Management of Polymyositis and Dermatomyositis

Calcinosis in Rheumatic Diseases

BACKGROUND

Calcinosis, or dystrophic soft-tissue calcification, occurs in damaged or devitalized tissues in the presence of normal calcium/phosphorus metabolism. It is often noted in the subcutaneous tissues of connective tissues diseases--primarily systemic lupus erythematosus, scleroderma, or dermatomyositis--and may involve a relatively localized area or be widespread. The calcinotic accumulations may lead secondarily to muscle atrophy, joint contractures, and skin ulceration complicated by recurrent episodes of local inflammation and infection.

OBJECTIVES

To review the classification, pathogenesis, clinical features, and treatment of calcinosis in rheumatic diseases.

METHOD

A MEDLINE search of articles from 1972 to 2004 was conducted utilizing the index word "calcinosis" with the coindexing terms "scleroderma," "lupus," "dermatomyositis," and "dystrophic calcification."

RESULTS

Calcinosis may be the source of both pain and disability in connective tissue disease patients. Illustrative cases of patients with severe calcinosis are described. The literature available was critically reviewed. While warfarin, colchicine, probenecid, bisphosphonates, diltiazem, minocycline, aluminum hydroxide, salicylate, surgical extirpation, and carbon dioxide laser therapies have been used, no treatment has convincingly prevented or reduced calcinosis.

CONCLUSIONS

Calcinosis is common in the conditions reviewed and a number of agents have been used for treatment. However, the approach to calcinosis management is disorganized, beginning with the lack of a generally accepted classification and continuing with a lack of systematic study and clinical therapeutic trials.

Cyclosporin in the management of polymyositis and dermatomyositis

Three patients with polymyositis refractory to conventional steroid and immunosuppressive treatment, but responsive to cyclosporin A, are described. In a fourth patient cyclosporin A was used as a first line drug in combination with steroids in the treatment of life-threatening dermatomyositis. Cyclosporin A in the management of polymyositis/dermatomyositis requires formal assessment of its costs and benefits compared with conventional treatments.

Juvenile dermatomyositis induced by toxoplasmosis

A 10-year-old girl from southern Alberta, Canada, who had close contact with cats, developed typical features of dermatomyositis. The diagnosis was confirmed by muscle biopsy. A toxoplasmosis titer was 1:16,384 by indirect fluorescent antibody technique, and the IgM response to toxoplasma was positive. Only minimal improvement followed prednisone and azathioprine administration, but she rapidly improved after 4 weeks of treatment for toxoplasmosis with pyrimethamine and sulfadiazine. A year after the onset of dermatomyositis, she showed no weakness or cutaneous lesions, and a repeat muscle biopsy no longer showed inflammation, perifascicular atrophy, or regeneration of myofibers. She remains asymptomatic more than 2 years after discontinuation of all medications. Investigation for immune deficiency disease 1 year after therapy revealed that lymphocytic response to T-cell and B-cell mitogens was normal, as were immunoglobulin and complement levels. She had mild impairment of natural killer cell activity and a positive antinuclear factor. Her rapid improvement on specific therapy and lack of significant long-term immune deficiency is consistent with acute toxoplasmosis infection in an immunologically competent child.

Dermatomyositis-polymyositis in children

Sixteen cases of dermatomyositis-polymyositis in children (dermatomyositis 15; polymyositis 1) have been reviewed. Proximal muscle weakness with a characteristic skin rash was vital for diagnosis in the majority of children. The positive laboratory tests such as creatine phosphokinase (CPK), electromyography (EMG) and muscle biopsy were helpful but results were normal in some cases even in the acute phase of the illness. All but one had been treated initially with high dose corticosteroids followed by a low dose maintenance for a prolonged period. Two in addition had had cytotoxic agents. Thirteen of the sixteen were currently in remission. In the other three cases, one with polymyositis only, the disease remained active and the two with dermatomyositis died. Only three of the patients were incapacitated by residual fixed contractures and extruding calcinosis. On the whole the prognosis of dermatomyositis is good.

High single-dose alternate-day corticosteroid regimens in treatment of polymyositis

High single-dose alternate-day prednisolone therapy (ADT) was compared with daily-dose prednisolone therapy (DDT) for treatment of polymyositis. Thirty patients with polymyositis were treated with ADT for an average of 33.9 months. The combined number of improvements was 21 out of 30, a response rate of 70%. Side-effects were very rare and mild. On the other hand, 9 of 17 patients treated with DDT for an average 18.5 months improved, a response rate of 53%. The incidence of side-effects was strikingly higher than with ADT. ADT is therefore strongly advocated for treatment of polymyositis to avoid infectious complications and lessen cushingoid side-effects.