Inflammatory myopathies: clinical, diagnostic and therapeutic aspects.
The three major forms of immune-mediated inflammatory myopathy are dermatomyositis (DM), polymyositis (PM), and inclusion-body myositis (IBM). They each have distinctive clinical and histopathologic features that allow the clinician to reach a specific diagnosis in most cases. Magnetic resonance imaging is sometimes helpful, particularly if the diagnosis of IBM is suspected but has not been formally evaluated. Myositis-specific antibodies are not helpful diagnostically but may be of prognostic value; most antibodies have low sensitivity. Muscle biopsy is mandatory to confirm the diagnosis of an inflammatory myopathy and to allow unusual varieties such as eosinophilic, granulomatous, and parasitic myositis, and macrophagic myofasciitis, to be recognized. The treatment of the inflammatory myopathies remains largely empirical and relies upon the use of corticosteroids, immunosuppressive agents, and intravenous immunoglobulin, all of which have nonselective effects on the immune system. Further controlled clinical trials are required to evaluate the relative efficacy of the available therapeutic modalities particularly in combinations, and of newer immunosuppressive agents (mycophenolate mofetil and tacrolimus) and cytokine-based therapies for the treatment of resistant cases of DM, PM, and IBM. Improved understanding of the molecular mechanisms of muscle injury in the inflammatory myopathies should lead to the development of more specific forms of immunotherapy for these conditions.
Mastaglia
Frank L
FL
Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Australia. flmast@cyllene.uwa.edu.au
Garlepp
Michael J
MJ
Phillips
Beverley A
BA
Zilko
Paul J
PJ
D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001323:Autoantibodies / Q000235:genetics* / Q000276:immunology; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D018482:Muscle, Skeletal / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology; D009220:Myositis / Q000276:immunology / Q000473:pathology* / Q000628:therapy*
D000893:Anti-Inflammatory Agents; D001323:Autoantibodies; D016756:Immunoglobulins, Intravenous; D007166:Immunosuppressive Agents