Restless Leg Syndrome (RLS) once fell into a category that might be called "orphan diseases" – strange, hard-to-describe symptoms, no apparent threat to life or overall health, often dismissed as patient imagination or a symptom of something else by doctors who had never heard of it.

In the past year or so, however, an extensive TV ad campaign began for a new drug, designed specifically to deal with RLS. Whatever the merits of the product, the ads have brought the ailment into the light and given sufferers the courage to talk about it.

But while everyone now seems to have heard of RLS, many still find its symptoms odd, even funny – leaving those who have it fully aware it remains largely misunderstood.

RLS got its name from the unbearable urge sufferers have to move their legs while trying to sleep at night. The need is brought on by what are variously described as tingling or prickling sensations or insects crawling under the skin. Perhaps one of the best descriptions to help non-RLS patients understand is that it is similar to the feeling that some people get that requires them to crack their knuckles – except sufferers feel it in every joint and muscle and there is nothing to "crack" to relieve it.

As discomforting as traditional RLS is, a variant is even worse, extending beyond the legs to afflict fingers, hands and arms, as well.

Although often dismissed as harmless, RLS can create a multitude of problems, the most common being extreme fatigue caused by the inability to sleep. It is not uncommon for RLS patients to stay awake for 24 to 36 hours – or more – because the constant need to move, to stretch, to "crack" makes it impossible for them to sleep. Until sheer exhaustion overwhelms them and they simply pass out. Even then, their bodies often continue to struggle against the affliction, keeping them from reaching the level of deep sleep they need for true rest.

Fatigue leads to irritability and lack of concentration, affecting their ability to do their jobs, learn in the classroom, watch over their children, perform tasks requiring sharp attention and quick reaction, such as driving. As a result, this "silly" complaint can ruin lives and even endanger the patient and others.

The National Institute of Neurological Disorders and Stroke (NINDS) at the federal National Institutes of Health says estimates of the number of RLS sufferers in the United States alone range from 12 million to perhaps many times that number. The exact number – or even a reasonable estimate – is clouded by cases that are either misdiagnosed or simply unreported by patients who have themselves fallen victim to the "silly" complaint label.

To date, medical researchers have been unable to determine the cause for RLS, which appears to have no preference for age, sex, race, occupation, etc., although severity and frequency do increase with age. Research does indicate a possible genetic factor, as about half of RLS patients report a family history of the ailment. It also is often associated with pregnancy, kidney failure, diabetes, Parkinson's disease and peripheral neuropathy and may be aggravated by caffeine, alcohol and tobacco.

There is no single diagnostic test for RLS; instead, diagnosis typically results from patient descriptions of the symptoms to a doctor familiar with the affliction. A reluctance to even discuss it by patients and little or no knowledge of it by doctors makes the extent of its presence in nations with lower levels of medical care even more difficult to ascertain.

Without a known cause, doctors are forced to treat the symptoms, usually prescribing drugs originally developed for Parkinson's, although some progress has been made recently on pharmaceuticals specifically designed for RLS. While these treatments generally bring some relief, most patients eventually develop "augmentation" – symptoms may lessen at night, only to appear instead during the evening or daytime hours. And, in some cases, increasing dosage of the drug may even backfire, actually increasing the severity and length of an attack.

NINDS is leading the federal effort to find the cause and an effective treatment for RLS, most recently focusing on a possible relationship to dopamine, a chemical that helps transmit signals within the brain.

For now, however, RLS remains a mystery, with no known cause, no effective long-term treatment, no cure and, despite increasing awareness, little understanding of its impact on the lives of sufferers from those around them. About the most doctors can do today is encourage those who have experienced the basic symptoms – an uncontrollable need to move their limbs when laying down to rest – to take it seriously and talk to their doctors.

More information about Restless Leg Syndrome can be found online at...

ninds.nih.gov/disorders/restless_legs/detail_restless_legs.htm

and the Mayo Clinic at...

mayoclinic.com/health/restless-legs-syndrome/DS00191