Sonographic characteristics of median nerve neuropathy in Hansen’s disease: a case-control study

Background and objectives High-resolution ultrasonography (HRUS) has become a vital imaging tool in the management of leprosy. This case-control study analyzed the sonographic data on median nerves in leprosy and healthy controls to identify the features characteristic of leprosy. Methods Newly diagnosed and treatment naive Hansen's patients of both sexes and aged >16 years were included in the study. The control group included prospectively enrolled healthy subjects. Nerve conduction studies were performed in all. HRUS of the median nerve was performed using a Philips HD15 machine. HRUS parameters studied included cross-sectional area (CSA) of the nerve, fascicular architecture and abnormal blood flow (by colour Doppler). CSA was measured at the wrist (S1), 5 cm above the wrist (S2), 10 cm above the wrist (S3), mid-forearm (S4) and at the elbow (S5). Results 30 median nerves from 22 cases of leprosy and 30 nerves from 15 healthy subjects were compared. Among cases, 8 were borderline tuberculoid, 9 borderline lepromatous, 3 lepromatous leprosy, and 2 indeterminate leprosy. Abnormal motor (76.7%) and sensory conduction (96.7%) was noted in the patient group. The mean CSA was 18.5 [mm.sup.2] at S1, 20.3 [mm.sup.2] at S2, 14.1 [mm.sup.2] at S3, 9.1 [mm.sup.2] at S4, and 8.1 [mm.sup.2] at S5. The CSA at S1 and S2 were significantly higher compared to other sites. CSA values were significantly higher in patients compared to controls. The fascicular architecture was distorted in patients--grade II (33.3%), III (40.0%) and IV (20%), and hypervascularity was noted in 26.6%. Conclusion HRUS depicted characteristic features of the median nerve in leprosy maximum enlargement in the distal forearm with distorted fascicular architecture. Keywords: Hansen's disease, median nerve, nerve enlargement, distorted fascicular architecture, hypervascularity