foot drop in multiple sclerosis

Multiple sclerosis (MS), a progressive neurological disorder, is characterized by the immune system mistakenly attacking the protective protein coating that surrounds nerve fibers, the so-called myelin sheath. Without this protection, nerve fibers are fragile and easily damaged, and eventually die.

The loss of nerve cells leads to the many symptoms of MS, including muscle weakness and spasms, fatigue, and problems with walking and balance. While symptoms may vary among individuals and across the different types of MS, one symptom that can be common to many patients is foot drop.

What is foot drop?

Foot drop occurs when a person lifts their foot while walking: instead of the toes lifting with the step, they drop, dragging on the ground. Foot drop makes it much more likely that patients will trip and fall while walking, especially on uneven surfaces like stairs.

Many people compensate by lifting their foot higher when walking, but this makes even short walks much more tiring. An odd gait can also lead to back and hip pain. And this gait can make patients more wobbly while walking, meaning they are more likely to stumble and fall.

Foot drop can also make other many aspects of daily life more challenging. Patients may have difficulty driving, for instance, because it can be hard to press on the vehicle’s foot pedals.

What causes foot drop?

Foot drop is caused by weakness in the ankle, largely due to a slowing or block in communication between nerves in the brain and the foot. Messages sent along nerve pathways that are interrupted or out of sync affect coordination between the leg and the ankle while walking. Normally, when taking a step, the muscles of the ankle tighten, keeping the toes tucked up during the step and relaxing when the heel touches the ground. Poor muscle coordination means that the toes are not kept at the proper angle when taking a step.

Other MS symptoms can also worsen foot drop. Loss of myelin affects nerve signaling, which can make it difficult to control movement of the legs and feet. Many patients have numbness or a frequent “pins-and-needles” tingling sensation in their hands and feet, making it harder for the brain to manage proprioception — the ability to sense where the limbs are at rest or in motion. Since the brain relies on sensations to coordinate limb movement, difficulties in managing proprioception make walking much more challenging.

 

Last updated: Oct. 23, 2019

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Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.