Question of the Week
For September 9, 2014
A 40-year-old man with no significant medical history presents to the emergency department with a headache and with left-arm numbness and tingling that, over the course of 2 days, have spread to his left face and left leg. Shortly before presentation, he also noted clumsiness with his left hand and difficulty walking, with a tendency to fall to the left. He denies any history of recreational drug use.
On examination, the patient is afebrile with a heart rate of 87 beats per minute and a blood pressure of 120/87 mm Hg. He has no head or spine tenderness, no neck stiffness, and no skin lesions. Cardiac examination reveals no murmurs.
Neurologic examination reveals a left-pronator drift, left lower facial weakness, and mild left weakness of ankle dorsiflexion. He has loss of sensation to light touch, vibration, and temperature on his entire left face, arm, and leg.
Which one of the following diagnoses is most likely in this case?