Dr. Meyers presented a complex case of a patient presenting with subacute progressive rash, fevers, and dyspnea found to have acute progressive hypoxemic respiratory failure with diffuse consolidations. After an extensive workup for infectious and rheumatologic disease, the patient was ultimately diagnosed with the amyopathic variant of dermatomyositis. Some takeaways per Dr. Meyers:
- Clinical amyopathic dermatomyositis (CADM) is defined by classic skin findings of dermatomyositis in the absence of weakness or muscle enzyme abnormalities in the setting of compatible serologic findings
- It tends to affect white and asian females slightly more often than the general population
- A subset of amyopathic dermatomyositis patients develop antibodies to MDA5 which is unfortunately associated with a more rapid decline and rapidly progressive interstitial lung disease (which can be clinically indistinguishable from ARDS)
- ILD associated with dermatomyositis and polymyositis can pose a clinical dilemma
- Pathology c/w NSIP, UIP, organizing PNA, and acute interstitial PNA
- Response of muscle and skin involvement correlate or predict response
- Systemic steroids initial therapy
- If CADM or antisynthetase syndrome, it is recommended to add second immunosuppression agent immediately at the time of diagnosis given the rapid and aggressive course assocaited with these syndromes
- The presence of ferritin levels >1500 correlates with a lower survival in these patients and may be helpful in determining whether earlier and more aggressive immunosuppression is warranted while awaiting the more definitive serologic tests which can take days to weeks to return. (1)
Thanks again to Dr. Meyers for this interesting case!
- Gono T, Kawaguchi Y, Hara M, Masuda I, Katsumata Y, Shinozaki M, Ota Y, Ozeki E, Yamanaka H. Increased ferritin predicts development and severity of acute interstitial lung disease as a complication of dermatomyositis. Rheumatology (Oxford). 2010;49(7):1354–60.