Detecção de assimetria de temperatura nas mãos de pacientes com hanseníase e contatos assintomáticos por termografia infravermelha indicando disfunção autonômica periférica

Abstract

Introduction: Leprosy is a chronic infectious disease caused by Mycobacterium leprae and is one of the most common causes of nontraumatic peripheral neuropathy worldwide. M. leprae affects nerve fibers that primarily affect thermal sensitivity followed by tactile sensitivity. One tools that has been used to evaluate body surface temperature alterations is infrared (IR) thermography. Thermographic images have been used to study diseases that cause surface temperature modification due to clinical abnormalities, such as peripheral autonomic neuropathy. Objective: the aim of present study was to use IR thermography to identify asymmetric temperature between both hands in leprosy patients and asymptomatic leprosy contacts. Material and Methods: It is a cross-sectional study with 48 leprosy patients (16 bordeline tuberculoid (BT), 10 mid-bordeline (BB), 10 bordeline lepromatous (BL) and 12 lepromatous (LL)), 66 asymptomatic contacts soropositive for anti-glycolipid-phenolic-1 (anti-PGL-I), 55 asymptomatic contacts seronegative (anti-PGL-I) and 23 healthy subjects. Skin temperature was measured by the FLIR® T420 IR camera in ten regions of interest (ROIs) in each hand at controlled room temperature. The Semmes-Weinstein monofilament sensory test was used to assess the loss of skin sensitivity and the voluntary muscle strength test to assess muscle strength loss was performed in all groups. Results: The presence of 3 or more points with hand asymmetry was not observed in healthy subjects. However, it was observed in 43.7% (26/48) of leprosy patients, with 37.5% (06/16) of BT, 40.0% (04/10) of BB, 40% (04/04). 10) LB and 58.4% (07/12) of LL, in 65.1% of seropositive contacts and 50.9% of seronegative contacts. The odds ratios of all groups presenting temperature asymmetry when compared with healthy subjects were: 5.7-fold chance for BT, 10.5-fold chance for BB, 6.7-fold chance for BL, and 13.5-fold chance for LL. However, seropositive contacts showed 26.1-fold chance to develop asymmetric temperature and seronegative contacts presented 9.6-fold than healthy. Regarding the patients who presented more chance to develop autonomic dysfunction than sensory and motor neural impairment, it was demonstrated that BT patients presented 25-fold more chance (p <0.05). However, other clinical forms were not statistically significant. Seropositive and seronegative contacts showed a high proportion of peripheral autonomic impairment detected by IR thermography when compared with sensory loss detected by monofilaments (p <0.05). Conclusion: The study highlights that IR thermography may detected temperature asymmetric in the hands of leprosy patients and asymptomatic seropositive and seronegative contacts, indicating peripheral autonomic dysfunction related to early neural impairment in this disease.