Sonographic evaluation of peripheral nerve involvement in leprosy with electrophysiologic correlation: a cross-sectional study in sub-Himalayan region

Abstract

Abstract Background Leprosy is an age-old chronic infectious disease with the majority of annual new case detections from South-East Asia. The disease manifestations coupled with the stigma attached to it often creates grave socioeconomic problems. Leprosy is curable and if detected and treated in the early stages can prevent disability. Ultrasonography provides information regarding location and degree of the nerve damage, nerve morphologic alterations, echo texture, fascicular pattern and vascularity. The aim of this study was to study the ultrasonographic features of neuropathy in leprosy with electrophysiologic correlation. Results A total of 34 histopathological proven cases of leprosy were included in this study, which was conducted for 1 year. High-resolution ultrasound (HRUS) of a total of 204 peripheral nerves in these 34 patients, including bilateral ulnar, median and common peroneal nerves, was performed. Cross-sectional areas, nerve diameters, nerve morphology and vascularity were noted and correlated with electrophysiologic study of these nerves. The results showed that all the patients having reduced motor or sensory function [decreased compound muscle action potential (CMAP), decreased compound nerve action potential (SNAP) and increased latency] in ulnar and common peroneal nerves were thickened on HRUS (100% in ulnar and common peroneal nerves) while 92% right median and 89% left median nerves with reduced motor or sensory function showed thickening on HRUS. Also, 5.8% ulnar nerves and 11.7% common peroneal nerves showed thickening on HRUS; however, sensory or motor conduction of these nerves was unaffected on nerve conduction study (NCS). So, a positive correlation was observed for nerve involvement as detected by ultrasonographic findings of nerve hypertrophy and the electrophysiologic study. The most common finding was focal or diffuse nerve thickening. Ulnar nerve was the most commonly thickened nerve in leprosy patients with the most common location of nerve thickening at medial epicondyle. Conclusions Ultrasound and electrophysiologic study of peripheral nerves in leprosy are complimentary to each other in diagnosing leprotic neuropathy.