Nerve Cells May Be the Key to Understanding the Cause of Restless Leg Syndrome

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Researchers say these cells may become overactive in people with this condition.
It affects 1 in 10 adults and, until recently, the drugs most commonly prescribed for it made the ailment worse over the long run.
For sufferers of restless leg syndrome, an uncontrollable urge to move their legs can constantly interrupt their sleep, if they manage to get to sleep at all.
New drugs have emerged to help treat the condition, but the medications are often borrowed from other conditions and have drawbacks.
Part of the problem with developing better drugs is that researchers don’t yet have a complete picture of why people get restless legs.
“It’s a condition that we know how to fix and we know who has got it, but there’s still a lot of work to be done in terms of figuring out why people get it,” Dr. Nitun Verma, a sleep medicine specialist and spokesman for the American Academy of Sleep Medicine, told Healthline.
That picture was fleshed out a bit more this month.
A new study found that nerve cells in the legs can have heightened excitability in patients with restless legs.
Finding drugs that can target the communication between those cells and bring the signals down to normal levels could be a new way of trying to prevent restless legs.
That can cause those cells to fire out an abnormally high number of signals to each other.Causes and treatments
A number of factors have been blamed for restless leg syndrome — often called by those who work on it “the most common condition you have never heard of.”
Those causes include genetics, iron deficiency, certain medications and stimulants, an imbalance of chemicals in the brain, and pregnancy.
The symptoms seem to start in the brain, not in the legs.
People can get that uncontrollable, difficult-to-ignore urge to move their legs even if they have lost their legs, said Dr. Mark Buchfuhrer, a sleep specialist at Stanford’s Restless Legs Syndrome Clinic, told Healthline.
So, most treatments for restless legs focus on the brain and are borrowed from other conditions that affect the brain.
Buchfuhrer said four drugs are approved for restless legs, and two of those are in a class of drugs — dopamine agonists — that are given to patients with Parkinson’s disease.
“Those were the go-to drugs 10, 15 years ago,” he said. “But the vast majority of patients using those drugs will get a worsening of restless legs in about 10 years, and it becomes markedly more difficult to treat.”
That worsening, he said, can occur so slowly that physicians may not tie it to the drugs and may prescribe even more of them, which can just make things worse in the long run.