Chapter 12 Leprosy neuropathy

Abstract

The main electrophysiological finding of leprosy neuropathy is an asymmetrical involvement of the sensory or sensory and motor peripheral nerves, resulting in a sensory and/or sensory and motor mononeuritis or mononeuritis multiplex. Sensory loss is the cardinal symptom of leprosy neuropathy. Initially, there is isolated sensory loss in variable number and topography, because of the involvement of the dermal nerves. In lepromatous leprosy (LL) and borderline lepromatous leprosy (BL), this pattern of scattered sensory involvement constitutes a mosaic pattern of sensory loss that is highly suggestive of this disease, because of the associated temperature dependent distribution. Two very characteristic findings are decreased sensation at posterior aspect of the elbow, with no involvement of the distal arm, and hypoesthesia of the ear lobes, with preservation of face sensation. Later on, the nerve trunk is compromised and motor manifestations become present. Leprosy neuropathy is clearly a mononeuritis multiplex with a temperature dependent distribution that results in a preferential involvement of the ulnar nerve at elbow, peroneal nerve at the fibula neck, median nerve above the carpal tunnel, and posterior tibial nerve at the ankle.This distribution may superficially resemble a polyneuropathy in advanced cases, but even then the hottest areas of the patients are almost always preserved.