Clinical and laboratory studies in patients with leprosy and enthesitis

New insights at the interface between leprosy and immune-mediated rheumatic diseases

Leprosy is an infectious and contagious disease of slow evolution, triggered by Mycobacterium leprae. Arthritis is its third most common manifestation, after cutaneous and peripheral nerve involvement. Since musculoskeletal symptoms may be the initial presentation of the disease, it is important for health professionals to recognize its rheumatic manifestations for early diagnosis and appropriate treatment, especially in endemic areas. In addition, cases of leprosy have increased globally, notably in patients undergoing treatment with TNF-α blockers and due to the increase in migration and travel of people from developing countries to developed countries. This review proposes to discuss the main scenarios of mimicry of different rheumatic diseases by leprosy, as well as the role of immunosuppressive drugs used in rheumatology practice in the treatment of reactional states and in the risk of developing the infection.

Case of arthritis secondary to leprosy

Introduction

Leprosy is a chronic granulomatous infectious disease, which is caused by Mycobacterium leprae. High numbers of people are still affected by this disease in some of the developing countries however, it is rarely seen in non-endemic regions.

Cutaneous and neurological manifestations are the common and classical presentations of leprosy. Musculoskeletal involvement is the third most common manifestation but is less frequently reported.

Joint involvement can present as acute symmetrical polyarthritis or chronic polyarthritis resembling rheumatoid arthritis. Leprosy can also present with tenosynovitis, either isolated or associated with arthritis.

Case presentation

We report a case of 29-year-old man who developed tenosynovitis and acute symmetrical polyarthritis including small joints of hands and feet three weeks after appearance of typical cutaneous lesion of leprosy. Patient improved with steroid and anti leprosy treatment. Patient had another acute episode with symmetrical polyarthritis four months later while on treatment.

Discussion and Evaluation

In the modern era, there is increase movement of population from developing countries to developed countries, it is likely that patient suffering from leprosy with arthritis may present to rheumatology clinic in those countries where leprosy is not endemic. Exact pathogenesis for musculoskeletal manifestations is still not fully known. Our patient presented with symmetrical polyarthritis, enthesitis and systemic involvement, which was secondary to lepra reaction.

Having good knowledge of musculoskeletal manifestation of leprosy, will help narrow differential diagnosis and will prevent unnecessary diagnostic workup.

Conclusion

Leprosy can present with different rheumatologic manifestation including tenosynovitis and acute symmetrical polyarthritis. Type 2 lepra reaction (Erythema nodosum leprosum ENL) can present with systemic manifestation and can involve skin, nerves, joints, kidneys and liver.

Subcutaneous nodules and joint deformity in leprosy: case report and review

Leprosy (Hansen's disease), known to be caused by Mycobacterium leprae, is a well-known illness with multiple rheumatologic manifestations. This chronic granulomatous infection has clinical features that are variable, depending on the immune response of the host. Manifestations consist mainly of involvement of the peripheral nerves, skin, upper respiratory system, eyes, and testes, as well as joints. Musculoskeletal manifestations include arthralgias, arthritis, Charcot arthropathy, and positive autoantibodies. We report a case of a Puerto Rican-born woman who was living within the northeastern United States and had subcutaneous nodules, saddle nose deformity, and painless contractures of her fingers and toes. This case illustrates some of the musculoskeletal manifestations of leprosy to raise awareness of this disease as part of the differential diagnosis of articular abnormalities with subcutaneous nodules in a nonendemic country.

Possible mechanisms of chronic leprosy-related arthritis

Microbial agents induce arthritis through mechanisms such as direct infiltration of tissue and by inducing autoimmune phenomena. The mechanisms involved in this last type of arthritis have been investigated. In experimental models of adjuvant and reactive arthritis, the involvement of T cells in some cases mycobacteria in the development of arthritis have been confirmed. Cross-reactivity between the 65 kD mycobacterial protein and cartilage proteoglycans has been postulated as a possible mechanism. In this study, chronic peripheral arthritis was observed in patients with Hansen's disease, in patients with resolved Hansen's and in those with paucibacillary forms. This arthritis was not related to reactional states (erythema nodosum leprosum and reversal reaction), in contrast to several reports in the literature. The mechanisms by which microbes could induce chronic arthritis are discussed herein.

Humoral immunity in Hansen's disease

For many years immune response in leprosy has been studied. Since 1960 several reports dealing with humoral immunity have been described in the literature. Different autoantibody rates occur in leprosy. There is an increase in the prevalence of autoantibodies in elderly patients with long standing disease, in lepromatous leprosy and in those with reactional states. The differences in rates among various studies are attributed to different methods and variations among patient samples concerning age, gender, polar forms, therapy and other elements. The prevalence of numerous antibodies, immune complexes, cryoglobulins and complement levels have been studied by many authors. This also highlights the importance of the more recent reviews of anti-Mycobacterium leprae glycolipid antibodies such as the anti-phenolic glycolipid-I antibodies in which titers are variable and depend on genetic factors.

Bacterial infections: the arthritis of leprosy

Arthritis is a common feature of leprosy and contributes to disability. Direct invasion of joints and bones by mycobacteria may lead to a destructive arthritis in lepromatous disease. The infective process may involve few or many joints. Reactional states may occur spontaneously but usually after the initiation of anti-mycobacterial treatment. In both the type 1 reaction of borderline case and the type 2 reaction of the lepromatous disease, intense inflammation may occur at sites of infection. The immunology of the reactions is different but they share clinical features including a polyarthritis which may resemble rheumatoid disease. The joint disease may be chronic or relapsing, affecting the wrists and small joints of the hands in particular. Radiological erosions may occur. Mycobacterium leprae is not found in the synovium in this pattern of arthritis. Further study of this phenomenon might yield useful information above the mechanism of joint inflammation in other rheumatic diseases.