History and exam

Key diagnostic factors

common

poor sleep

PLMD is frequently associated with nocturnal arousals of which patients are aware. Patients frequently report feeling unrefreshed following sleep.

daytime impairment

PLMD is associated with subjective diminished physical and psychological fitness on awakening, and with symptoms of daytime sleepiness, fatigue, and poor performance at work.

periodic limb movements (mostly legs)

The limb movements experienced in PLMD may be reported as the presenting symptom by the patient, but more often by the bed partner. Partners sleeping in the same bed may be woken by these limb movements.

Other diagnostic factors

common

age >70 years

PLMD can occur at any age. Prevalence increases with age.[17]

re-enactment of dreams during the night

PLMD has been reported to occur in rapid eye movement sleep behaviour disorder: body movements may occur as dreams and are re-enacted during rapid eye movement sleep.

uncommon

irresistible urge to move legs, and abnormal sensations in lower limbs

The prevalence of PLMD is as high as 80% in individuals with restless legs syndrome (RLS). Patients with RLS have an irresistible urge to move their legs, and unpleasant sensory symptoms in the lower limbs, with symptoms worse in the evening and at night. RLS is troublesome during wakefulness, whereas PLMD usually occurs during sleep.

snoring

PLMD has been associated with sleep apnoea syndrome. A history of snoring may be supportive.

early-morning dry mouth

PLMD has been associated with sleep apnoea syndrome. A history of early-morning dry mouth may be supportive.

headache

PLMD has been associated with sleep apnoea syndrome. A history of headache may be supportive.

elevated body mass index

PLMD has been associated with sleep apnoea syndrome. A history of elevated body mass index may be supportive.

withdrawal from benzodiazepines or barbiturates

PLMD has been reported to occur in individuals withdrawing from benzodiazepine or barbiturate therapy. A thorough drug history is therefore important.

use of antipsychotics

PLMD has been reported to occur in individuals taking antipsychotics. A thorough drug history is therefore important.

use of dopaminergic drugs

PLMD has been reported to occur in individuals taking dopaminergic drugs. A thorough drug history is therefore important.

pallor

PLMD has been reported to occur in individuals with anaemia, particularly if related to iron deficiency.

iron deficiency

PLMD has been reported to occur in individuals with iron deficiency. In PLMD associated with RLS, iron replacement is widely recommended if levels are <101 pmol/L (<45 micrograms/L or 45 nanograms/mL) (normal range for adults is 45-674 pmol/L [20-300 micrograms/L or 20-300 nanograms/mL] for men and 45-337 pmol/L [20-150 micrograms/L or 20-150 nanograms/mL] for women), as patients may experience symptoms when ferritin is in the low to normal range.[28]

diabetes mellitus

PLMD has been reported to occur in individuals with diabetes mellitus.

spinal cord injury

PLMD has been reported to occur in individuals with spinal cord injury.

episodes of sudden onset of sleep during the day; may or may not be associated with loss of muscle tone

PLMD has been reported to occur in individuals with narcolepsy.

Risk factors

weak

age >70 years

PLMD can occur at any age. Prevalence; however, appears to increase with age.[17]

female sex

PLMD occurs in both sexes. One large population-based study suggested a modest female preponderance, but two smaller population-based studies suggest a reduced prevalence in women.[15][16][26]

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