Restless Legs and Periodic Limb Movement Syndrome

What is it?

RLS involves an unpleasant, nervous or “antsy” sensation in the legs, relieved by walking, but prominent when inactive and trying to fall asleep.

Most patients with RLS also have “Periodic Limb Movement Syndrome (PLMS) “, but most patients with PLMS do not have RLS. Restless Legs symptoms occur in wakefulness, whereas Periodic Limb Movement Syndrome occurs primarily during sleep. Both are extremely common.

What causes it?

  • It can “run in families”.
  • RLS is often related to even borderline low body iron stores, and it is advisable to have your doctor check a special blood test (serum ferritin level). If the result is less than 50, oral iron may be very helpful.

IMPORTANT: One should not simply take iron without checking this level, since it is possible to overload the body with iron.

  • RLS sometimes is related to kidney failure, peripheral neuropathies (conduction abnormalities in the nerves of the legs) and other medical problems. It may worsen during pregnancies.
  • Even small amounts of caffeine can worsen RLS, and caffeine should be totally avoided.

How is it treated?

Treatment of RLS can be very difficult.

  • Some patients respond to gabapentin (Neurontin® or low dose opiates such as codeine.
  • Drugs that are usually given for Parkinson’s disease are typically extremely effective initially but in many cases, their use over time results in a phenomenon called augmentation (with worsening of the RLS symptoms to a degree worse than before treatment was begun: often with occurence of symptoms earlier in the day and with spread to the arms and upper body. Sinemet® (carbidopa/levodopa) is particularly likely to cause augmentation. The same problem sometimes occurs with other anti-Parkinson drugs such as Mirapex® and Requip®.
  • Some patients report improvement with marked restriction of salt in their diet.

Periodic Limb Movement Syndrome (PLMS)

What is it?

PLMS involves repeated upward jerking movements of the toes, ankle, or entire leg at nearly predictable (usually every 20-40 second) intervals in sleep. The movements are reminiscent of a Babinski reflex that occurs in infants.

What causes it?

  • PLMS becomes more common with increasing age.
  • The movements are often worsened by medications, particularly antidepressants.
  • People with PLMS may note repeated awakenings, daytime fatigue, or no symptoms at all: in which no treatment may be necessary.

What symptoms result from PLMS?

  • In many cases, no symptoms at all. It is a common incidental finding during sleep studies that are being performed for other reasons.
  • Bed partners may complain about being kicked repeatedly!
  • Some patients complain of repeated awakenings or fatigue. However, most patients with PLMS do not experience resulting sleepiness.

How is it treated?

  • If PLMS is not causing symptoms in a given patient, it is probably best left untreated.
  • Sometimes wearing elastic support hose, using a pillow between or under the legs, or taking a hot bath before retiring seems to help.
  • If medications are a factor, substitution of other drugs may be worth considering. It should be noted that in contrast to most of the other antidepressants, bupropion is not associated with worsening of PLMS.
  • Medications that have been helpful are the same as those listed above for RLS.
  • Another drug, clonazepam, sometimes helps. However, it may simply reduce arousals and awakenings that result from the leg jerks, without actually reducing the number of leg jerks that occur during the night.
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