Printer-friendly format

Perhaps nothing is more frustrating to a medical scientist than an idiopathic diagnosis. Even when physicians have tools to treat the symptoms of a disorder, not knowing the cause can make it a tedious undertaking.

The phenomenon of Restless Legs Syndrome (RLS) continues to perplex in that way, but increased awareness and pharmaceuticals are providing more relief than ever to those who suffer from this unpleasant neurological disorder.

An estimated 5 to 15 percent of the general population of the Western World suffers from RLS, according to Dr. Morris T. Bird, 67, director of the Center for Sleep Disorders at Florida Hospital and board-certified in sleep medicine and neurology. “It’s a fairly common problem that has been around forever. It hasn’t justified much attention from medical practitioners up until recently, the reason being there wasn’t a treatment,’’ Bird said. “Today, there are a number of treatments that are pretty good.’’

RLS is characterized by unpleasant sensation in the legs and an uncontrollable urge to move when at rest, according to the National Institute of Neurological Disorders and Stroke (NINDS). Patients complain of burning, creeping or stinging feelings, most often distally rather than proximally. For inexplicable reasons, the sensations usually occur just before bedtime, making it difficult to fall asleep. Sleep deprivation creates even more problems for the patient, such as daytime fatigue, exhaustion, impaired memory and an inability to concentrate.
RLS is often misdiagnosed, or at least underdiagnosed, according to the NINDS. Many sufferers will not seek medical attention for what they believe are mild symptoms that they attribute simply to nervousness. And for those who do relate their symptoms to primary care physicians, it often is dismissed as stress, muscle cramps or arthritis.

Because there is no specific diagnostic test to ascertain RLS, front-line doctors must rely on their clinical skills to obtain the appropriate history of patients who present with symptoms.

One of the first things doctors can do is try to determine the difference between RLS and Periodic Limb Movement Disorder (PLMD). PLMD is characterized by involuntary twitching or jerking movements that occur during sleep. RLS is “a disturbance of wakefulness, not a disturbance of sleep,’’ said Bird, but both result in “decreased sleep quantity.’’

Dr. Robert A. Hauser, a professor of neurology at the University of South Florida in Tampa, concurs. “Although PLMD is commonly seen in RLS patients about 80 percent of the time, it is not 100 percent, so you go by the clinical history. Don’t depend on getting a sleep test that shows periodic limb movements. It is not necessary,’’ Hauser said.

Still, RLS has some common denominators. “About 50 percent of the patients with RLS appear to have a familial component,’’ said Hauser, and “the younger a person is when they get it, the more likely they are to have that familial component,’’ he said. “That fits in well with what we see in other genetic diseases; generally the younger you are when you get it, the more likely you are to have a genetic cause.’’

Iron deficiency is another indicator of RLS. “It certainly appears that low iron is a cause of RLS,’’ Hauser said, and “there appear to be some connections between low iron and (low) dopamine. We don’t know what that really means, but there is no question that many patients with RLS also have a low-iron status.’’
Bird said: “If we see a patient with RLS, we’ll run the serum iron and other iron-binding studies, and we’ll treat it with iron. That sometimes is very helpful,’’ but being careful to avoid the possibility of iron overload.

Treatment of RLS saw a breakthrough about five years ago with the Federal Drug Administration’s approval of the dopamine agonist Requip, and the subsequent approval of Mirapex. Both drugs affect the brain chemical that helps control motor functions and are effective medication therapies. “The new kid on the block is Neupro,’’ which has not yet received FDA approval for RLS and is used in a transdermal patch primarily to treat patients with Parkinson’s disease, said Hauser.

Once a patient who is diagnosed with RLS begins taking the dopamine agonists, they most likely will need to continue it, said Hauser, 50. “Many (RLS) patients don’t need it every night. When it gets worse they do. If it is helping, they will stay on it. It’s not like they take it and in two months the disease goes away,’’ he said. “Typically, they need these drugs on an ongoing basis.’’ The drugs “appear to be very effective,’’ he said, “but it does not cure the underlying disease.

The onset of RLS increases with age, and so can the intensity of symptoms. “It’s typically middle-adulthood,’’ Hauser said, “and the symptoms do worsen over time.’’ It also afflicts more women than men, but that is partially due to the transient occurrence of symptoms in pregnant women, who no longer experience them after they give birth.

Also, according to the NINDS, researchers have found that caffeine, alcohol and tobacco may have a negative effect on patients who are predisposed to RLS. Yet, there is no evidence that curbing those indulgences can actually prevent the symptoms of RLS.

The most reliable approach to diagnosing RLS is to “listen to the patient,’’ said Bird, taking careful note of family and childhood histories. When the symptoms of RLS “prevent sleep entrance,’’ which can trigger more acute medical problems, Bird said, then that is when primary care physicians need to be tuned in to this enigmatic malady.



April 2008

Tags:

None

Login and voice your opinion!