Clinical Reasoning: A case of bilateral foot drop in a 74-year-old man

Abstract

A 74-year-old man with no relevant medical history presented with 5 years of slowly progressive bilateral foot drop. He had used ankle foot orthoses for 3 years prior to presentation. There was no report of upper extremity weakness, numbness, paresthesia, myalgias, muscle cramps, or stiffness. He had attained age-appropriate developmental milestones as a child and was athletic, keeping up with his peers. His mother had bilateral foot drop, ankle contractures, and difficulty with ambulation. His brother, 2 daughters, and a son lacked similar symptoms. Neurologic examination showed bilateral distal lower extremity weakness (Medical Research Council grade 0/5 ankle dorsiflexion and eversion and grade 4/5 ankle plantar flexion and inversion), symmetric distal leg and intrinsic foot muscle wasting, absent patellar and Achilles tendon reflexes, and a steppage gait. Tone was reduced at bilateral ankles. Sensory examination including light touch, pinprick, vibration, and proprioception was intact. Mild bilateral pes cavus and hammertoes were noted. The remainder of the neurologic and physical examination was normal.

Evaluating Acute Bilateral Foot Drop: A Case Report

“…Bilateral foot drop with acute onset can result from many etiologies, including injury to the deep fibular or sciatic nerves, a compressive neuroma, muscular dystrophy that affects both tibialis anterior muscles, central nervous system pathologies (multiple sclerosis, stroke, amyotrophic lateral sclerosis), and even rapid intentional weight loss [ 4 ]. It is also important to note that some cases of acute bilateral foot drop may have a hereditary component, such as Charcot-Marie-Tooth disease [ 5 ]. However, most conditions of foot drop are related to chronic or progressive conditions rather than an acute onset of presentation.…”