Restless legs syndrome (RLS) and periodic leg movements in sleep (PLMS) are relatively common conditions that usually affect older adults. RLS and PLMS commonly occur together and are generally treated in the same manner. They may be associated with underlying medical conditions, such as diabetes or kidney diseases. A number of different treatments are available which have been shown to be effective in both RLS and PLMS.
RLS is usually described as creeping sensations in the legs, accompanied by a strong desire to move the legs. These symptoms are worse at rest. They usually occur in the evening and may get worse as the evening progresses. As a result, patients with RLS may have difficulty falling asleep.
RLS affects approximately 5-15% of the population. This chronic movement disorder may begin at any age, but the symptoms typically become more pronounced in the above 40 age group. In fact, symptoms tend to become worse and more frequent as the sufferer grows older.
More females are affected than males, and females tend to report more symptoms as well. Although the name suggests a leg movement disorder, the restlessness and discomfort may spread to involve the arms in about 20-30% of more severely affected patients. One in five patients may report the abnormal sensations to be painful.
About 80% of patients with RLS also experience PLM in sleep.
PLMS consists of frequent rhythmic movements of the legs and feet during sleep. People with PLMS are often described as restless sleepers and they may feel tired during the day due to the sleep disruption caused by the leg movements in sleep. PLMS is easily diagnosed by an overnight stay in hospital for a sleep study.
PLMS is a term used to describe a series of complex, involuntary, repetitive and stereotypic upward movements involving upward motion of the big toe, downward and fanning motion of the other toes and accompanied by bending of the ankle, knees and thighs. PLMS is measured in the sleep laboratory using electrodes placed on the skin on the front of the legs (anterior tibialis muscles). Leg movements are scored as PLMS if occurring in a sequence of four or more movements lasting 0.5 to 5 seconds each episode and recurring every 20-40 seconds.
If you frequently experience the following symptoms, you may have RLS with or without accompanying PLMS.
If you do have RLS, you are not alone. Approximately five out of every 100 people will experience RLS at some point in their life.
No one knows the exact cause of these disorders as yet. However, research has indicated that people with RLS have problems with a brain chemical called dopamine and a decrease in the level of iron in an area of the brain that controls movements, called substantia nigra.
RLS can be a primary or secondary disorder. 'Primary RLS' is when no specific causes are found and 'Secondary RLS' is when certain conditions or medications cause RLS or worsen the symptoms.
RLS may run in families; more than 40% of patients have a family history of the disorder. There is ongoing research looking for genes that may be responsible for RLS.
Some of the more common factors that may cause secondary RLS are:
In most cases, RLS symptoms may decrease or disappear when the associated factors are treated or removed.
Your physician will go through your medical history and medication list in detail, examine you physically, and order a blood test.
The aim of all this is to:
This depends on the severity and frequency of the symptoms. In all patients, associated factors should be treated or removed where possible as this may decrease or abolish symptoms of RLS.
Medications are generally not required in mild cases. Simple remedies such as the following may be adequate:
In those with reduced iron stores, iron supplementation may be considered after exclusion of potential causes (e.g. bleeding, dietary deficiency, kidney failure). Concurrent supplementation with vitamin C to aid iron absorption may be helpful.
The most common medications for RLS and PLM are:
People with RLS may complain of varying degree of leg discomfort during the daytime. Some people may even experience problems with memory and concentration. However, many people are affected most significantly at bedtime as the symptoms are worse with inactivity and at night, and this makes it difficult to fall asleep. It is not uncommon for them to get up several times to walk around until symptoms are partially relieved.
On the other hand, PLMS occurs when the person is already asleep and can range in intensity from mild twitches to violent kicks. Although the peak of PLMS activity typically occurs in the early part of sleep, leg movements may be present for the entire night in more affected individuals. In the laboratory, PLMS is considered severe if it occurs 50 times or more per hour—especially if movement causes frequent brief awakenings (arousals) at least 25 times per hour. Generally, people with PLMS are not consciously aware of these awakenings, but if they occur very frequently, sleep may be severely disrupted resulting in excessive daytime sleepiness. PLMS may also result in the bed partner being kicked, sometimes violently, and wearing out of bedsheets on some occasions.
The answer is no, although the two conditions may interact.
A sleep study can therefore be of value in certain patients, if another cause of sleep disturbance such as OSA is suspected, and needs to be confirmed.
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