QBANK A 55-year-old woman presents to her primary care physician complaining of increasing difficulty climbing stairs and getting out of chairs over the las

[DianaZ]

A 55-year-old woman presents to her primary care physician complaining of increasing difficulty climbing stairs and getting out of chairs over the last several months. She denies fatigue, muscle aches, weight loss, fever, or joint pain. She does not take any medications and denies the use of drugs or alcohol. Physical examination reveals a reddish-purple discoloration and swelling of the eyelid, as pictured. In addition, a scaly, erythematous rash is seen over the knuckles. Which of the following test results would most likely establish the probable diagnosis?

A. Absent anti-nuclear antibodies
B. Decreased erythrocyte sedimentation rate
C. Decreased membrane irritability on electromyography
D. Elevated serum creatine kinase