A 54-year-old man comes to the office due to recurrent falls. During ambulation, the patient prominently flexes his right hip and knee and the right foot slaps to the floor with each step. Romberg sign is absent. Which of the following is the most likely cause of this gait abnormality?

Question

A 54-year-old man comes to the office due to recurrent falls.  During ambulation, the patient prominently flexes his right hip and knee and the right foot slaps to the floor with each step.  Romberg sign is absent.  Which of the following is the most likely cause of this gait abnormality?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d5c2_4b99_bc81_3158ba9efe54_MD0003_00 This patient has a high-stepping or "steppage" gait due to right foot drop. Foot drop is due to weakness in foot dorsiflexion. To compensate for this, patients must flex the hip and knee to raise the foot and avoid dragging the toe with each step. Steppage gait is most commonly caused by L5 radiculopathy or neuropathy of the common peroneal nerve. L5 radiculopathy is typified by back pain radiating to the foot, often with weakness of foot eversion and dorsiflexion. Peroneal neuropathy is due to compression of the nerve at the lateral aspect of the fibula (eg, due to prolonged crossing of the legs or squatting) and is associated with paresthesias and sensory loss over the dorsum of the foot; foot inversion and plantar flexion (tibial nerve) are normal. The diagnosis can be clarified with electromyography and nerve conduction studies. (Choice A) Lesions in the basal ganglia can present with a slow shuffling gait as seen in patients with Parkinson's disease. (Choice B) Cerebellar ataxia can result from lesions of the vermis (truncal ataxia) or the cerebellar hemispheres (limb ataxia). Features of cerebellar ataxia include staggering and swaying from side to side, impaired tandem gait and titubation (truncal tremor). (Choice D) Pyramidal tract or corticospinal tract (CST) lesions can cause spastic ataxia. The gait appears stiff or rigid with circumduction (the spastic leg is abducted and advanced while in extension and internal rotation) and plantar flexion of the affected limb. (Choice E) Damage to the cortico-cortical white matter fibers of the frontal lobe, as seen in normal pressure hydrocephalus, can lead to gait apraxia (Bruns ataxia). Strength, coordination, and sensory functions are intact, but there is difficulty in initiation of forward movement of the feet when they are in contact with the ground ("magnetic gait"). (Choice F) Patients with loss of proprioception due to sensory neuronopathy may have postural or gait instability and a wide-based gait. Patients may stomp their feet against the floor (slap gait) to help them know where their lower limbs are relative to the ground. Educational objective: Unilateral foot drop is characterized by a "steppage" gait: exaggerated hip and knee flexion while walking. Common causes include L5 radiculopathy and compression peroneal neuropathy. References: Common peroneal nerve palsy caused by compression stockings after surgery. (http://www.ncbi.nlm.nih.gov/pubmed/24743458) Gait: the role of the ankle and foot in walking. (http://www.ncbi.nlm.nih.gov/pubmed/24559869) Common peroneal nerve palsy due to hematoma at the fibular neck. (http://www.ncbi.nlm.nih.gov/pubmed/23283631)

A 54-Year-Old Man Comes to the Office Due to Recurrent