Periodic Limb Movement Disorder (PLMD)
Basics
Description
Sleep-related movement disorder characterized by periodic limb movements of sleep (PLMS) with significant sleep disturbance and/or daytime functional impairment:
- PLMS demonstrated during polysomnography
- PLMS are repetitive contractions of 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 are 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, and somnolence.
- Bed partner may complain of patient’s movements.
- Other sleep disorders such as obstructive sleep apnea (OSA), narcolepsy, and restless legs syndrome (RLS) do not explain the PLMS.
- No associated restlessness or dysesthesia while awake
- If there is an associated sensory perception or restlessness, the diagnosis is not PLMD but possibly 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 (1).
- PLMS occurs in > 15% of insomnia patients.
- PLMS are frequent in narcolepsy, RBD, OSA, and during initiation of CPAP.
Prevalence
Etiology and Pathophysiology
- Understudied; most data reports on PLMS as it pertains to RLS:
- 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
- Spinal cord injury
- Pregnancy
- Medication side effects:
- Most antidepressants (except bupropion or desipramine) and lithium
- Some antipsychotic and antidementia medications
- Antiemetics (antidopaminergic)
- 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
- History of prematurity
General Prevention
- Promoting adequate sleep
- Avoid PLMS triggers such as iron deficiency, frequently observed in children (3).
Commonly Associated Conditions
- Narcolepsy
- End-stage renal disease; cardiovascular disease; stroke
- Gastric surgery
- Pregnancy
- Arthritis
- Lumbar spine disease; spinal cord injury
- Peripheral neuropathy
- Insomnia, insufficient sleep, parasomnias
- ADHD, anxiety, oppositional behaviors
Pediatric Considerations
- PLMD may precede overt RLS by years (3).
- Association with RLS is more common.
- Association and differential diagnosis with restless sleep disorder, ADHD, oppositional behaviors, mood disorders, growing pains (3)
Pregnancy Considerations
- May be secondary to iron, folate deficiency
- Most severe in the 3rd trimester
- Usually resolves after delivery
Geriatric Considerations
- May cause or exacerbate circadian disruption and “sundowning”
- PLMS may increase risk of atrial fibrillation in elderly.
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Citation
Domino, Frank J., et al., editors. "Periodic Limb Movement Disorder (PLMD)." 5-Minute Clinical Consult, 33rd ed., Wolters Kluwer, 2025. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117564/all/Periodic_Limb_Movement_Disorder__PLMD_.
Periodic Limb Movement Disorder (PLMD). In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2025. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117564/all/Periodic_Limb_Movement_Disorder__PLMD_. Accessed November 6, 2024.
Periodic Limb Movement Disorder (PLMD). (2025). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (33rd ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117564/all/Periodic_Limb_Movement_Disorder__PLMD_
Periodic Limb Movement Disorder (PLMD) [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2025. [cited 2024 November 06]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117564/all/Periodic_Limb_Movement_Disorder__PLMD_.
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