Causes of Restless Leg Syndrome
Cause of restless leg syndrome is unknown in most patients; however, stress appears to make the condition worse. Restless leg syndrome can be primary or secondary.
Secondary restless legs syndrome causes by an underlying medical condition.
Primary (idiopathic) RLS has no known underlying cause. Primary restless leg syndrome is far more common than secondary restless leg syndrome.
Primary restless legs syndrome causes are unknown, but some of the risk factors are known.
- In 25-75% of cases, primary restless leg syndrome seems to run in families. Such hereditary cases of restless leg syndrome tend to start earlier in life and get worse more slowly than other cases.
- Psychiatric factors, stress, and fatigue can worsen the symptoms of restless leg syndrome.
- Many different medical conditions can cause secondary restless leg syndrome.
- The two most common causes of restless leg syndrome are iron-deficiency anemia and peripheral neuropathy.
- Iron-deficiency anemia ("low blood") means low levels of hemoglobin, the substance in the blood that carries oxygen and makes the blood appear red.
- Peripheral neuropathy is damage to the nerves of the arms and legs. Peripheral neuropathy has many causes. Diabetes is a common cause of peripheral neuropathy. Peripheral neuropathy causes numbness or lack of sensation, tingling, and pain in the affected areas.
- As many as 40% of pregnant women experience restless leg syndrome symptoms. The symptoms usually fade within a few weeks after delivery.
- Family History – Restless leg syndrome does seem to run in families, although a genetic origin has not been discovered.
- Withdrawal from vasodilator drugs, sedatives, or imipramine is also a cause of restless leg syndrome symptoms.
- Cigarette smoking is the cause of restless leg syndrome.
- Certain medications or substances are also the causes of restless leg syndrome. Alcohol, caffeine, anticonvulsant drugs (eg, methsuximide, phenytoin), antidepressant drugs (eg, amitriptyline, paroxetine), H2 blockers, lithium, beta-blockers and neuroleptics (antipsychotics) may cause RLS.
- Caffeine, alcohol, and tobacco use –consuming caffeine, alcohol, and tobacco is also the cause of restless leg syndrome.
- Other secondary causes of restless leg syndrome include vitamin B-12 deficiency, magnesium deficiency, severe kidney disease (especially if dialysis is required), amyloidosis, Lyme disease, damage to the spinal nerves, rheumatoid arthritis, Sjögren syndrome, and uremia (kidney failure causing build up of toxins within the body).
In most people with restless legs syndrome (RLS), poor sleep and daytime sleepiness are the most bothersome symptoms. Many people do not link their sleep problem with the strange sensations in their legs.
If you are having these sensations, be sure to mention it to your health care provider. This provides a very important clue to what is causing you to sleep poorly. Sleep disturbances have many different causes. Your health care provider may ask you many detailed questions.
These questions concern current medical problems, prior medical problems, family medical problems, medications, work history, travel history, personal habits, and your lifestyle. Your health care provider will look for signs of an underlying cause for your sleep problem.
There is no lab test or imaging study that can prove that you have RLS. However, certain tests can identify underlying medical cause of restless leg syndrome such as anemia, other deficiencies, and metabolic disorders that are the causes restless leg syndrome.
- You may have blood drawn to check your blood cell counts and hemoglobin, basic organ functions, chemistry, and thyroid hormone levels. You also may be checked for certain infections that could cause secondary restless leg syndrome.
- Needle electromyography and nerve conduction studies may be done if your health care provider sees signs of neuropathy.
- Polysomnography (sleep testing) may be necessary to diagnose the sleep disturbances and determine if you have periodic limb movements. This is especially important in people who continue to have significant sleep disturbances despite relief of