Unexplained delayed nerve impairment in leprosy after treatment

The objective of this study was to examine the clinical signs, symptoms and course of neuropathies in patients with leprosy who after treatment developed nerve impairment, not explained by relapse or reversal reactions. We searched the case-records of leprosy patients, seen between 1985 and 2002 at the department of dermatology at our centre. Included in the study were patients who had developed nerve impairment after treatment of leprosy in the absence of relapse, erythema nodosum leprosum, or reversal reactions, and who were referred to a neurologist. In these patients, we recorded age, onset of leprosy, type of leprosy, treatment of leprosy, signs and symptoms of delayed nerve impairment, results of electrophysiological studies, responses to treatment and course. Included were 14 patients, of whom eight had a (sub)acute multiple mononeuropathy (group I); and six had a slowly progressive multiple mononeuropathy (group II). Patients in group I had limited improvement of nerve impairment after treatment with corticosteroids, and recurrence of symptoms and signs (usually of the motor nerves) when corticosteroids were tapered off. Patients in group II had slowly progressive predominantly sensory nerve impairment. Initially, they had only subjective symptoms, after at least 3 years objective signs became detectable. These patients were not treated with immunosuppressants. Two groups of patients with unexplained delayed nerve impairment could be distinguished. One group had a multiple mononeuropathy resembling reversal reactions with insufficient response to corticosteroids. In these patients, more aggressive and prolonged immunosuppressive treatment should be considered. The aetiology for the neuropathy in the other group remains unclear and further investigations are needed to understand the pathogenesis before treatment recommendations can be given.