Restless Legs Syndrome (RLS) is a movement disorder that results in an unpleasant sensations in the legs and an uncontrollable urge to move when at rest in an effort to relieve these feelings. These symptoms occur primarily and night and can disrupt sleep.
The sensations of Restless Leg Syndrome are often described by people as burning, creeping, tugging, or like insects crawling inside the legs. Often called paresthesias (abnormal sensations) or dysesthesias (unpleasant abnormal sensations), the sensations range in severity from uncomfortable to irritating to painful.
The most distinctive or unusual aspect of the condition is that lying down and trying to relax activates the symptoms. As a result, most people with Restless Leg Syndrome have difficulty falling asleep and staying asleep. Left untreated, the condition causes exhaustion and daytime fatigue. Many people with Restless Leg Syndrome report that their job, personal relations, and activities of daily living are strongly affected as a result of their exhaustion. They are often unable to concentrate, have impaired memory, or fail to accomplish daily tasks.
Restless Leg Syndrome occurs in both men and women though it is slightly more common among men. Most people affected are middle-aged or older. The severity of symptoms appears to increase with age and older patients experience symptoms more frequently and for longer periods of time.
More than 80% of people with Restless Leg Syndrome also experience a more common condition known as periodic limb movement disorder (PLMD). PLMD is characterized by involuntary leg twitching or jerking movements during sleep that typically occur every 10 to 60 seconds, sometimes throughout the night. The symptoms cause repeated awakening and severely disrupted sleep. Unlike Restless Leg Syndrome, the movements caused by PLMD are involuntary-people have no control over them. Although many patients with Restless Leg Syndrome also develop PLMD, most people with PLMD do not experience Restless Leg Syndrome. Like RLS, the cause of PLMD is unknown.
What are the symptoms of Restless Leg Syndrome?
Because moving the legs (or other affected parts of the body) relieves the discomfort, people with Restless Leg Syndrome often keep their legs in motion to minimize or prevent the sensations. They may pace the floor, constantly move their legs while sitting, and toss and turn in bed.
Most people find the symptoms to be less noticeable during the day and more pronounced in the evening or at night, especially during the onset of sleep. For many people, the symptoms disappear by early morning, allowing for more refreshing sleep at that time. Other triggering situations are periods of inactivity such as long car trips, sitting in a movie theater, long-distance flights, immobilization in a cast, or relaxation exercises.
The symptoms of Restless Leg Syndrome vary in severity and duration from person to person. Mild cases occurs episodically, with only mild disruption of sleep onset, and causes little distress. In moderately severe cases, symptoms occur only once or twice a week but result in significant delay of sleep onset, with some disruption of daytime function. In severe cases, the symptoms occur more than twice a week and result in burdensome interruption of sleep and impairment of daytime function.
What causes Restless Legs Syndrome?
In most cases, the cause of Restless Leg Syndrome is unknown (referred to as idiopathic). About one-half of people affected will have a family member with the condition.
In other cases, Restless Leg Syndrome appears to be related to the following factors or conditions, although researchers do not yet know if these factors actually cause RLS.
- People with low iron levels or anemia may be prone to developing Restless Leg Syndrome. Once iron levels or anemia is corrected, patients may see a reduction in symptoms.
- Chronic diseases such as kidney failure, diabetes, Parkinson's disease, and peripheral neuropathy are associated with Restless Leg Syndrome. Treating the underlying condition often provides relief from Restless Leg Syndrome symptoms.
- Some pregnant women experience Restless Leg Syndrome, especially in their last trimester. For most of these women, symptoms usually disappear within 4 weeks after delivery.
- Certain medications-such as antinausea drugs (prochlorperazine or metoclopramide), antiseizure drugs (phenytoin or droperidol), antipsychotic drugs (haloperidol or phenothiazine derivatives), and some cold and allergy medications-may aggravate symptoms. Patients can talk with their physicians about the possibility of changing medications.
Caffeine, alcohol, and tobacco may aggravate or trigger symptoms in patients who are predisposed to develop Restless Leg Syndrome. Some studies have shown that a reduction or complete elimination of such substances may relieve symptoms, although it remains unclear whether elimination of such substances can prevent Restless Leg Syndrome symptoms from occurring at all.
How is Restless Legs Syndrome diagnosed?
Despite a clear description of clinical features, the condition is often misdiagnosed or underdiagnosed. In 1995, the International Restless Legs Syndrome Study Group identified four basic criteria for diagnosing Restless Leg Syndrome:
- A desire to move the limbs, often associated with paresthesias or dysesthesias
- Symptoms that are worse or present only during rest and are partially or temporarily relieved by activity
- Motor restlessness
- Nocturnal worsening of symptoms.
