Restless Legs Syndrome
Restless Limbs Syndrome
Periodic Limb Movements Disorder
Restless Legs Syndrome (RLS): Restless legs syndrome is a disorder characterized by disagreeable leg sensations that usually start prior to sleep onset and that cause an irresistible urge to move the legs. The sensations are usually described as throbbing, aching, creeping, crawling, pulling, pricking, tingling and itching etc. The sensation generally affects the lower legs but may affect feet, thighs, arms, trunk and head. Some patients with RLS may have uncomfortable genital sensations and urgency to void (overactive bladder syndrome).
There is the partial or complete relief of the sensation with leg motion and the return of the symptoms upon cessation of the movements. The sensations and associated leg movements may interfere with sleep onset and may be present if the person wakes up during the night. The restless legs episodes are more likely to occur between 10 pm to 4 am.
As many as two third of patients have a family history of a similar condition. About 80-85% of RLS patients also experience periodic limb movements (see below). In addition, patients may have periodic and aperiodic limb movements while awake and at rest.
About 2% of children ages 8 to 17 have RLS. The majority of these children have a parent with RLS. The children with RLS may have attention deficit hyperactivity disorder type symptoms.
20% pregnant women report having RLS and it may be related to iron and vitamin deficiency. The condition usually goes away within four weeks after delivery. Women with postpartum depressive symptoms had higher prevalence of excessive daytime sleepiness and restless legs in last trimester of pregnancy,
Iron deficiency, even at a level too mild to cause anemia, has been linked to RLS in some people. This can be confirmed by doing a blood test called ferritin level. The ferritin should be maintained at value greater than 100 mcg/L.
The RLS may be seen in patients with obstructive sleep apnea and may not respond to treatment till the sleep apnea is adequately treated.
RLS may be seen more frequently in association with certain medical conditions such as chronic kidney disease (uremia), kidney dialysis, diabetes, magnesium deficiency, folate deficiency, hypothyroidism, varicose veins, osteoarthritis, rheumatoid arthritis, fibromyalgia, alcoholism, depression, attention deficit disorder, narcolepsy, Parkinson’s disease, multiple sclerosis, migraine with aura, brain injury, spinal cord injury, peripheral neuropathy and certain muscle conditions.
Certain medications including antidepressants, antipsychotics, certain blood pressure pills, metoclopramide, diuretics, asthma drugs, antihistamines and decongestants may cause RLS.
Good sleep hygiene, exercise, and avoidance of alcohol and caffeine may help. Heavy exercise in the evening may worsen RLS.
Treatment with medications is very helpful in most cases of RLS. The anti-Parkinson’s drugs that are commonly used for RLS may become counterproductive for about 6% people. They may develop augmentation of the condition with long term. The term augmentation means worsening of RLS and the restlessness may start to occur earlier in the evening or in the afternoons.
Periodic Limb Movements Disorder (PLMD): People with this condition have repeated movements in legs or arms during sleep. The typical movements are bending of big toe, ankle and knee. Sometimes, similar movements are seen in the arms. The movements occur every 5 to 90 seconds and last for 0.5 to 5.0 seconds.
The movements vary from barely noticeable to wild kicking and thrashing. The patient is ordinarily not aware of any movements but the bed partner’s sleep may get affected. The disorder is often totally asymptomatic. Some patients may have morning and daytime fatigue and sleepiness. They may anxiety and depression related to the chronic sleep disturbance. This disorder can be diagnosed in a sleep laboratory. About a third of the patients with periodic limb movements have restless legs.
The causes include sleep apnea, iron deficiency, diabetes mellitus, chronic kidney disease, narcolepsy, spinal cord injury, spinal cord tumor, medications and benzodiazepine withdrawal. They medications that worsen the periodic limb movements include antidepressants, antipsychotics, certain blood pressure pills, levodopa/carbidopa, metoclopramide, diuretics, antihistamines and decongestants
There is growing scientific evidence that the periodic limb movements contribute to high blood pressure and cardiovascular disease.
If it is felt necessary to treat the periodic limb movements, medications are helpful in most cases.