Dermatomyositis

DERMATOMYOSITIS, dermatomyositis, is a disease of unknown origin, more often acute than subacute or chronic, characterized by a series of muscular, cutaneous, and nervous phenomena. It affects both sexes equally, and children rarely. It is observed more often in winter. The disease is rare: about 60 cases have been described. In its etiology, infection (staphylococci or streptococci, etc.) apparently plays a role. There are indications of a connection with tuberculosis, especially chronic forms of the disease. The toxic theory (poisoning by fish, etc.) has few followers. Oppenheim links dermatomyositis with the influence of cold. The first observations of dermatomyositis date back to 1887, when Unverricht, Wagner, and Hepp published their cases independently of one another. The term dermatomyositis was introduced in 1891 by Unverricht due to the combination of cutaneous and muscular phenomena in the clinical picture of the disease. At autopsy, an enlarged soft spleen and changes in the muscles and skin are usually found. Histologically, it is an interstitial myositis with degeneration and disintegration of muscle fibers, and inflammatory phenomena in the skin that have nothing typical; in neuro-myositis forms, there is, in addition, edema of the nerve trunks in acute cases, and proliferation of connective tissue elements in chronic forms. The disease most often begins with a prodromal period lasting from 1 to 3 weeks and characterized by malaise, fatigue, drowsiness, rheumatoid pains, dyspepsia, etc.; more rarely, acute pains in the muscles, most often the lower legs, which hinder movement, set in immediately. Soon, edema of the muscles, their swelling, and rigidity appear; many muscles can suffer, and the temperature rises. Above the affected muscles, the skin is edematous, tense, firm, and does not leave pits upon pressure; puffiness of the face may be added. When the muscles of the chest wall are involved, dyspnea and asphyxia are observed. Subsequently, erythema, blisters, purpura, pigmentation, etc., may be observed on the skin of the affected areas. Itching is absent. Sometimes the mucous membrane of the mouth is involved in the painful process. Gradually, the edema of the muscles increases, hindering active and passive movements; contractures develop, and the muscles of the diaphragm and heart may also be affected; the face takes on the appearance of a 'mask.' Nervous symptoms are also possible: paresthesias, neuromyositis, pareses; later, atrophy of the muscles with a reaction of degeneration. Deep reflexes are weakened. The function of the bladder and rectum does not suffer. The spleen is often enlarged. Chronic dermatomyositis is expressed by dermatomyosclerosis, which sharply brings it closer to scleroderma. Whether dermatomyositis and scleroderma are similar processes is an open question. The diagnosis of dermatomyositis in some cases is difficult to distinguish from polymyositis, polyneuritis, and trichinosis. In polymyositis, there is a quantitative decrease in electrical excitability, reaching complete extinction; in dermatomyositis, this is absent. With a reaction of degeneration with typical inversion of poles and with disorders of the sensory nerves, one is more inclined to think of polyneuritis than of dermatomyositis. In the first days of the disease, trichinosis is more characterized by localization in the muscles of the head than of the extremities, and it is encountered more often in the form of group diseases than as isolated cases. The finding of trichinae is of decisive importance. Prognosis. Dermatomyositis is a severe disease, yielding a high percentage of deaths. According to Steiner (1905), 17 out of 28 patients died. In a benign course, recovery is possible. Sometimes dermatomyositis was limited to one particular group of muscles or one limb. Death usually occurs in the first 3-4 weeks from asphyxia, progressive weakness, aspiration pneumonia, or cardiac complications. Treatment is symptomatic.