Periodic Limb Movement Disorder

November 12, 2012

Periodic Limb Movement Disorder

Repetitive movement and cramping of the legs, especially during sleep is known as periodic limb movement disorder (PLMD). The movements are often rhythmic and occur every 20 to 40 seconds to disrupt sleep.

Causes

Limb movement disorder is often associated with restless legs syndrome. In fact, most people with restless legs syndrome also have PLMD, although the opposite is not always true. The disease can occur at any age but is common in middle-aged and older people.

Damage or abnormalities associated with nerves of the limbs can lead to primary PLMD. However, more research is required to identify the nature and form of these abnormalities. Secondary PLMD is caused by underlying conditions such as diabetes, iron deficiency, spinal cord injury, anemia and sleep apnea. Certain medications such as antidepressants, antidopaminergic agents and sedative medications can also lead to PLMD.

Symptoms

The most people with limb movement disorders experience poor sleep at night and look to make up for it during the daytime. They are, in fact, unaware of their limb movements until their partner informs them. The movements may involve one or both legs, and may involve knee, ankle and toes. They may occur every 20 to 40 seconds and last for about 2 seconds. They may range from mild jerks to kicking and thrashing.

Diagnosis

Most patients with limb movement disorders complain of drowsiness during the day and sleepless at night. You doctor would perform a thorough physical examination and analyze your habits and health history. Although there are no laboratory tests to confirm the diagnosis of PLMD, your doctor may order tests to diagnose underlying conditions such as diabetes or anemia. A sleep test known as polysomnography is the only way to confirm the diagnosis of limb movement disorder. Your doctor may also refer you to a neurologist, who will test for the presence of neurological problems in your limbs.

Treatment

There is no cure for limb movement disorder; however, treatment can help relieve the symptoms. Your doctor may prescribe medications to improve sleep and reduce the movement of the legs.

  • Benzodiazepines such as Clonazepam suppress contraction of muscles and sedate you. It is one of the most widely used drugs to treat limb movement disorder, and is known to reduce the number of limb movements per hour.

  • Dopaminergic agents such as levodopa/varbidopa combination can lower the levels of neurotransmitter dopamine, which regulates the movements of muscles.

  • Anticonvulsant agents including gabapentin can reduce the muscle contractions associated with PLMD.

  • GABA agonists promote relaxation of muscles by suppressing the action of neurotransmitters.

Prognosis

Most patients with limb movement disorders see an improvement in their symptoms with treatment.

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