Restless legs syndrome (RLS) is a neurological disorder characterized by an irresistible urge to move one’s legs, often accompanied by uncomfortable sensations such as creeping, crawling, or tingling. The condition affects up to 15 percent of the US population but is more common among people with multiple sclerosis (MS) – suggesting a potential link between the two conditions.
Understanding RLS
RLS is a disorder that can have a significant impact on a person’s quality of life. The sensations associated with RLS typically occur in the legs, but can also affect other parts of the body, such as the arms or torso. These sensations often occur at night or during periods of inactivity or rest.
The exact cause of RLS is not known, but research suggests that it may be related to abnormalities in the levels of certain neurotransmitters in the brain, such as dopamine and iron. Although up to 90 percent of RLS cases are genetic, other factors have also been implicated in its development. These include:
- Hormonal changes
- Nutritional deficiencies
- Pregnancy
- Smoking
- Medications (such as certain antidepressants and antipsychotics)
- Alcohol or drug abuse
- Certain medical conditions, such as multiple sclerosis or kidney disease
What is Multiple Sclerosis?
Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system, leading to inflammation and damage to the myelin sheath that surrounds nerve fibers. Symptoms of MS may include ongoing pain, loss of bowel or bladder control, chronic fatigue, poor vision, motor dysfunction, sexual problems, poor mood, cognitive decline (brain fog), muscle spasms and stiffness, and tingling/numbness in the extremities.
A recent study has shown that there is a strong association between RLS and MS, with a significantly higher prevalence of RLS among people with MS compared to those without the disease.
Just How Common Is RLS in Multiple Sclerosis?
In a case-control study published in the Journal of Multiple Sclerosis and Related Disorders, nearly one-quarter of people with MS involved in the study experienced RLS, compared with less than 4% in people without the disease. The study involved 235 participants (117 of whom had MS) and found that the prevalence of RLS in people with MS was 23.9 percent, compared with 3.4 percent in the control group.
The study also found that people with MS who experienced RLS had more severe MS symptoms, such as fatigue, depression, and anxiety, compared to those without RLS. In addition, people with both MS and RLS had significantly worse sleep quality and more severe fatigue and daytime sleepiness compared to those with MS alone.
Examining the Connection Between RLS and Multiple Sclerosis
Although there is no definitive answer to why RLS is more common in people with MS, there are several theories that try to explain the high rate of comorbidity. One theory suggests that it may be related to abnormalities in the neurotransmitters dopamine and iron. MS is an autoimmune disease in which the immune system mistakenly attacks healthy nerve cells, resulting in inflammation and damage to the myelin sheath surrounding the neurons.
This damage can disrupt communication between the brain and other parts of the body, leading to the dysregulation of certain neurotransmitters, including dopamine. This disruption may be a contributing factor in RLS development among people with MS.
Additionally, iron deficiency is also common among people with MS and could be linked to RLS development. Iron plays an important role in the production of dopamine, and a lack of iron can lead to reduced levels of this neurotransmitter.
Last but not least, some experts believe that RLS may also be linked to the nerve damage associated with MS. This damage can lead to an imbalance in the normal nerve signals that control muscle movement and coordination, resulting in RLS symptoms such as involuntary jerking and twitching.
Impact of RLS on Multiple Sclerosis
For people with MS, the impact of RLS can be particularly significant. MS symptoms such as muscle spasms, weakness, and numbness can be exacerbated by RLS, making it more difficult to manage symptoms and maintain mobility. The fatigue and sleep disturbances associated with both MS and RLS can also have a compounding effect, leading to a further decline in quality of life.
Final Thoughts
Although the underlying mechanisms are still unclear, it is clear that there is a strong connection between RLS and MS, and more research into this comorbidity is needed to uncover more information about the relationship between the two conditions. In the meantime, healthcare providers need to screen for RLS in people with MS in order to provide a comprehensive treatment plan and improve quality of life for patients.