A 76-year-old woman presented several days after a sudden onset of left foot drop that occurred immediately after a fall. She also complained of anorexia, weight loss, malaise, and numbness in both lower extremities for several weeks.
Past medical history was positive for coronary artery disease, carotid endarterectomy, aortic valve stenosis with valve replacement, hypertension, and hyperlipidemia. Medications included atenolol, hydrochlorothiazide, amlodipine, thyroid supplement, and aspirin.
She was referred for an EMG.
General physical examination was normal. On neurologic examination, strength was intact except for mild weakness in both hands and toe dorsiflexors on the right, and she could not dorsiflex the left foot and toes or evert the left foot. Reflexes were absent in the ankles, trace at the knees, and normal in the arms. She had absent vibration sense in the toes and ankles and decreased pinprick, temperature, and touch sensations in both lower extremities in a stocking distribution up to the calf. There was mildly decreased vibration sense and two-point discrimination in the fingers. The rest of the examination was normal.
What is the Differential Diagnosis?
Clinically, this patient had a polyneuropathy with a superimposed left peroneal neuropathy. It was not completely clear if peroneal palsy was caused by stretch trauma from the fall or was spontaneous and caused the fall. The differential diagnosis included a diabetic polyneuropathy. Other causes of neuropathy were also considered, including a polyneuropathy from a microangiopathic vasculitis. She could also have had a polyneuropathy with an L5 radiculopathy, plexopathy, or a sciatic nerve lesion.
