A 59-year-old woman comes to the physician for a routine health maintenance examination. She has had a 1-year history of pain and stiffness of her shoulders and hips. She has hypertension managed with lisinopril. Vitals are normal. BMI is 25. Physical examination shows 4/5 strength bilaterally in both the upper and lower extremities. Serum creatine kinase is 400 U/L (NR 30-180). Her brother has rheumatoid arthritis. Which of the following is the most likely diagnosis?
Drug adverse effect
Fibromyalgia
Myotonic dystrophy
Polymyalgia rheumatica
Polymyositis
