Electrophysiological profiles of leprosy neuropathy

Objective: To know the electrophysiological pattern of peripheral neuropathy in leprosy.
Methods: We recruited consecutive, newly diagnosed leprosy patients without leprosy reactions for the study. Sensory and motor nerve conduction studies were carried out in the neuro-electrophysiology laboratory. Motor studies were done bilaterally for the median, ulnar, radial, common peroneal and tibial nerves. Likewise, sensory studies were done for the median, ulnar, radial and sural nerves. All findings were recorded on a preset pro-forma.
Results: Seventy-four patients were enrolled. The mean age was 35·09 ^ 14·92 years, ranging between 12 and 73 years. The median duration of illness was 7·5 (3·75–15) months. The male to female ratio was 2:1. Almost half of the patients (43%) had impaired nerve conduction at the time of diagnosis. Sensory neuropathy was more frequent (32%) compared to motor (20%). Sensory-motor axonal type was the commonest (37·5%) pattern of peripheral neuropathy. Ulnar (24%) and sural (22%) nerves were the most commonly affected motor and sensory nerves respectively. Amplitude was the most commonly affected parameter of both the sensory nerve action potential (SNAP) and the compound motor action potential (CMAP) and it was impaired in 100% of nerves having impaired nerve conduction.
Conclusion: Sensory-motor axonal type was the commonest pattern of peripheral neuropathy in leprosy. From our study, amplitude can be considered as the most informative parameter, but further studies are recommended.