These symptoms of restless legs syndrome can range from "barely noticeable to almost incapacitating," according to Buchfuhrer. Some people have minor symptoms and no sleep problems. The most severely affected suffer almost constant discomfort or pain for years, if untreated.
People with restless legs syndrome typically come to the doctor complaining of insomnia or fatigue. Often, "their sleep is quite disrupted," says Buchfuhrer. The chronic fatigue caused by restless legs syndrome can create other problems:
"People with moderate-to-severe restless legs syndrome can become totally disabled," says Buchfuhrer. In the most severe cases, he adds, "They can't sit down to work. They eat breakfast walking around the room." Many avoid movies, car trips, or plane rides, knowing their symptoms might make the activity intolerable.
Fortunately, restless legs syndrome does not lead to other neurological conditions, such as Parkinson's disease or neuropathy. However, "this is a progressive disorder that -- in most people -- gets worse over time," says Buchfuhrer.
Most people with restless legs syndrome also have periodic limb movement disorder. In this condition, involuntary twitching of the arms and legs disrupts sleep. Periodic limb movement disorder can contribute to the chronic fatigue of RLS.
Restless Legs Syndrome: What Causes It?
Experts aren't sure what causes restless legs syndrome. According to James Connor, PhD, distinguished professor and vice chairman in the Department of Neurosurgery at Penn State University, however, new research shows that iron plays a key role.
Magnetic resonance imaging (MRI) scans and brain tissue studies from deceased restless legs syndrome patients demonstrate reduced amounts of iron in their brains compared with non-RLS patients' brains. This occurs even when the level of iron in the blood is okay.
"Many people with restless legs syndrome are 'brain-iron-deficient,' even if their whole-body iron levels are normal," says Connor.
Researchers also know that dopamine is a key player in restless legs syndrome. Dopamine, a neurotransmitter, relays messages between nerve cells in the brain.
In those with RLS, "there appears to be compromised uptake of iron into the [nerve] cells in the brain that make dopamine," says Connor. This could lead to decreased function of these nerve cells, including the ability to make dopamine, he adds.
The disorder runs in families, with about half of restless legs syndrome sufferers having family members affected as well.
Most cases of restless legs syndrome are unexplained, or "idiopathic." Sometimes RLS is associated with other medical conditions:
Treating these conditions, if present, can improve restless legs syndrome symptoms.