Inflammatory myopathies: Part 1

Abstract

The inflammatory myopathies have diverse clinical and pathological features and multiple etiologies. Some are confined to a single muscle or group of muscles (e.g., orbital myositis and localized nodular myositis) while others are diffuse. Infective forms may be due to viral, bacterial, fungal, protozoal, or parasitic organisms. Viruses may cause acute self-limited forms of myositis and have been isolated from muscle in some cases of acute rhabdomyolysis and inclusion body myositis. They have also been implicated in some cases of congenital myopathy and in polymyositis and dermatomyositis, but there is no evidence of viral invasion of muscle in these conditions. In polymyositis and dermatomyositis there are derangements in humoral and cellular immune function, and recent evidence suggests an underlying disturbance of immunoregulation. The roles of genetic factors, drugs, and Toxoplasma infection have been under scrutiny. There is increasing recognition of immunological and pathological differences in polymyositis and juvenile and adult dermatomyositis, and in cases with associated connective tissue diseases, suggesting different underlying pathogenetic mechanisms. Inclusion body myositis, eosinophilic myositis, and granulomatous myositis can be separated from the other idiopathic inflammatory myopathies because of distinctive clinical and pathological features and this may also reflect different mechanisms of muscle injury. Recent developments in the treatment of the idiopathic inflammatory myopathies include the use of plasmapheresis and total-body irradiation in cases that are resistant to corticosteroids and immunosuppressive drugs.

Cutaneous manifestations of dermatomyositis in male patient: a rare report

“…In our study, onset age was 32 years. It is reported that females outnumber males by 2:1 [13,14]. We reported this in male patient.…”

“…The cutaneous lesions usually precede the onset of weakness by 3 to 6 months, [6] however, Pearson [11] has described one case, with skin involvement for 13 years. It is known that DM has a bimodal age distribution: one peak occurs in children between 5-14 yr of age and a second, larger peak occurs between 45-64 yr of age [13,14]. In our study, onset age was 32 years.…”

Fatores de risco associados à calcinose na dermatomiosite juvenil

“…Characterization of this group of pathologies is based on its pattern of muscle involvement, the presence of associated clinical manifestations, histopathological findings, response to treatment and prognosis. [4][5][6] This is a rare disease that predominantly affects females, at a proportion of 2:1, and which has an incidence of 3.2/ 1,000,000 children and adolescents/year in the United…”

Diagnosis of dermatomyositis and polymyositis: a study of 102 cases

“…Proximal muscle weakness and inflammatory infiltrates within the skeletal muscle characterize polymyositis (PM). When myositis is accompanied by characteristic skin lesions, it is called dermatomyositis (DM) [1][2][3][4] . The skin manifestations include a heliotrope rash (blue-purple discoloration) on the upper eyelids with edema, a flat red rash on the face and upper trunk, and erythema of the knuckles accompanied by a raised, violaceous scaly eruption (Gottron's sign).…”

“…The incidence of PM, DM and inclusion-body myositis is approximately 1 in 100,000 3,5 . The cause of those diseases is still ignored, but the existence of genetic factors and autoimmune mechanisms is known 1,2,4,6 . Viral and bacterial infections as well as some drugs can also be related with the etiology of the inflammatory myopathies, but this type of condition needs to be distinguished from the idiopathic form being discussed 4,[6][7][8][9][10] .…”