[Necrotizing autoimmune myopathies].

[inclusion body myositis]

Necrotizing autoimmune myopathies are included in the spectrum of inflammatory myopathies , together with polymyosis , dermatopolymyosis and inclusion body myositis , despite the characteristic feature of marked muscular necrosis without inflammatory infiltrates . The clinical presentation is highly variable , often similar to the other inflammatory myopathies . The most common finding is nevertheless the severe form with rhabdomyolysis . The creatine kinase level is elevated (around 10 ,000 IU /l ) and electromyography shows myopathic changes with increased spontaneous activities reflecting the importance of the muscular necrosis . Muscle biopsy is required for diagnosis , revealing active necrosis of the muscle fibers without inflammatory invasion by CDA + or CD 8 + T -cells . Deposition of a microvascular membrane attack complex (C 5 b 9 ) is often noted , whereas the upregulation of MHC class 1 is rarely detected . Signs of endomysial microangiopathy are frequently reported . Necrotizing autoimmune myopathies can be associated with antisignal recognition particle (SRP ) antibodies or more rarely with the usual inflammatory myopathy antibodies . Paraneoplasic forms are described but remain exceptional . Lastly , necrotizing autoimmune myopathies , sometimes associated with statin therapy , have been recently described . They are linked with an antibody directed against 3 -hydroxy-3 -methyglutaryl-coenzyme A . Treatment is based on corticosteroid therapy , immunosuppressive drugs or intravenous immunoglobulins . Response is variable , depending on the clinical form .

Diseases
Validation

Diseases presenting "muscle fibers" symptom

epidermolysis bullosa simplex

focal myositis

inclusion body myositis

pyomyositis

systemic capillary leak syndrome

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