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PLMD may precede overt RLS by years.
Association with RLS is more common than in adults.
Symptoms may be more consequential than in adults.
Associated with ADHD
Pregnancy Considerations
May be secondary to iron or folate deficiency
Most severe in 3rd trimester
Usually subsides after delivery
Geriatric Considerations
May become a significant source of sleep disturbance
May cause or exacerbate circadian disruption and "sundowning "
Many medications given to the elderly cause or exacerbate PLMs, which can lead to PLMD or RLS.
DIAGNOSIS
HISTORY
- Episodes of PLMs during sleep (often reported by bed partner) (1)[A]
- Insomnia: difficulty maintaining sleep
- Unrestorative sleep
- Daytime fatigue, tiredness, and/or somnolence
- Oppositional behaviors
- Memory impairment
- Depression
- ADHD, particularly in children
PHYSICAL EXAM
No specific findings
DIFFERENTIAL DIAGNOSIS
- When PLMs occur along with RLS, REM sleep behavior disorder, or narcolepsy, those disorders are diagnosed as "with PLMs, " and PLMD is not diagnosed separately.
- Obstructive sleep apnea: Limb movements (LMs) occur during microarousals from apneas; treatment of sleep apnea eliminates these LMs.
- Sleep starts: nonperiodic, generalized, occur only at wake " sleep transition, <0.2 seconds duration
- Sleep-related leg cramps: isolated and painful
- Fragmentary myoclonus: 75 to 150 ms of EMG activity, minimal movement, no periodicity
- Nocturnal seizures: epileptiform EEG, motor pattern incongruent with PLMs
- Fasciculations, tremor: no sleep association
- Sleep-related rhythmic movement disorder: voluntary movement during wake " sleep transition; higher frequency than PLMs
DIAGNOSTIC TESTS & INTERPRETATION
- Polysomnography with finding of repetitive, stereotyped LMs (1)[A]:
- Tibialis anterior electromyographic (EMG) activity lasting 0.5 to 10 seconds
- EMG amplitude increases >8 ΌV from baseline.
- Movements occur in a sequence of ≥4 at intervals of 5 to 90 seconds.
- Children: ≥5 movements per hour; adults, 15
- Movement may also involve arms.
- Associated with heart rate variability from autonomic-level arousals
- Most PLM episodes occur in the first hours of non-REM sleep.
- Significant night-to-night PLM variability
- Serum ferritin to assess for iron deficiency
Diagnostic Procedures/Other
- Ankle actigraphy for in-home use
- EMG or nerve conduction studies for peripheral neuropathy/radiculopathy
Test Interpretation
Serum ferritin should be > 75 ng/mL.
TREATMENT
Treatment paradigm similar to that for RLS, except that all medications are off-label for PLMD
GENERAL MEASURES
- Daily exercise
- Adequate nightly sleep
- Warm the legs (long socks, leg warmers, electric blanket, etc.).
- Hot bath before bedtime
- Avoid nicotine and evening caffeine and alcohol.
MEDICATION
- Use minimum effective dose.
- Consider risks, side effects, and interactions individually (e.g., benzodiazepines in elderly).
- Daytime sleepiness is unusual with the doses and timing employed for PLMD.
First Line
- Dopamine agonists: Take 1 hour before bed; titrate weekly to optimal dose (1,2)[B]:
- Pramipexole (Mirapex): 0.125 to 0.5 mg; titrate by 0.125 mg
- Ropinirole (Requip): 0.25 to 4 mg; titrate by 0.25 mg
- Transdermal rotigotine (Neupro): 1 to 3 mg/24 hr patch; initiate with 1 mg/24 hr; titrate by 1 mg weekly to effectiveness.
- Avoid dopamine agonists in psychotic patients, especially if taking dopamine antagonists.
