Foot drop

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Overview
Foot drop is a deficit in turning the ankle and toes upward (dorsiflexion). Conditions leading to foot drop may be neurologic, muscular or anatomic in origin, often with significant overlap.

Features
Foot drop is characterized by steppage gait. When the person with foot drop walks, the foot slaps down onto the floor. To compensate for the toe drop, the patient must raise the thigh excessively, as if walking upstairs. Individuals with foot drop are unable to walk on their heel, flex their ankle, or walk with the normal heel-toe pattern.

Patients with painful disorders of sensation (dysesthesia) of the soles of the feet may have a similar gait, but do not have foot drop. Because of the extreme pain evoked by even the slightest pressure on the feet, the patient walks as if walking barefoot on hot sand.

Conditions affecting the nervous system

 * Amyotrophic lateral sclerosis (Lou Gehrig's disease)
 * Lumbar radiculopathy (L4 and L5 nerve roots)
 * Spinal disc herniation
 * Multiple Sclerosis
 * Peripheral neuropathies: Multifocal motor neuropathy (foot drop may be the presenting symptom), diabetic neuropathy
 * Common peroneal nerve palsy
 * Charcot-Marie-Tooth disease (peroneal muscular atrophy)
 * Progressive spinal muscular atrophy
 * Poliomyelitis
 * Leprosy
 * Compartment syndrome
 * Human monocytic ehrlichiosis (long term manifestation)
 * Cryoglobulinemia

Conditions affecting the musculature

 * Different kinds of muscular dystrophy (Duchenne muscular dystrophy, Facioscapulohumeral dystrophy, scapuloperoneal muscular dystrophy, Myotonic dystrophy, desmin myopathy,
 * Inclusion body myositis

Drugs

 * Vincristine (adults more severely affected than children) (Adams and Victor)
 * Auranofin
 * Allopurinol (causal relationship not established)
 * Glatiramer (uncommon)
 * Chymopapain (uncommon)
 * Thalidomide (uncommon)

Toxins

 * Lead neuropathy (usually presents with wrist and finger drop, foot drop less common) (Adams and Victor)

Treatment
The underlying disorder must be treated. For example, if a spinal disc herniation in the low back is impinging on the nerve that goes to the leg and causing symptoms of foot drop, then the herniated disc should be treated.

Ankles can be stabilized by lightweight orthoses, and shoes can be fit with springs to prevent foot drop while walking. Regular exercise is usually prescribed.

The latest treatments include stimulation of the peroneal nerve that lifts the foot when you step. Many stroke and multiple sclerosis patients with foot drop have had success with it.

Devices have also been designed to regulate walking.