Erectile dysfunction in multiple sclerosis.

In a sample of 29 impotent men with multiple sclerosis and erectile problems, penile arterial inflow and venous outflow were within normal limits. In 26 patients, the pudendal evoked potential (PEP) was abnormal, and eight of these also had abnormal bulbocavernous reflex (BCR). Three patients had abnormal PEP and normal BCR, and of these, two had normal and one had abnormal nocturnal erectile activity. The validity of PEP/BCR testing was supported by normal findings in six patients with MS and without erectile problems. Nocturnal erectile activity was normal in 11 patients, of whom nine had abnormal PEP and/or BCR. A high disability score corresponded poorly with both reduced sexual function, insufficient nocturnal erectile activity, and abnormal PEP and/or BCR. Intracavernous injection of papaverine gave erection in 27 patients, the dose needed to create an erection being inversely related to the level of disablement. PEP and BCR testing may be more sensitive in defining neurogenic erectile dysfunction (ED) than nocturnal erectile activity. We considered 26 of the cases to have a neurogenic cause of ED and three to have mainly a psychogenic cause.