Idiopathic reduced bladder storage versus interstitial cystitis.

Idiopathic reduced bladder storage is a term we used to describe a group of patients who have subjective and objective evidence (by cystometrogram) of diminished bladder capacity without a demonstrable cause. We performed a prospective study comparing this condition with interstitial cystitis. We studied the clinical, urodynamic and histological features, and response to therapy in these 2 groups of patients. No statistical difference was found between the incidence of irritative bladder symptoms and/or suprapubic pain. Only minor differences were noted in the maximum cystometric capacity and incidence of bladder instability. Histological and immunofluorescent features were analogous. Also, the reduced bladder storage and interstitial cystitis patients responded similarly to bladder dilation and pharmacological therapy. Augmentation ileocystoplasty used in patients refractory to medical treatment produced comparable results in the short term. Based upon similar findings, it is likely that these 2 conditions represent the same disease entity with the only difference being the cystoscopic findings.