Primary Neural Leprosy mimicking rheumatological disorders

SUMMARY Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which affects mainly the skin and peripherical nerves. Brasil has not yet achieved its goal of elimination of the number of cases of this disease, ranking second in terms of absolute numbers worldwide, with India occupying the first position. Primary Neural Leprosy is considered to be a challenge in diagnosis, since it affects the peripherical nerve system with the absence of skin lesions, thus mimicking rheumatological disorders, like in the case presented. A male, 31, with no previous comorbidities, five years ago, started feeling severe pain in the left ankle as well as morning hand pain and stiffness. After many years of being submitted to intense rheumatological disease investigation, they all proved to be negative. Upon physical examination, the patient presented no skin lesions, symmetric polyarthritis in metacarpophalangeal joints and thickness of the left sural nerve. Lab exams showed no alterations and bacilloscopy was negative. Ultrasonography was used to investigate the thickness of the left sural nerve. Biopsy showed a minimal amount of perineural lymphocytes and positive AFB testing. Based on the electroneuromyography, the conclusion was multiple mononeuropathy, and multibacillary polychemotherapy was started. Leprosy remains a public health problem in Brasil. Due to the high prevalence of the disease, our medical colleagues must be alert and trained to recognize this clinical presentation of leprosy. Correct referral to Reference Centers accelerates research, contributing to an accurate diagnosis, classification, and treatment, thus preventing irreversible sequelae with severe functional disability.