What is Restless Legs Syndrome and how do I treat it?

Restless Legs Syndrome (RLS), which often appears in otherwise healthy people, is not related to emotional or mental problems. As the name suggests, the symptoms mostly affect the legs, but the arms and (rarely) trunk may also be involved.

People experience restless legs in many different ways, but most describe very unpleasant sensations that occur in the legs (most often the calves) when they are sitting or lying still, especially in the evening or at bedtime. If you have RLS you know it is not like the pain of a leg cramp, but you may have difficulty describing the exact feeling. However, virtually everyone with this disorder reports that the uncomfortable feelings are temporarily relieved by stretching or moving the legs.

These sensations are often disturbing enough to cause insomnia. The constant need to stretch or move the legs to get rid of the discomfort often prevents a person with RLS from falling asleep. As a result, these individuals may be extremely tired during the day and unable to perform well at work or take part in social activities. Restless legs syndrome also occurs in children, where it can affect their schoolwork and may cause symptoms that are confused with attention deficit/hyperactivity disorder (ADHD).

The sleepiness that results from a restless night is not the only daytime problem you might experience if you have RLS. During the day, RLS can interfere with the length of time you can travel by car, airplane, or any other kind of transportation. requiring you to sit still for long periods of time. Restless legs syndrome may disturb your ability to sit still at movies, concerts, and in business meetings. The sleep loss along with the disturbance of daytime activities can lead to anxiety and depression.

What is Periodic Limb Movement Disorder?

Periodic limb movement disorder (PLMD), also known as nocturnal myoclonus, is related to RLS but is exhibited during sleep rather than while awake. Periodic limb movements usually occur in the legs but may also  affect the arms, and are involuntary (that is, not consciously controlled). They typically consist of an extension of the big toe together with an upward bending of the ankle, sometimes with flexing of the knee and/or hip. An observer miight describe them as a "jerk" or "kick". As the name implies, the movements occur at periodic (regular) intervals wit 20 - 40 seconds separating each kick, and a series of at least 4 jerks must be seen in order to diagnose PLMD (frequently many more than 4 kicks are seen in a row). The movements usually do not occur continously throughout sleep, but instead cluster in the first half of the night. Since a certain number of periodic limb movements occur in normal sleeping individuals, PLMD is only diagnosed when 5 or more occur per hour of sleep, average over the entire night.

Periodic limb movements are different from the "hypnic jerk", a sudden movement of the entire body usually accompanied by the sensation of falling that takes place soon after sleep begins. Hypnic jerks are quite normal and usually do not interfere with sleep quality or cause daytime symptoms.

People with PLMD are often not aware of these movements, although some may notice similar involuntary movements while they are still awake. Research studies of RLS have suggested that awake PLMD is similar to, or may be the same as, RLS. Most people with RLS have periodic limb movements during sleep, but patients who show PLMD only while asleep often do not have RLS.

Individuals with PLMD may be awakened by leg movements occurring immediately after falling asleep, and awaken so quickly that they may not realize that they were asleep. These patients may complain of difficulty falling asleep. Other patients may report difficulty staying asleep, and may in fact be experiencing leg movements throughout the night that are accompanied by "microarousals" (very brief awakenings) that create an overall feeling of a poor night's sleep or sleeping very little. Other individuals with PLMD may have only a general complaint of restless or poor sleep.

How Common are RLS & PLMD?

Restless Legs Syndrome - Five to 15 of every 100 people experience the discomfort of RLS at some time in their lives. The disorder is more common in older individuals but can occur at any age in both men and women. Several recent reports have shown that RLS is not uncommon in children, and that so-called "growing pains" may actually be symptons of RLS. Restless legs can also be severe during pregnancy, especially during the last isx months. Over the course of years, RLS may come and go without any obvious cause.

Periocic Limb Movement Disorder

PLMD is rare in people under 30 years of age, but becomes more common as people grow older. PLMD affects a small percentage of people age 30 to 50; one-third of people age 50 to 65; and almost half of people over age 65. Men and women are equally likely to be affected. PLMD contributes to the inability to sleep in two out of every ten people who have been diagnosed with insomnia.

What causes these disorders?

Although we don't know the actual cause of RLS or PLMD, these are some related conditions and hereditary signs to consider.

Restless Legs Syndrome - In about 30 cases out of 100, RLS is an inherited disorder, and a parent, grandparent, aunt or uncle can be identified who also has symptoms of RLS. For the same reason, siblings or children of the individual with RLS are more likely to have symptoms. The causes of the other 70% of RLS cases are not clearly known. The cases of RLS that rum in families often have more severe symptoms and are sometimes more difficult to treat.

A number of situations seem to be related to, or produce the symptoms of RLS. These situations include: iron deficiency anemia, poor blood circulation in the legs, disorders involving the nerves in the limbs or spinal cord, kidney disorders, alcoholism, and certain vitamin or mineral deficiencies. Other things that may trigger RLS are stopping or starting certain medications, caffeine, tobacco, fatigue, hot temperatures, or extended time in cold temperatures.

Periodic Limb Movement Disorder

The same factors that are associated with RLS are also associated with PLMD. Also, PLMD is more common in patients with a sleep disorder called narcolepsy.