A 43-year-old woman comes to the physician because of a 3-week history of progressive weakness. She has had increased difficulty combing her hair and climbing stairs. She has hypertension. She has smoked one pack of cigarettes daily for 25 years. She does not drink alcohol. Her mother had coronary artery disease and systemic lupus erythematosus. Her current medications include chlorthalidone and vitamin supplements. Her temperature is 37.8°C (100.0°F), pulse is 71/min, and blood pressure is 132/84 mm Hg. Muscle biopsy reveals major histocompatibility complex class I molecule overexpression on the sarcolemma with CD8⁺ lymphocyte infiltration. Which of the following is the most likely cause of this patient's condition?

Question

Quizplus · Accepted Answer

Eductional Objective: Polymyositis causes symmetric proximal muscle weakness. Muscle biopsy reveals inflammation, necrosis, and regeneration of muscle fibers. Over-expression of major histocompatibility complex class I proteins on the sarcolemma leads to infiltration with CD8⁺ T lymphocytes and myocyte damage.

A 43-Year-Old Woman Comes to the Physician Because of a 3-Week