Miopatías inflamatorias idiopáticas

Abstract

Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of immune-mediated disorders, characterised by inflammation of the skeletal muscle. The 8 groups defined histologically and clinically are as follows: polymyositis (PM), adult dermatomyositis (DM), juvenile DM, amyopathic DM, inclusion-body myositis (IBM), immune-mediated necrotising myopathy (IMNM), myopathies associated with neoplasia and myopathies associated with other systemic autoimmune rheumatic conditions in the context of overlap syndromes. In addition to muscle weakness, there may be other extramuscular manifestations such as cutaneous, joint, lung, digestive and cardiac conditions. Up to 60% of the patients with IIM have antibodies that can be divided into 2 large groups: myositis-specific antibodies and myositis-associated antibodies that can be present overlapping with other systemic diseases. Muscle biopsy is essential for their diagnosis, given that the histopathological study defines the type of myositis. Treatment consists of high doses of glucocorticoids that, most of the time, requires immunosuppressive therapy as well.