Nerve fibre proliferation in interstitial cystitis.

The aetiology of pain in interstitial cystitis is not understood, although it has been reported to be due to release of mediators from mast cell granules. Cystolysis and intravesical instillation of dimethyl sulphoxide have been shown to relieve pain in this condition. We have studied the nerve population within the bladder wall using immunohistochemical stains for protein gene product 9.5. A group of 18 cases of chronic interstitial cystitis and 12 controls; neuropathic bladder (n = 1), chronic bacterial cystitis (n = 3), systemic lupus erythematosus cystitis (n = 2) and normals (n = 6), were investigated. There were significantly more nerve fibres within the sub-urothelial and detrusor muscle layers in chronic interstitial cystitis than there were in normals. Patients with chronic cystitis of other aetiology did not have a significant increase in nerve fibre density within the bladder wall suggesting a specific association between nerve fibre proliferation and interstitial cystitis. Cystolysis is shown to deplete selectively the submucosal nerve plexuses without altering the nerve density within detrusor muscle. This finding explains the desensitisation of the bladder without impairment of detrusor function after this procedure.