Peter Špalek
Polymyositis (PM), dermatomyositis (DM) and inclusion body myositis (IBM) are three major catogeries of idiopathic inflammatory myopathies. These disorders are clinically, histologically, and pathogenically distinct. Imumunopathogenetically is DM a humorally mediated microangiopathy. DM is more prevalent in females. DM can present at any age. Most childhood cases manifest between 5 and 15 years (juvenile DM) and most adult cases present between 45 - 65 years of age. Onset of proximal and symmetrical muscle weakness is typically subacute (over weeks), although it can develop abruptly (over days) or insidiously (over months). Myalgias occur in approximately 50 % of patients. Characteristic rash usually accompanies or precedes the onset of muscle weakness. An increased incidence of underlying malignancy (10 - 40 %) occurs in adult DM. Bohan´s and Peter’s clinical, biochemical, EMG and histopathological criteria are practical and sensitive for diagnosis of DM. DM is usually responsive to corticosteroids (prednisone is the treatment of choice in DM) and to immunosuppressive agents (azathioprine, cyclophoshamide, etc). In cases of DM refractory to corticosteroids and immunosuppressive agents have IVIg and plasmapheresis beneficial responses.