Arthritis as presenting manifestation of pure neuritic leprosy--a rheumatologist's dilemma

OBJECTIVES: Leprosy classically presents with cutaneous and neurological manifestations. In diagnosed cases of leprosy, rheumatological involvement varies from 1% to 70%. A primary articular presentation without cutaneous manifestations is not yet known. Herein, we present our experience of five cases of leprosy that presented with predominant articular involvement in the absence of cutaneous manifestations. METHODS: The study was conducted in the Department of Clinical Immunology, Sanjay Gandhi Postgraduate Institute of Medical Sciences located in the state of Uttar Pradesh, one of the nine endemic states in India. Case records of patients with a definite diagnosis of leprosy were screened for the presenting manifestations, pattern of articular involvement, tenosynovitis, neurological signs and symptoms. Reports of nerve conduction study (NCS), nerve and synovial biopsy and other diagnostic tests were retrieved from laboratory records. Available radiographs were examined for evidence of juxta-articular osteopenia and erosions. RESULTS: Case records of 11,740 patients were screened, of which 28 had a diagnosis of leprosy. Twenty patients had presented with rheumatological complaints primarily. Five of the patients who presented with inflammatory arthritis with/without tenosynovitis (n = 4) and tenosynovitis alone (n = 1) had pure neuritic leprosy. All of these patients had thickened peripheral nerves and abnormal NCS. Sural nerve biopsy confirmed the diagnosis of leprosy in all these cases. CONCLUSION: A combination of tenosynovitis and thickened nerves in association with symmetric polyarthritis should raise a suspicion of leprosy even in the absence of cutaneous features.