Therapy of myositis

Idiopathic inflammatory myopathy consists of dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM) and necrotizing autoimmune myopathy (NAM). At all stages of myositis, physiotherapy is effective in improving muscle strength, endurance and in maintaining joint motion. In DM and PM the therapy is initiated with glucocorticosteroids. Steroid-sparing agents (azathioprine, methotrexate and cyclosporin A) are added to prevent Cushing's syndrome or an unsatisfactory response. Therapy can also be escalated with intravenous immunoglobulins. Tacrolimus and mycophenolate mofetil (MMF) were effective in small case series. Cyclophosphamide is restricted to patients not responding to previous agents. For treatment intensification immunoglobulins can also be combined with MMF. There is not enough evidence to routinely recommend rituximab. The results with TNF-alpha inhibitors and plasmapheresis were negative or inconsistent. In DM skin involvement responds to sun blockers, antimalarials, topical corticosteroids or calcineurin inhibitors. In NAM statins should be discontinued and treatment with prednisone and immunosuppressants initiated. In IBM a therapeutic trial with prednisone, methotrexate or azathioprine may be warranted, especially in cases in which the serum creatine kinase (CK) is elevated or an inflammatory infiltrate is present in the muscle biopsy.