Causes and Triggers of Restless Legs Syndrome in Multiple Sclerosis (MS)

Restless legs syndrome (RLS) is a sleep-related movement disorder commonly experienced by people with multiple sclerosis (MS). RLS causes spontaneous, jerking leg movements that can disrupt sleep and contribute to fatigue in people with MS.

Research shows that people with MS are six times more likely to have RLS than people in the general population. They also tend to experience RLS symptoms worse. Iron deficiency and chronic inflammation are thought to be contributing factors.

The article describes the causes and triggers of restless legs syndrome in people with MS. It also explains how RLS differs if you have MS and what is involved in the diagnosis and treatment of this common MS symptom.

Symptoms of Restless Legs Syndrome

RLS is a sleep-related movement disorder characterized by unpleasant leg sensations that cause you to move your legs impulsively (called periodic leg movements).

These sensations are often described as:

• Aching
• Tugging
• Twitching
• Itching
• Tingling
• Shock-like
• Tightening
• Like "bugs crawling under the skin"

In people with multiple sclerosis, the symptoms typically occur at night, leading to insomnia and sleep deprivation. The resulting fatigue (called "secondary fatigue") can complicate the primary fatigue caused by the damaging effects of MS on the brain.

What makes RLS unusual in people with MS is that it tends to improve with movement.

What Causes Restless Legs Syndrome With MS?

RLS affects roughly a quarter of people with MS, compared to 6% of people without MS. The disparity is thought to be caused by the effects MS has on the nerves of the spinal cord.

Multiple sclerosis is an autoimmune demyelinating disease. This is a disorder in which the immune system mistakenly attacks and damages the protein coating of nerve cells, called myelin. When this happens, nerve cells can "misfire" and disrupt normal nerve signaling to the brain.

When peripheral nerves emerging from the spinal cord are affected, it can cause abnormal sensations like burning and tingling called neuropathy. But when it happens with central nerves of the brain and spinal cord, it can trigger abnormal movements and sensations.

Studies suggest that nerve demyelination in the cervical spinal cord of the neck is the main cause of RLS in people with MS. This is especially true when multiple spinal cord lesions are found.

The lesions appear to block the signals of an important neurotransmitter called dopamine which helps regulate leg muscle movements. Chronic inflammation (a hallmark of MS) can also contribute by releasing inflammatory chemicals called cytokines that irritate the spinal cord.

How Restless Leg Syndrome Differs With MS

Restless legs syndrome manifests differently in people with MS. The condition can be diagnosed when the following criteria are met:

• The urge to move your legs is accompanied by uncomfortable sensations.
• This urge to move gets worse when lying still or sitting.
• Moving eases the unpleasant sensations and urge to move.
• The urge to move is much worse at night than during the day.

This differs considerably from how RLS affects people without MS.

Other Leg Symptoms With MS

Multiple sclerosis can cause other leg symptoms that can be confused for or accompany RLS. These include:

• Extensor spasms: This is the involuntary stiffening of the leg muscles accompanied by the inability to bend your knee. It usually affects the quadriceps (thigh muscles), causing the lower leg to jerk outward and lock at the knee.
• Dysesthesia: These are unpleasant nerve sensations characterized by burning, numbness, tingling, or aching in the legs, arms, hands, feet, or torso. The sensations last for only a few seconds or minutes and are typically bilateral (affecting both sides of the body at once).

How Is Restless Legs Syndrome Treated or Managed?

Restless legs syndrome can be challenging to treat because certain treatments work for some people but not for others. Even so, there are several home remedies and medical treatments you might consider if RLS is causing distress.

Home Remedies

Depending on how often and severely your restless legs syndrome acts up, the following home remedies may help:

• Exercise moderately most days of the week, including walking or cycling.
• Reduce your caffeine intake.
• Get a leg message, including a technique known as pneumatic compression.
• Take a lukewarm bath.
• Increase your iron intake with foods (like liver or spinach) or iron supplements.

Medications

If home remedies don't help, speak with your healthcare provider. They may be able to prescribe drugs that can ease RLS. Some of these may help with other MS symptoms, such as dysesthesia.

Among them:

• Benzodiazepines such as Valium (diazepam) and Klonopin (clonazepam) have been known to help people with RLS but may worsen fatigue.
• Medications called dopamine receptor agonists may increase dopamine in the brain. These include Requip (ropinirole) and Mirapex (pramipexole).
• Neurontin (gabapentin) is an anticonvulsant drug often used to treat neuropathy common in people with MS. It may also help with RLS.

Summary

Restless legs syndrome (RSL) is a sleep-related disorder that causes impulsive leg movements. RLS occurs six times more frequently in people with multiple sclerosis (MS) than those without. It is thought to be due to MS lesions that develop on the spinal cord. Iron deficiency and chronic inflammation may also contribute.

While no treatment for RLS works for all people, moderate exercise, a reduction in caffeine, and iron supplements may help. If these fail to provide relief, ask your healthcare provider about prescription medications that may help ease RLS symptoms as well as other MS symptoms.