High-Resolution Sonography: A New Technique to Detect Nerve Damage in Leprosy

Mycobacterium leprae, which causes leprosy, infects peripheral nerves resulting in functional impairment, ulcer formation and stigmatizing deformities. Early diagnosis of nerve involvement is important to avoid nerve related complications. We used non-invasive, high-resolution sonography (US) and color Doppler (CD) imaging to study the ulnar (UN), median (MN), lateral popliteal (LP) and posterior tibial (PT) nerves in 20 leprosy patients and compared 30 healthy Indian controls. The nerves were significantly thicker in the patients (p<0.0001 for each nerve). One of the key signs of leprosy is the presence of enlarged nerves. The kappa for clinical palpation and nerve enlargement by sonography was 0.30 for all examined nerves. Increased neural vascularity, the sign of inflammation was observed in 26% (39/152) of nerves by CD imaging. Increased CD was observed in multiple nerves in 3 of 4 patients with type 2 reaction. Significant correlation was observed between clinical parameters of grade of thickening, sensory loss and muscle weakness and US abnormalities of nerve echotexture, endoneural flow and cross-sectional area (p<0.001). We conclude that sonography is a better diagnostic tool to predict nerve damage as compared to clinical assessment. Nerve damage was sonographically more extensive and was observed in nerves considered clinically normal

Lower touch sensibility in the extremities of healthy Indians: further deterioration with age

Touch sensibility testing is a cost-effective, psychophysical measure of peripheral nerve function and impairment. However, there is limited information regarding the natural variability in touch sensibility across different populations and different age groups. We studied 568 healthy Indian volunteers without any clinical evidence of peripheral nerve disease. Touch sensibility was evaluated bilaterally in palms, feet, and heels, using Semmes-Weinstein monofilaments, with target forces ranging from 0.008 to 300 g. No differences were observed between the right and the left limbs. The lowest target force detected ranged from 0.4 to 2 g in the palms and 1.4 to 15 g in the feet. These values showed further increase with age. Women compared with men had higher sensibility in the palms in most age groups. Touch sensibility thresholds recorded in a large group of Indians were higher than that reported in other populations. These findings have clinical implications for the diagnosis of early nerve impairment in the elderly and in disease states drawing attention to geographic variations in touch sensation