A 76-year-old woman complained of progressive proximal
muscle weakness; achy pain in the buttocks, thighs, and
calves; and lilac discoloration of her eyelids, cheek, nose,
knuckles, and fingernails.
Examination confirmed heliotrope skin changes and
disclosed moderate weakness in the limb and girdle musculature.
The patient's levels of muscle enzymes, including
creatine kinase, aldolase, aspartate aminotransferase,
alanine aminotransferase, and lactate dehydrogenase,
were elevated, as was her erythrocyte sedimentation rate.
An electromyogram revealed increased exertional activity,
fibrillation potentials, and a typical myopathic pattern.
Muscle biopsy was performed, and the findings were consistent
with inflammatory myositis. Evaluation for an underlying
malignancy yielded negative results.
The diagnosis of idiopathic dermatomyositis was
based on 4 criteria: clinical picture, electromyographic
findings, elevated serum creatine kinase level, and biopsy
report. The patient was treated with prednisone, 60 mg/d,
and was given physical therapy. Three months later, her
strength had improved by 80%.
(Case and photograph courtesy of Dr Gavin I. Awerbuch.)