What Causes Restless Leg Syndrome?

Hypothyroidism Or Hyperthyroidism

Hypothyroidism or hyperthyroidism and restless leg syndrome often occur together because both conditions are associated with dopaminergic dysfunction. In a study of patients with thyroid conditions, 8.2 percent reported having symptoms similar to those described in RLS. By comparison, the control group without thyroid conditions only have a 0.9 percent prevalence of restless leg symptoms. One-third of the thyroid patients reported their RLS symptoms became completely resolved after their thyroid condition was treated.

Hypothyroidism is caused by the thyroid failing to make enough hormones. The condition can also cause depression and slow metabolism. On the other hand, hyperthyroidism occurs when the thyroid is overactive and creates too many hormones. This can lead to an overactive metabolism and potentially serious symptoms.

Rheumatoid Arthritis

Rheumatoid arthritis has been associated with restless legs syndrome. Studies indicate RLS might occur in around ten to fifteen percent of the population in the United States. Almost one-third of restless leg syndrome patients also have rheumatoid arthritis. One theory for why these conditions occur alongside each other so often is because of iron deficiency. The brain produces a chemical called dopamine, which is essential to the health of an individual's immune system and central nervous system. Dopamine needs iron to function properly. Many of those with RLS symptoms also have low iron levels, which means dopamine isn't functioning as effectively in the brain. Rheumatoid arthritis can affect the amount of iron in the brain or the ability to use iron in the brain.