Periodic Limb Movement Disorder (PLMD)
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Basics
Description
Sleep-related movement disorder characterized by periodic limb movements of sleep (PLMS) with significant sleep disturbance and/or daytime functional impairment:
- Periodic limb movements of sleep (PLMS) demonstrated during polysomnography
- PLMS are repetitive contractions of the tibialis anterior muscles occurring mainly in non-rapid eye movement (NREM) sleep.
- Movements consist of unilateral or bilateral, simultaneous or not, rhythmical extension of the big toe and ankle dorsiflexion.
- Sometimes, knee and hip flexion is noted.
- Arm movements or more generalized movements occur less commonly.
- Movements might be associated with cortical arousals from sleep unbeknownst to the patient (PLMs with arousals—PLMA).
- A clinical history of significant sleep disturbance and/or functional impairment is necessary for diagnosis
- Complaints include insomnia, nonrestorative sleep, daytime fatigue, somnolence.
- Bed partner may complain of patient’s movements.
- Other sleep disorders such as obstructive sleep apnea (OSA), narcolepsy, restless legs syndrome do not explain the PLMS (1)[A].
- No associated restlessness or dysesthesia while awake
- If there is an associated sensory perception or restlessness, the diagnosis is not PLMD but possibly restless leg syndrome (RLS).
- System(s) affected: musculoskeletal, nervous
- Synonym(s) referring to the PLMS: nocturnal myoclonus; sleep myoclonus
Epidemiology
Incidence- PLMD is rare, affecting children and adults (2).
- PLMS occurs in >15% of insomnia patients.
- PLMS are frequent in rapid eye movement (REM) sleep behavior disorder (RBD) occurring during REM sleep.
- PLMS are frequent in narcolepsy, in OSA, and during initiation of continuous positive airway pressure.
Prevalence
Etiology and Pathophysiology
- Understudied; most data reports on PLMS as it pertains to RLS:
- Brain iron deficiency causing central nervous system (CNS) dopamine dysregulation
- Suprasegmental disinhibition at the brainstem and spinal cord levels
- Spinal cord excitability
- CNS dopamine dysregulation supported by increased incidence of PLMS in untreated Parkinson disease (PD) and decreased incidence of PLMS in schizophrenia.
- Triggering and exacerbating factors:
- Peripheral neuropathy
- Arthritis
- Renal failure
- Synucleinopathies (multiple-system atrophy)
- Spinal cord injury
- Pregnancy
- Medications
- Most antidepressants (except bupropion or desipramine) and lithium
- Some antipsychotic and antidementia medications
- Antiemetics (metoclopramide)
- Sedating antihistamines
Genetics
BTBD9 on chromosome 6p associated with PLMS in patients with or without RLS but not in RLS patients without PLMS
Risk Factors
- Family history of RLS
- Iron deficiency and associated conditions
- Peripheral neuropathy
- Arthritis, orthopedic problems
- Chronic limb pain or discomfort
General Prevention
- Promoting adequate sleep
- Avoid PLMS triggers such as iron deficiency, frequently observed in children (4).
- Awareness, including family history
Commonly Associated Conditions
- Narcolepsy
- Iron deficiency
- End-stage renal disease (ESRD)
- Cardiovascular disease; stroke
- Gastric surgery
- Pregnancy
- Arthritis
- Synucleinopathies-multiple-system atrophy
- Lumbar spine disease; spinal cord injury
- Peripheral neuropathy
- Insomnia, insufficient sleep, parasomnias
- Attention deficit hyperactivity disorder (ADHD)
- Mood disorder, anxiety, oppositional behaviors
Pediatric Considerations
- PLMD may precede overt RLS by years (4).
- Association with RLS is more common.
- Symptoms may be more resultant than in adults (5)[B].
- Association and differential diagnosis with ADHD, oppositional behaviors, mood disorders, growing pains (4)
Pregnancy Considerations
PLMD is not well studied in pregnant women; implying from literature on RLS with PLMS in pregnant women:
- May be secondary to iron, folate deficiency
- Most severe in the 3rd trimester
- Usually resolves after delivery
Geriatric Considerations
- Potential source of sleep disturbance
- May cause or exacerbate circadian disruption and “sundowning”
- Medications that may trigger or exacerbate PLMs, which can lead to PLMD or RLS.
- There is a growing literature suggesting an increase risk of atrial fibrillation with PLMS.
