Newly diagnosed and treatment naïve 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).

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 mm² at S1, 20.3 mm² at S2, 14.1 mm² at S3, 9.1 mm² at S4, and 8.1 mm² 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%.

HRUS depicted characteristic features of the median nerve in leprosy - maximum enlargement in the distal forearm with distorted fascicular architecture.

52 patients with involvement of 70 median nerves (18 bilateral) were enrolled. They had palpable median nerves, along with sensory and motor loss. 16 patients were lost to follow up by 2 years, so that 36 patients with 50 median nerves (14 bilateral) remained for review. These cases were randomly divided into two groups: one group was given steroids while the second group was given steroids along with surgical nerve decompression. The results were evaluated for improvement or deterioration of the sensory and motor symptoms, along with pain.

The results support the proposition that surgical decompression of the nerve together with steroid treatment, is a better option to prevent the progression of deformities due to median nerve involvement, than steroids alone. 

Clinically, borderline tuberculoid (BT) classification was the commonest subtype with 34% cases, followed by borderline lepromatous (BL) and lepromatous (LL). The incidence of multibacillary (MB) cases was high (83%) and grade 2 disability was seen in 23% cases. Concordance between clinical diagnosis and skin histopathology was 75.8%, while between clinical diagnosis and nerve histopathology was 68%. Skin and nerve histopathology were in concordance in 60% of cases. Electrophysiological assessment revealed derangement in 88.5% of cases with sensory nerve conduction parameters being the commonest and earliest to be affected. Analysis revealed a significant association between deranged parameters and thickness of the superficial peroneal nerve, sural and common peroneal nerves. Subclinical involvement was high in most nerves studied. Cases at the tuberculoid end of the spectrum showed more of segmental demyelination, whereas lepromatous cases showed a mixture of axonal and demyelinating changes.

A high degree of concordance was seen between dermal and nerve histopathologies, especially towards the poles of the leprosy spectrum. With an increasing trend towards MB cases and grade 2 disability, our study validates nerve conduction study to be a very sensitive screening tool to detect Hansen’s disease in its early stages and also to identify the type of nerve degeneration. Nerve histopathology may be considered as the gold standard for confirmation of the diagnosis of leprosy.