Pediatric Sleep Disorders/Sleep in Children with Chronic Illness.

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WHAT IS PERIODIC LIMB MOVEMENT DISORDER?

Periodic limb movement disorder (PLMD) is a neurological disorder that occurs during sleep. It involves episodes of repetitive movements, usually in the legs. They occur approximately every 20 to 40 seconds. The movements may appear as brief muscle twitches, jerking movements, leg kicks, or an upward flexing of the feet. These movements occur in clusters, lasting from a few minutes to a few hours. Most children and adolescents with PLMD are not aware of the move- ments. However, PLMD can result in frequent brief arousals throughout the night, leading to daytime sleepiness.

Children and adolescents with PLMD also often have restless legs syndrome (RLS). RLS is a related disorder and involves an urge to move the legs, which is typically worse at bedtime and sometimes when sitting still for a long time. It is accompanied by uncomfortable sensations in the legs (tingling, burning, “creepy-crawly”), which are relieved by movement. Children with RLS often have difficulty falling asleep at bedtime.

WHAT CAUSES PERIODIC LIMB MOVEMENTS?

Periodic limb movements may run in families. PLMD is often related to low iron (with or without anemia). In addition, some children with a chronic illness, such as diabetes, cancer, and kidney disease, are at increased risk for developing PLMD.

WHAT ARE THE SYMPTOMS OF PERIODIC LIMB MOVEMENT DISORDER?

The symptoms of PLMD may include any of the following, although many children and adoles- cents do not report any symptoms.

n Leg movements: Repetitive leg movements in sleep characterize PLMD. The child or adoles- cent is usually not aware of these movements, but leg movements may be seen by parents.

n Restless sleep and sleep disruption: Children and adolescents with PLMD are often de- scribed as restless sleepers. This is because of the leg movements and frequent arousals. Some children also wake up multiple times at night. Children with both RLS and PLMD often have difficulty falling asleep as well.

n Daytime sleepiness: The sleep disruption associated with PLMD can result in being sleepy the next day. In addition, problems with mood, behavior, and school are common in children with PLMD. They may also be hyperactive, impulsive, irritable, and have poor concentration.

HOW IS PERIODIC LIMB MOVEMENT DISORDER DIAGNOSED?

An overnight sleep study is required to confirm the diagnosis of PLMD. In addition, a medical history and physical examination will be conducted. Your child’s doctor may order a blood test, called a “serum ferritin level,” for low iron.

Periodic Limb Movement Disorder

© Mindell JA & Owens JA (2010). A Clinical Guide to Pediatric Sleep: Diagnosis and Management of Sleep Problems, 2nd ed. Philadelphia: Lippincott Williams & Wilkins

2 PerioDic LiMb MoveMent DisorDer

© Mindell JA & Owens JA (2010). A Clinical Guide to Pediatric Sleep: Diagnosis and Management of Sleep Problems, 2nd ed. Philadelphia: Lippincott Williams & Wilkins

HOW IS PERIODIC LIMB MOVEMENT DISORDER TREATED?

Treatment for PLMD may involve any of the following.

n Good sleep hygiene: It is especially important that children and adolescents with PLMD maintain good sleep hygiene. This includes getting enough sleep and keeping a regular sleep schedule.

n Treat RLS: If restless legs symptoms are also present, treatment of the RLS may improve sleep.

n Avoid caffeine: Caffeine can make PLMD symptoms worse. Caffeine can be found in many sodas, tea, and coffee, as well as some medicines such as Excedrin.

n Treat iron deficiency: If a blood test shows low iron (ferritin level <50), then iron supple- ments are usually recommended. The amount of iron in these supplements is typically more than that in a regular multivitamin, and several months of treatment are often needed to in- crease the ferritin level. Your doctor may recommend an iron supplement that also includes vitamin C. Vitamin C will increase the iron absorption. Some children develop constipation with iron supplements. Pay attention to your child’s diet, including increasing high fiber foods and increasing fluids. The addition of a stool softener is occasionally needed.

n Consider medication: For children and adolescents with PLMD whose sleep is very dis- rupted, medication may be recommended. There are a number of different types of medica- tions that can help. Your doctor can discuss these with you.