-- To view the remaining sections of this topic, please log in or purchase a subscription --
Basics
Description
Sleep-related movement disorder characterized by periodic limb movements of sleep (PLMS) with significant sleep disturbance and/or daytime functional impairment:
- Periodic limb movements of sleep (PLMS) demonstrated during polysomnography
- PLMS are repetitive contractions of the tibialis anterior muscles occurring mainly in non-rapid eye movement (NREM) sleep.
- Movements consist of unilateral or bilateral, simultaneous or not, rhythmical extension of the big toe and ankle dorsiflexion.
- Sometimes, knee and hip flexion is noted.
- Arm movements or more generalized movements occur less commonly.
- Movements might be associated with cortical arousals from sleep unbeknownst to the patient (PLMs with arousals—PLMA).
- A clinical history of significant sleep disturbance and/or functional impairment is necessary for diagnosis
- Complaints include insomnia, nonrestorative sleep, daytime fatigue, somnolence.
- Bed partner may complain of patient’s movements.
- Other sleep disorders such as obstructive sleep apnea (OSA), narcolepsy, restless legs syndrome do not explain the PLMS (1)[A].
- No associated restlessness or dysesthesia while awake
- If there is an associated sensory perception or restlessness, the diagnosis is not PLMD but possibly restless leg syndrome (RLS).
- System(s) affected: musculoskeletal, nervous
- Synonym(s) referring to the PLMS: nocturnal myoclonus; sleep myoclonus
Epidemiology
Incidence- PLMD is rare, affecting children and adults (2).
- PLMS occurs in >15% of insomnia patients.
- PLMS are frequent in rapid eye movement (REM) sleep behavior disorder (RBD) occurring during REM sleep.
- PLMS are frequent in narcolepsy, in OSA, and during initiation of continuous positive airway pressure.
Prevalence
Etiology and Pathophysiology
- Understudied; most data reports on PLMS as it pertains to RLS:
- Brain iron deficiency causing central nervous system (CNS) dopamine dysregulation
- Suprasegmental disinhibition at the brainstem and spinal cord levels
- Spinal cord excitability
- CNS dopamine dysregulation supported by increased incidence of PLMS in untreated Parkinson disease (PD) and decreased incidence of PLMS in schizophrenia.
- Triggering and exacerbating factors:
- Peripheral neuropathy
- Arthritis
- Renal failure
- Synucleinopathies (multiple-system atrophy)
- Spinal cord injury
- Pregnancy
- Medications
- Most antidepressants (except bupropion or desipramine) and lithium
- Some antipsychotic and antidementia medications
- Antiemetics (metoclopramide)
- Sedating antihistamines
Genetics
BTBD9 on chromosome 6p associated with PLMS in patients with or without RLS but not in RLS patients without PLMS
Risk Factors
- Family history of RLS
- Iron deficiency and associated conditions
- Peripheral neuropathy
- Arthritis, orthopedic problems
- Chronic limb pain or discomfort
General Prevention
- Promoting adequate sleep
- Avoid PLMS triggers such as iron deficiency, frequently observed in children (4).
- Awareness, including family history
Commonly Associated Conditions
- Narcolepsy
- Iron deficiency
- End-stage renal disease (ESRD)
- Cardiovascular disease; stroke
- Gastric surgery
- Pregnancy
- Arthritis
- Synucleinopathies-multiple-system atrophy
- Lumbar spine disease; spinal cord injury
- Peripheral neuropathy
- Insomnia, insufficient sleep, parasomnias
- Attention deficit hyperactivity disorder (ADHD)
- Mood disorder, anxiety, oppositional behaviors
Pediatric Considerations
- PLMD may precede overt RLS by years (4).
- Association with RLS is more common.
- Symptoms may be more resultant than in adults (5)[B].
- Association and differential diagnosis with ADHD, oppositional behaviors, mood disorders, growing pains (4)
Pregnancy Considerations
PLMD is not well studied in pregnant women; implying from literature on RLS with PLMS in pregnant women:
- May be secondary to iron, folate deficiency
- Most severe in the 3rd trimester
- Usually resolves after delivery
Geriatric Considerations
- Potential source of sleep disturbance
- May cause or exacerbate circadian disruption and “sundowning”
- Medications that may trigger or exacerbate PLMs, which can lead to PLMD or RLS.
- There is a growing literature suggesting an increase risk of atrial fibrillation with PLMS.
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