A 42-year-old woman comes to the physician because of a worsening muscle stiffness, myalgia, and a 7-kg (15-lb) weight gain. Her last menstrual period was 4 months ago. Physical examination shows cold, dry skin, and proximal muscle weakness. Deep tendon reflexes are 2+ bilaterally, with delayed relaxation. Blood pressure is 140/90 mm Hg and pulse is 56/min. BMI is 26 kg/m². The serum creatine kinase concentration is 2,940 U/L. Which of the following tests is most likely to identify the cause of this patient's muscle weakness?

Question

Quizplus · Accepted Answer

Eductional Objective: Hypothyroid myopathy presents with myalgias, proximal muscle weakness, elevated creatine kinase levels, and delayed relaxation of deep tendon reflexes.  The diagnosis can be confirmed with an elevated TSH level.  Other common causes of myopathy with elevated creatine kinase levels include inflammatory myopathies, muscular dystrophies, and HMG-CoA reductase inhibitors.

A 42-Year-Old Woman Comes to the Physician Because of a Worsening