Review Question - QID 215083

A 65-year-old woman presents to her primary care physician complaining of fatigue and weakness. She lives independently, but over the past several months, she has had more difficulty performing many of her daily activities such as lifting objects, combing her hair, and getting up from a chair. She also endorses increased irritability, poor sleep, and a 15-pound weight gain despite no perceivable changes to her diet or activity. The patient takes hydrochlorothiazide for hypertension and metformin for type 2 diabetes. However, recently she has noticed elevated blood sugars at home despite adhering to her standard medication regimen. At the clinic, her temperature is 98.6°F (37.0°C), blood pressure is 155/110 mmHg, pulse is 68/min, and respirations are 12/min. Physical exam shows a woman with centripetal obesity, skin atrophy, and scattered bruises. Musculoskeletal exam reveals bilateral 4/5 shoulder and hip abduction, 5/5 wrist flexion and extension, and 5/5 ankle dorsiflexion and plantar flexion. Reflexes are normal. Which of the following is the most likely diagnosis in this patient?