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When patients are being evaluated for sleep problems we ask if they have “creepy crawly” feelings in the legs with a strong urge to move them that make it difficult to fall asleep. Many patients report these symptoms and they can significantly impact the quantity of sleep that patients get. While these restless legs symptoms may be associated with insomnia, these are distinct from the problems of over-arousal and worry that are a part of insomnia. The severity of symptoms may vary from patient to patient and an individual patient’s symptoms may over time as well. Symptoms can come and go and there may be long periods of remission. Why this is the case is currently unknown.
Restless legs symptoms were reported for centuries but it was only in the 1940s that it was determined to be a neurological disorder by Swedish physician, Carl Ekbom. The disorder is usually called Restless Legs Syndrome (RLS), it is sometimes also referred to as Willis-Ekbom disease. RLS is a sensorimotor disorder and is thought to affect between 5% to 10% of the population of North America with as many as 2% to 3% being affected to a clinically significant degree. Although there is no difference in boys and girls, women are more often affected than men and the disorder may be worsened by pregnancy. We usually think of the legs as being the primary area affected by this disorder but it can also be experienced in the arms. Indeed, as many as 50% of patients with this diagnosis also report symptoms in the arms. Cruelly, these symptoms have a circadian pattern to them and start or get worse late in the day around the time that patients are preparing to go to sleep. Disturbed sleep affects 60% - 90% of patients with RLS. Difficulty falling asleep due to an urge to move the legs is the most common reason for people to seek treatment. Often, however, the diagnosis is made on the basis of information gathered during a sleep evaluation for another sleep disorder.
The main features of RLS are an urge to move the legs (or arms) along with unpleasant sensations in the limbs that start or get worse during times of rest. Movements such as stretching or walking temporarily relieve these sensations. The symptoms are not accounted for by other conditions such as leg cramps or pain from arthritis, and are intense enough to cause distress, disrupt sleep and impair functioning. People with RLS often report daytime sleepiness and fatigue, but these symptoms are usually less than would be expected from the reported degree of sleep disruption. This suggests that, as with insomnia, there is some degree of over-arousal involved with the condition. It can start at any age from childhood to late in life with increasing prevalence with age.
Primary causal factors associated with RLS are iron deficiency, problems with dopamine regulation in the central nervous system, and genetic factors. RLS, especially if it starts early in life, most likely has some genetic basis and tends to run in families. Symptoms may be precipitated by iron deficiency (most often seen in young women) or by use of certain medications such as sedating antihistamines and most antidepressants. A number of medical conditions such as renal disease, diabetes and Parkinson’s disease can cause RLS-like symptoms. RLS appears to involve the dopamine system but does not predict the onset of Parkinson’s disease. The circadian pattern of this disorder may be related to rising levels of melatonin. Melatonin levels rise in the evening leading to the onset of drowsiness. People with RLS may have increased levels of hypocretin, a neurotransmitter that is involved in arousal. Increased hypocretin may counteract some of the sleepiness that would otherwise be expected because of sleep disruption.
RLS is a clinical diagnosis based on patient report. Nocturnal polysomnography, used to diagnose sleep apnea, has limited utility in the diagnosis of RLS. During sleep testing, patients complaining of RLS symptoms often show a long latency to achieve persistent sleep and have more frequent arousals. Efforts have been made to develop more objective measures of RLS. For example, the Immobilization Test is conducted in the evening before the usual bedtime. Patients get into bed while reclined at a 45-degree angle. Eyes are kept open and the legs are kept outstretched. Instructions are given to avoid movement for the duration of the test that lasts one hour. Muscle electrical activity sensors are used to measure leg movements. During the test the patient is asked to rate the degree of discomfort being experienced. The discomfort ratings have shown some evidence of being able to distinguish RLS patients from control participants. This test is not currently in use for clinical evaluation and patient report is the most important source of information for the sleep evaluation.
RLS is associated with several other behavioral and sleep disorders. Anxiety and depression are more common in patients with RLS than in the general population. About one in four patients with RLS also have attention deficit hyperactivity disorder and between 12% and 35% of patients with ADHD have RLS. Periodic Limb Movement Disorder (PLMD) is another sleep-related movement disorder, and unlike RLS, it can be detected on a sleep study. In PLMD there are repeated leg kicks that occur during sleep. For patients with PLMD there is no increased risk for RLS, but about 70% - 80% of patients with RLS also have periodic limb movements.
Several medical treatments are available for RLS. Patients with low iron levels can take iron supplements. (Iron supplementation should only be undertaken after discussion with your physician. Blood testing will be needed to determine if low iron levels are actually present in patients with RLS.) If low iron is not an issue, then several pharmacological treatments can be used when indicated. Levodopa has been show to have beneficial effects on RLS, but it may have a number of adverse effects including the onset of RLS symptoms in the morning and symptoms occurring earlier in the day than before taking it. The dopamine agonists, pramipexole and ropinirole, are most often used as they have fewer adverse effects than Levodopa and are the primary treatment for RLS. In severe cases of RLS opioids such as Oxydodone and Codeine have been used. Opioids, however, need to be used carefully as they are not appropriate for people with a previous history of substance abuse, and can increase breathing difficulties in people who snore or have sleep apnea. Gabapentin, an anticonvulsant medication, is helpful in patients with mild symptoms or who have developed adverse effects with the dopamine agonists. Benzodiazepines such as clonazepam and temazepam have been used either alone to help improve continuity of sleep, or as an adjunct to the dopamine agonists. (Dopamine agonists can cause some arousal that may have an adverse affect on sleep.)
Behaviorally there are a number of strategies that can be used to alleviate RLS symptoms. One that can be helpful but is often not practical or possible for patients is to take jobs that allow for working during the time when the disorder is most likely to occur, such as second or third shift. Non-pharmacological interventions include avoiding nicotine, caffeine and alcohol near bedtime. Engaging in regular exercise of the legs and taking a hot bath in the hour before bedtime may give some relief. Stretching at bedtime may help, but this help typically lasts for just a few moments. It also is important for patients to focus on good sleep hygiene as it is not uncommon for patients with RLS to develop additional symptoms of insomnia due to the worry and concern about not being able to fall asleep.
If you are troubled by restless legs symptoms to the degree that they are significantly interfering with your sleep or are leading to poor daytime functioning, it IS possible to get help. You can try the non-pharmacological interventions described above. If these are ineffective, describe the symptoms to your primary care physician. Medication may be helpful and can reduce the suffering and dysfunction caused by RLS. There is no need for this to be yet another cause of being sleepless in America…
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