Second Line
- Anticonvulsants: useful for associated neuropathy (1,2)[B]:
- Gabapentin enacarbil (Horizant): 600 mg/day
- Pregabalin (Lyrica): 50 to 300 mg/day
- Opioids: low risk for tolerance with bedtime dose
- Hydrocodone: 5 to 20 mg/day
- Oxycodone: 2.5 to 20 mg/day
- Benzodiazepines and agonists (1,2)[B]:
- Clonazepam (Klonopin): 0.5 to 3 mg/day
- Zaleplon, zolpidem, temazepam, triazolam, alprazolam, diazepam
Pediatric Considerations
First-line treatment is nonpharmacologic.
Assess/correct iron deficiency.
Consider low-dose clonidine or clonazepam.
Pregnancy Considerations
Initial approach: iron supplementation, nonpharmacologic therapies
Avoid medications class C or D.
In 3rd trimester, low-dose clonazepam or opioids may be considered.
Geriatric Considerations
In weak or frail patients, avoid medications that may cause dizziness or unsteadiness.
ADDITIONAL THERAPIES
- If iron-deficient, iron supplementation:
- 325 mg ferrous sulfate with 200 mg vitamin C between meals TID
- Repletion may require months.
- Symptoms continue without other treatment.
- Vitamin/mineral supplements, including calcium, magnesium, B12, folate
- Clonidine: 0.05 to 0.1 mg/day
- Relaxis leg vibration device
SURGERY/OTHER PROCEDURES
Correction of orthopedic, neuropathic, or peripheral vascular problems
INPATIENT CONSIDERATIONS
- Control during recovery from orthopedic procedures
- Addition or withdrawal of medications that affect PLMD
- Changes in medical status may require medication changes (e.g., Mirapex contraindicated in renal failure and Requip contraindicated in liver disease).
IV Fluids
- Consider iron infusion when oral supplementation is ineffective, not tolerated, or contraindicated.
- When NPO, consider IV opiates.
Nursing
- Evening walks, hot baths, leg warming
- Sleep interruption risks prolonged wakefulness.
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
- At monthly intervals until stable
- Annual and PRN follow-up thereafter
- If iron-deficient, remeasure ferritin to assess repletion.
DIET
Avoid caffeine and alcohol late in the day.
PATIENT EDUCATION
- National Sleep Foundation: http://sleepfoundation.org/
- American Academy of Sleep Medicine: http://www.sleepeducation.org/
PROGNOSIS
- Primary PLMD: lifelong condition with no current cure
- Secondary PLMD: may subside with resolution of cause(s)
- Current therapies usually control symptoms.
- PLMD often precedes emergence of RLS.
COMPLICATIONS
- Tolerance to medications requiring increased dose or alternatives
- Augmentation (increased PLMs and sleep disturbance, emergence of RLS) from prolonged use of dopamine agonists:
- Higher doses increase risk.
- Iron deficiency increases risk.
- Add alternative medication, then detitrate dopaminergic agent.
- Iatrogenic PLMD (from antidepressants, etc.)
REFERENCES
11 Garcia-Borreguero D, Stillman P, Benes H, et al. Algorithms for the diagnosis and treatment of restless legs syndrome in primary care. BMC Neurol. 2011;11:28.22 Aurora RN, Kristo DA, Bista SR, et al. The treatment of restless legs syndrome and periodic limb movement disorder in adults " an update for 2012: practice parameters with an evidence-based systematic review and meta-analyses: an American Academy of Sleep Medicine Clinical Practice Guideline. Sleep. 2012;35(8):1039 " 1062.
ADDITIONAL READING
- Picchietti DL, Rajendran RR, Wilson MP, et al. Pediatric restless legs syndrome and periodic limb movement disorder: parent-child pairs. Sleep Med. 2009;10(8):925 " 931.
SEE ALSO
Restless Legs Syndrome
CODES
ICD10
G47.61 Periodic limb movement disorder
ICD9
327.51 Periodic limb movement disorder
SNOMED
418763003 periodic limb movement disorder (disorder)
CLINICAL PEARLS
- Many patients with PLMs may not require treatment; however, when sleep disturbance from PLMs causes insomnia and/or daytime consequences, PLMD exists and should be treated.
- Many antidepressants and some antihistamines cause or exacerbate PLMs.
- Sleep disturbance, including that from PLMs, may cause or exacerbate ADHD.