Dermatomyositis with parenchymal lung involvement

Adverse impact of interstitial pulmonary fibrosis on prognosis in polymyositis and dermatomyositis

Interstitial pulmonary fibrosis occurs in approximately 9% of patients with PM/DM, yet its effect on the course of PM/DM has been scarcely noted. In this report, two patients with PM/DM and IPF were presented to highlight the fact that pulmonary disease can overshadow the primary muscle disorder and progress despite therapy with corticosteroids and nonsteroidal immunosuppression. Our patients were added to previously reported cases and an overview of PM/DM and IPF was presented. Sixty-seven patients with the diagnosis of PM/DM and IPF, with a mean age of 60 +/- 18 years, were identified. Pulmonary complaints were present in 64 cases. Fever was present in 18, arthritis or arthralgias in 11, and Raynaud's phenomenon in 9. Forty percent died after followup of 31 +/- 32 months. This mortality was significantly higher (P less than .05) than that in 745 historical controls with PM/DM without IPF. Progressive IPF was the immediate cause of death in 58% of those who died. A subgroup of 29 patients who had histologic documentation of both myositis and IPF had a mortality of 62% after 22 +/- 25 months. In this latter group, six patients had RP; five of these died. Patients who were not treated with corticosteroids also appeared to fare worse but, given the small number of patients involved, definite conclusions cannot be drawn. We conclude that patients with PM/DM can be adversely affected by the presence of IPF and that this negative impact may be exaggerated by RP and perhaps by lack of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Interstitial lung disease as the presentation of anti-Jo-1 positive polymyositis

A patient presenting with interstitial lung disease was predicted to have underlying polymyositis when found to be anti-Jo-1 antibody positive. When myopathy developed later with elevated serum creatine phosphokinase and myoglobin levels, the electromyogram was nonmyopathic, and polymyositis was confirmed by muscle biopsy. The case illustrates the value of anti-Jo-1 as a 'marker' autoantibody for polymyositis, and the need for thorough investigation of patients with interstitial lung disease of uncertain etiology. This should include indirect immunofluorescence using a dividing cell substrate and tests for antibodies to extractable tissue antigens. The need to completely evaluate patients with dermatopolymyositis is also emphasised.

Juvenile dermatomyositis

Myositis in childhood is characterized by elevated serum levels of muscle-derived enzymes, proximal symmetrical muscle weakness, abnormal EMG findings, and a muscle biopsy, which frequently documents an inflammatory process. In the pediatric age group, JDMS, which has characteristic cutaneous involvement in addition to myositis, is much more common than PM and is more common among female patients. With the use of steroids, mortality has been reduced from 33 per cent to 7 per cent. The development of calcifications can be the most debilitating consequence of JDMS. It is our premise that JDMS is a distinct disease entity and that the increase in HLA-B8 and DR3 in JDMS suggests that genetic background may predispose to disease development. There are conflicting data concerning immunologic abnormalities in JDMS, but there appears to be impairment of natural killing and evidence of complement activation. Results of tests for ANA frequently are positive in JDMS, but Jo-1 antibody, found in some adults with PM, has not been found in JDMS. Most newly diagnosed JDMS patients have antibodies to coxsackie B that may be related to the pathogenesis of this disease. Specific pathologic findings of endothelial cells containing reticulotubular inclusions are associated with small vessel occlusion, subsequent obliteration, and increased factor VIII levels in clinically active disease. In addition to physical therapy, steroids are used most frequently, but other immunosuppressive agents and plasmapheresis have been tried in severely ill children. Rigorous evaluation of the efficacy of these modalities is needed.