So the patient goes to a neurologist.
Every night, he tells the doctor, he gets these creepy, crawly feelings in his legs as he starts to drift off to sleep. It's not pain, exactly, but an irresistible urge to move his legs. He gets up, does a few deep knee bends. That helps. The neurologist listens, riveted.
But as soon as the patient goes back to bed, the creepy-crawlies start up again. Sometimes, his legs start kicking periodically too. So he gets up and walks, for hours, until exhaustion overwhelms his twitchy legs and frazzled psyche. With luck, he gets a few hours sleep.
"What have I got?" the frustrated patient asks. "I don't know," the doctor replies. "But I've got it too."
Sad to say, this is a true story, told by a patient to Dr. John Winkelman, medical director of the Sleep Health Center at Boston's Brigham and Women's Hospital. Most people, including many doctors, have never heard of restless legs syndrome, though this under-diagnosed neurological disorder ruins the sleep -- and the quality of life -- of an estimated 20 million Americans.
"But people are going to hear a lot more about this disorder in the next couple of years," says Winkelman, "because we now recognize how common it is and we're beginning to get some insights into its underlying causes."
Scientists haven't filled in all the blanks, but they have a pretty good idea of what goes wrong in the brains of people with restless legs syndrome, thanks to brain scans and autopsies of RLS sufferers.
In the brain, the substantia nigra, the caudate nucleus and the putamen -- all of which control movement -- appear to be somewhat deficient in iron. That may impair the ability of brain cells to make the neurotransmitter dopamine, says Dr. Wayne Hening, clinical associate professor of neurology at the Robert Wood Johnson Medical School in New Jersey.
The result is creepy-crawly sensations in the legs and the urge to move the legs. These symptoms come on with rest or immobility and are relieved -- transiently -- by movement.
Many people with restless legs syndrome also have what's known as "periodic limb movements of sleep," uncontrollable kicking during sleep.
Possible genetic factor
Though not fatal, restless legs syndrome is a life-wrecker. It often runs in families, suggesting a possible genetic factor, and can start in childhood.
"These people can't relax. They're tired all the time," says Jerry Siegel, professor of psychiatry at UCLA's Neuropsychiatric Institute and chief of neurobiology research at the Sepulveda VA hospital.
"Of all the disorders affecting sleep, this is the one that produces the most chronic sleep loss year after year," says psychologist Richard Allen of the Johns Hopkins Center for Restless Legs Syndrome in Baltimore. His research shows that "quality of life is as impaired in these patients as in patients with other chronic diseases like hypertension, arthritis, diabetes, depression, angina or a history of heart attack."
Decades of insufficient sleep is just plain "discouraging," says Marge Fuhr, 67, a retired school teacher in Boulder, Colo. "I'm just totally exhausted."
For Mimi LeBien, 43, a self-employed medical historian in Covington, La., the worst part is the sense of "shame that comes with people who can't sleep." Like Fuhr, LeBien is a board member of the Restless Legs Syndrome Foundation. Her struggle with RLS began when she was 7 or 8, on a long family car trip when she made her brother and sister lie down on the floor of the backseat because "I needed to kick and kick and kick ....I kicked my legs halfway across New Mexico."
Spouses suffer too. Tim Bemis, 42, a software engineer who lives in Bedford, Mass., used to get only two to three hours sleep a night. Now, he takes medications for his RLS and periodic leg movements and sleeps six or seven hours. In the old days, says his wife, Anita Raj, 41, "he used to move every six seconds. I used to count 'one one thousand, two one thousand ... ' It would keep me awake." Even now, she says, "there are probably 10 nights a month where we sleep in separate beds."
So what to do if you are among the millions with possible RLS? First, if your regular doctor can't help, contact a neurologist or sleep clinic. You'll probably be given blood tests for iron levels. If these tests show low iron in your blood, taking oral iron (ferritin) may help. (Don't do this on your own. If you take too much iron, you can develop a dangerous condition called hemochromatosis, or iron overload, which can cause cardiac and other problems.)
If your blood test is normal, however, you may still be iron-deficient in the brain. In this case, oral iron probably won't help, but researchers are trying to determine whether giving RLS patients iron intravenously will.
The low iron levels that can lead to restless legs syndrome can have several triggers, including any condition that leads to persistent anemia. Pregnancy, stomach surgery, kidney failure and dialysis also can contribute.