Restless leg syndrome and periodic limb movement disorder

Tuesday, June 28, 2005
Woman in bed asleep
What is restless leg syndrome?
RLS is a sleep disorder characterised by voluntary leg movements in response to uncomfortable "tingling" sensations in one or both legs. The sensations occur predominantly in the calf area, however, sensations from the thigh to the ankle are not uncommon. In rare cases, the symptoms occur in the arms.

As RLS follows a set daily cycle, the symptoms are felt more strongly at night, making it harder for sufferers to relax and fall asleep. Feelings of grogginess and tiredness the next day is not the only daytime problem experienced. RLS is also known to worsen when the sufferer is relaxed, or required to sit still for lengthy periods. This can often interfere with the length of time a sufferer, for instance, can travel by car, or sit still at a business meeting. The accumulation of sleep loss coupled with the disturbance of everyday activities, can lead to anxiety and depression.

What is periodic limb movement disorder (PLMD)?
Like RLS, PLMD is another sleep disorder that affects the limbs as well as a sufferer's ability to get a good night's sleep. While RLS movements are a voluntary response to unpleasant sensations in the limbs whilst awake, the movements of PLMD are involuntary and felt most when the sufferer is asleep. PLMD may accompany obstructive sleep apnoea, narcolepsy and insomnia, and is quite common in people with RLS.

As implied by its name, the limb movements occur at regular intervals of between 20 to 30 seconds apart, five times or more an hour during non-REM sleep. The movements are similar to jerking or kicking, and consist of a partial flexing of the big toe, ankle, knee and occasionally, the hips. Occurrences are not continuous throughout the night, but occasion more in clusters, in the first half of the night.

PLMD sufferers are generally unaware of their limb movements or the resultant "microarousals" (very brief awakenings) that lead to excessive daytime sleepiness the morning after. However, they do often complain of difficulty falling asleep, staying asleep or remaining alert and awake during the day. Other common symptoms include hot or cold feet, or hair wearing off the legs.

Bed partners are affected too. Many complain of being kicked during the night, fighting for bedcovers, or the bed shaking due to continuous leg movements.

What causes RLS?

  • Family history — Approximately 30 percent of RLS cases are hereditary related. Passed through the genes of either the father or mother, the symptoms tend to be more severe and more difficult to treat.
  • Pregnancy — RLS can develop during pregnancy, especially in the last six months. After delivery, the symptoms usually disappear.
  • Low iron levels or anaemia — people with these conditions are more likely to develop RLS. Once the iron level or anemia is corrected, the symptoms generally improve.
  • Chronic diseases — sufferers of kidney failure, diabetes, rheumatoid arthritis and peripheral neuropathy are more prone to developing RLS.
  • Caffeine and alcohol — decreasing caffeine and alcohol consumption may reduce symptoms.

What causes PLMD?
The same as above. However, PLMD is more common in people with kidney disease or narcolepsy. Antidepressant medication may also worsen the symptoms of PLMD.

How are these disorders diagnosed?

  • RLS
    At present, no laboratory test exists to detect RLS. Diagnosis can instead be made by reviewing your medical history. Having ruled out other medical conditions, your healthcare provider can ascertain whether RLS is the primary cause of your sensations. Words often used to describe RLS include "creepy", "crawly", "pulling" and "gnawing". With these symptoms comes an almost irresistible urge to move the affected limb.
  • PLMD
    As sufferers of PLMD are unaware of their limb movements whilst asleep, it is necessary to have a sleep study. By placing electrodes over the calf muscle of each leg, a determination of whether PLMD is present can be made.

Are these disorders treatable?
RLS is treatable with either of the following:

  • Home remedies — helpful in mild cases. These include having a hot bath, leg massage, applying heat or ice packs, aspirin or similar pain relievers, regular exercise and reducing caffeine. Taking Vitamin E and supplemental calcium can often be effective also.
  • Prescription drugs — for more severe cases, prescription medicine may be necessary. However, no one drug is a "cure all" as each person responds differently dependant upon the severity of the symptoms, other medical conditions, and other medications being used. Furthermore, continued usage of a particular medication can sometimes lead to a reduction in its effectiveness over time. Thus it is crucial to alternate between different categories of medication in order to control RLS.

Categories of commonly used RLS medication

  • Benzodiazepines — these are central nervous system depressants suppress RLS symptoms enough to enable a patient to fall sleep. Daytime drowsiness can often be a side effect of taking these medications. Sleep apnoea sufferers should avoid these type when possible.
  • Dopaminergic agents — used in the treatment of Parkinson's disease, and also effective in reducing symptoms of RLS and PLMS
  • Opioids — these are pain killers that are useful for severe cases, where unrelenting symptoms are experienced.

Most PLMD sufferers require no treatment as they are not sleepy during the day or suffer insomnia by night. For those whose sleep is disrupted, the best treatment is to improve one's sleep hygiene.

Be a good sleeper

  • Keep a regular sleep schedule — that means going to bed and waking up at the same time every day, including at weekends!
  • Get enough sleep every night — determine how much sleep your body needs to be fully alert and awake all day and make sure you get it! Research shows that people require at least 60 to 90 minutes more sleep than they are presently getting.
  • Go to bed only when sleepy — if you're not tired, leave the bedroom and do something else. Restricting your time in bed to just what you need, will enable you to have a deeper and continuous sleep.
  • Repay your sleep debt — make up for any lost sleep as soon as possible.
  • Exercise regularly — exercise can reduce stress, anxiety and insomnia, provided it is conducted at least six hours before bedtime.

©2003 Sleep & Chest Disorders Centre

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