Inflammatory myopathies

Inflammatory myopathies cover infectious, focal and immunogenic myopathies. This review focuses on the clinical features, diagnostic techniques, pathogenesis and therapy of immunogenic myopathies. Besides myositis associated with other autoimmune disorders, dermatomyositis is the most common immunogenic myopathy. The independent diagnosis of polymyositis has come under debate, since within this group of patients some are now diagnosed as having either hereditary muscular dystrophy with inflammatory signs or inclusion body myositis (IBM). Even more strikingly, patients diagnosed with sporadic IBM may now be diagnosed with either a form of hereditary IBM or with a form belonging to the group of protein aggregate myopathies or myofibrillar myopathies. This re-classification reflects the well-known and clinically evident therapeutic dilemma in many of these patients. Thus the indication for muscle biopsy or rebiopsy requires new consideration and attention.