Via practica 12/2008

DIAGNOSIS, TREATMENT AND LONG-TERM FOLLOW UP IN PATIENTS WITH POLYMYOSITIS AND DERMATOMYOSITIS

Polymyositis (PM) and dermatomyositis (DM) are two major catogeries of idiopathic inflammatory myopathies. These disorders are clinically, histologically, and pathogenically distinct. PM is T-cell-mediated disorder directed against muscle fibers. PM generally presents in patients over the age of 20 years and is more prevalent in females. Proximal limb muscles, trunk and neck muscles are primarilly affected in PM and also DM. Imunopathogenetically is DM a humorally mediated microangiopathy. Most childhood cases manifest between 5 and 15 years (juvenile DM) and most adult cases present between 45-65 years of age. 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 PM and DM. PM and DM are usually responsive to corticosteroids (prednisone is the treatment of choice) and to immunosuppressive agents (azathioprine, cyclophoshamide, etc). In cases of PM and DM refractory to corticosteroids and immunosuppressive agents have IVIg and rituximab, and in DM also plasmapheresis, beneficial responses. Most PM a DM patients require long-term immunosuppressive therapy and long-term follow up. This review covers the histopathology, pathogenesis, clinical presentation, diagnosis, treatment and prognosis of PM and DM.

Keywords: dermatomyositis, polymyositis, pathogenesis, clinical features, diagnosis, treatment, prognosis, long-term follow up