Intravesical capsaicin in patients with detrusor hyper-reflexia - A placebo-controlled cross-over study

The aim of this study was to determine whether intravesical treatment with capsaicin could block detrusor hyper-reflexia (DH) and alter the substance P content, nerve fibres and mucosa of the bladder. Twelve patients with spi nal cord disease with DH and urinary incontinence resistant to anticholiner gic treatment underwent intravesical administration of 50 ml 2% lignocaine, followed by either 100 ml 1 mmol/l capsaicin or 100 mi physiological salin e for 30 min. Cross-over to the alternative treatment took place after 4 we eks. Varying degrees of burning sensation were experienced by all but one p atient during the capsaicin treatment and precluded the possibility of cond ucting studies of this type in a blind manner. No preference for capsaicin treatment was found, and micturition and VAS scores were unchanged after tr eatment with capsaicin. The mean volume of the contents of the bladder at w hich DH first appeared was 175 mi after saline and 195 ml after capsaicin ( mean difference 20 ml with a 5% confidence interval from -25 to 65). Bladde r biopsies taken 2 weeks after treatment with capsaicin showed more pronoun ced inflammation, superficial haemorrhage, squamous epithelial metaplasia a nd a more condensed bladder stroma. Immunohistochemical staining for substa nce P and neuronal cell adhesive molecule revealed the presence of small te rminal axons and small nerve bundles in all of the biopsies. Intravesical t reatment with capsaicin did not have a beneficial effect on DH or a destruc tive effect on nerve fibres. It did, however, produce significant reactive changes in the mucosa of the bladder.