the bladder to fully expand when filling with urine. IC may be caused by a defect in the bladder lining. Women are much more likely than men to have the condition.
A main symptom is pain, which is strongest when the bladder fills and eases when the bladder empties. Pain may also be felt more generally in the lower back, abdomen, or groin. People with this condition may also urinate more frequently or feel an urgent need to urinate, yet they may only pass a little bit of urine each time. Sexual problems may also be related to interstitial cystitis.