Brain Imaging in Fowler's Syndrome

Fowler's syndrome-chronic urinary retention and impaired bladder filling sensation without the presence of neurological disease-is a common cause of urinary retention in young women that responds well to treatment with sacral neuromodulation. The mechanisms of disease and therapy have remained difficult to understand, but two recent brain imaging studies-reviewed in this article-have helped dispel the obscurity. Despite different methodology, the two studies concur that brain responses to bladder filling are abnormal and are partially normalized after treatment, with restoration of voiding ability and sensation. The abnormal responses suggest exaggerated pro-continence behavior due to excessive afferent signals from an overactive urethra that inhibit bladder afferent signals at the sacral level. Sacral neuromodulation partially and artificially restores the bladder afferents but does not reverse the underlying sphincter overactivity.