Myositis

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton  

Introduction

Myositis is a group of rare conditions where the body’s immune system turns against itself and destroys healthy muscle tissue instead of building new muscle tissue. Myositis is also known as idiopathic inflammatory myopathies (IIMs). This set of acquired diseases affect the muscle but may additionally affect other organs. Myositis mainly occur in middle-aged patients, most showing a subacute weakness and myalgia in the upper and lower limbs.

Sub-Types

Include these types:

• Dermatomyositis, which can affect the muscle and presents with a typical skin rash.
• Inclusion body myositis, with a purely muscular expression and leads to a slow progressive deficit
• Immune-mediated necrotizing myopathies, with a severe muscle involvement often presents from the onset of the disease
• Antisynthetase syndrome, which combines muscle damage, joint involvement and a potentially life-threatening lung disease
• Overlapping myositis, which combines muscle damage with other organs involvement connected to another autoimmune disease.

Diagnosis of Myositis

Diagnosis is based on diligent clinical examination, electromyographic studies and immunological testing for myositis specific antibodies. Muscle biopsy is no longer routinely recommended when the antibodies are typical, unless the form of IIM issometimes difficult to classify.

Treatment

To date scores immunosuppressive and immunomodulatory therapeutic agents are available for the treatment of myositis. Glucocorticosteroids and immunosuppressants remain first-line therapy in many cases with early start and sufficient dosing potentially leading to stabilization of the disease, improvement of strength and decrease in inflammation. Unfortunately the side effects of immunosuppressive treatment may be undesirable. New therapeutic approaches targeting specific immunological pathways are show great promise.

Sub Heading 3

Physical training leads to a stabilization of disease progression. In some studies with small groups of patients, an exercise program at home improved muscle strength and endurance. In particular, concentric sport activities cause less injury to muscle fibers than eccentric sport activities. The stretching during eccentric sport activities can cause myalgia, elevated inflammatory activities, and an increase of CK. An immobilization in patients with myositis is obsolete.104 Patients with IBM also show an improvement upon physical training: an aerobic training, which included cycling and resistance exercise over 12 weeks, three times per week, showed an improvement in muscle strength and was well tolerated. The CK levels did not change significantly after the training period.105 A randomized single-blinded phase II trial tested a 12-week aerobic training program in patients with Charcot-Marie-Tooth disease type 1A (CMT) and IBM. The primary outcome was the peak oxygen uptake during a maximal exercise test. The results show that aerobic training clearly improves the primary outcome, especially in IBM. Another important aspect is the safety and feasibility of aerobic programs.106 The evidence in the literature clearly supports moderate physical exercise in patients with myositis.

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