Interstitial cystitis (in-tur-STISH-ul sis-TIE-tis) is a chronic condition causing bladder pressure, bladder pain and sometimes pelvic pain. The pain ranges from mild discomfort to severe pain. The condition is a part of a spectrum of diseases known as painful bladder syndrome.Your bladder is a hollow, muscular organ that stores urine. The bladder expands until it's full and then signals your brain that it's time to urinate, communicating through the pelvic nerves. This creates the urge to urinate for most people.With interstitial cystitis, these signals get mixed up you feel the need to urinate more often and with smaller volumes of urine than most people.Interstitial cystitis most often affects women and can have a long-lasting impact on quality of life.