Although about 80% of those with Restless Leg Syndrome also experience PLMD, it is not necessary for a diagnosis of RLS.
Despite these efforts to establish standard criteria, the clinical diagnosis of RLS is difficult to make. Physicians must rely largely on patients' descriptions of symptoms and information from their medical history, including past medical problems, family history, and current medications.
If a patient's history is suggestive of RLS, laboratory tests may be performed to rule out other conditions and support the diagnosis of RLS. Blood tests to exclude anemia, decreased iron stores, diabetes, and renal dysfunction should be performed.
Electromyography and nerve conduction studies may also be recommended to measure electrical activity in muscles and nerves, and Doppler sonography may be used to evaluate muscle activity in the legs. Such tests can document any accompanying damage or disease in nerves and nerve roots (such as peripheral neuropathy and radiculopathy) or other leg-related movement disorders. Negative results from tests may indicate that the diagnosis is Restless Leg Syndrome. In some cases, sleep studies such as polysomnography (a test that records the patient's brain waves, heartbeat, and breathing during an entire night) are undertaken to identify the presence of PLMD.
The diagnosis is especially difficult with children because the physician relies heavily on the patient's explanations of symptoms, which, given the nature of the symptoms of Restless Leg Syndrome, can be difficult for a child to describe. The syndrome can sometimes be misdiagnosed as "growing pains" or attention deficit disorder.
How is Restless Legs Syndrome treated?
There is no cure for Restless Legs Syndrome, but there are a variety of lifestyle changes and medications that can help offer relief of RLS symptoms.
Certain lifestyle changes and activities may help to reduce or eliminate symptoms. Decreased use of caffeine, alcohol, and tobacco may provide some relief. Physicians may suggest that certain individuals take supplements to correct deficiencies in iron, folate, and magnesium.
Studies also have shown that maintaining a regular sleep pattern can reduce symptoms. Some individuals, finding that Restless Leg Syndrome symptoms are minimized in the early morning, change their sleep patterns.
Others have found that a program of regular moderate exercise helps them sleep better; on the other hand, excessive exercise has been reported by some patients to aggravate Restless Leg Syndrome symptoms. Taking a hot bath, massaging the legs, or using a heating pad or ice pack can help relieve symptoms in some patients. Although many patients find some relief with such measures, rarely do these efforts completely eliminate symptoms.
A variety of medications have been shown to help relieve symptoms.
Medications that raise dopamine levels, such as levodopa, have been shown to reduce Restless Leg Syndrome symptoms and PLMD and are considered the initial treatment of choice. These so-called dopaminergic agents are prescribed most commonly to treat Parkinson's disease, but are increasingly used to treat RLS.
Good short-term results of treatment with levodopa plus carbidopa have been reported, although most patients eventually will develop augmentation, meaning that symptoms are reduced at night but begin to develop earlier in the day than usual.
Dopamine agonists such as pramipexole (Mirapex®), and ropinirole (Requip®) may be effective in some patients and are less likely to cause augmentation.
Benzodiazepines, such as clonazepam (Klonopin®) and diazepam (Valium®), may be prescribed for patients who have mild or intermittent symptoms. These drugs help patients obtain a more restful sleep but they do not fully alleviate Restless Leg Syndrome symptoms and can cause daytime sleepiness. Because these depressants also may induce or aggravate sleep apnea in some cases, they should not be used in people with this condition.
Anticonvulsants, such as carbamazepine, are also useful for some people with RLS, as they decrease the sensory disturbances (creeping and crawling sensations). Dizziness, fatigue, and sleepiness are among the possible side effects.
Unfortunately, no one drug is effective for everyone with Restless Leg Syndrome. What may be helpful to one individual may actually worsen symptoms for another. In addition, medications taken regularly may lose their effect, making it necessary to change medications periodically.
What is the prognosis of people with Restless Legs Syndrome?
Restless Leg Syndrome is generally a lifelong condition for which there is no cure.
Symptoms may gradually worsen with age, though more slowly for those with the idiopathic form of Restless Leg Syndrome than for patients who also suffer from an associated medical condition.
Nevertheless, current therapies can control the disorder, minimizing symptoms and increasing periods of restful sleep. In addition, some patients have remissions, periods in which symptoms decrease or disappear for days, weeks, or months, although symptoms usually eventually reappear. A diagnosis of Restless Leg Syndrome does not indicate the onset of another neurological disease.
Reference: National Institute of Neurological Disorders and Stroke (NINDS)