USMLE® Board Review Exam Apps & Resources

A 54-year-old woman presents to your office complaining of difficulty walking. She describes severe weakness and occasional pain in her thigh muscles. She has stumbled and fallen several times over the last week. Her past medical history is significant for hypertension treated with hydrochlorothiazide and metoprolol. She consumes two to three cans of beer on weekends. Her younger brother died of a neurological disease when he was 20 years old. Her mother suffers from hypertension and diabetes mellitus. Her heart rate is 90/min and blood pressure is 170/100 mmHg. Chest examination is within normal limits. A bruit is heard over the left carotid artery. Neurologic examination reveals hyporeflexia and decreased strength in all muscle groups. Her ESR is 12 mm/hr. ECG shows flat and broad T waves with occasional premature ventricular contractions. Which of the following is the most likely cause of this patient's current complaints?