Neurosurgery notes/Other specialities/Neurology/Neurology general/Sleep/Sleep abnormalities

Sleep abnormalities

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Sleep

Sleep deprivation

  • Widespread effects on metabolism, hormone secretion, and brain function
  • In rats, causes death in a few weeks.
  • When sleep eventually ensues, the time in stage 4 increases.
  • Monoamine oxidase inhibitors increase NE and suppress REM sleep.

Insomnia

  • Benzodiazepines
    • Increase stage 2 duration as well as number of sleep cycles.
    • REM sleep is decreased.
  • Hypnotics (zolpidem)
    • Do not decrease REM sleep duration as much as benzodiazepines.

Restless leg syndrome

  • About 10 to 15% of the population
  • No gender predominance.
  • Akisthesia ( inability to remain still.) of lower extremities secondary to paresthesias.
    • Temporally relieved by movement.
  • Aetiology
    • A common genetic variant that increases risk for the condition.
    • Can develop secondary to
      • Iron deficiency,
      • Peripheral neuropathy,
      • Peripheral vascular disease (PVD).
  • Treatment
    • DA agonists.
    • Fe2+ supplementation.
    • Opiates.
    • Gabapentin.

Night terrors

  • Mainly in childhood.
  • More common in boys;
    • It remits with adolescence.
  • Occurs in stage 3 or 4 sleep;
    • Onset is 30 minutes after falling asleep.
  • Typically no memory of precipitating event.
  • Treatment with benzodiazepines to decrease stage 4 sleep.

Nightmares

  • Occur in children and adults during REM sleep.

Difference between nightmares and night terrors

Nightmares
Night Terrors
When they occur
During the REM (rapid eye movement) phase of sleep, usually in the last third of the night
During the NREM (non-rapid eye movement) phase of sleep, usually during slow-wave sleep and typically in the first third of the night
What happens
Involve intense dreams that may provoke fear, anger, or disgust
Involve episodes where the person partially wakes from sleep and may scream, thrash about, or jump out of bed
Upon waking
Can remember the dream
Difficult to wake and may be confused for several minutes
Who it affects
Can affect both children and adults
Most common in children between the ages of 3 and 8

Parasomnias

  • Undesirable motor, verbal, or experiential events during sleep.

Somnambulism (sleepwalking)

  • Usually at 4 to 6 years.
  • No gender predominance.
  • Occurs during stage 4 sleep in the first third of the night.
    • May be a disorder of slow-wave sleep.
    • Associated with enuresis and night terrors.
  • 15% of children have one episode and 20% have a family history.
  • Treatment
    • Lorazepam.
    • Tricyclic antidepressants.

REM sleep behaviour disorder

  • Most common in older men; may precede Parkinson’s disease.
  • Paralysis normally seen with REM sleep is diminished or absent. Patients “act out” their dreams typically with violent behaviour.
  • There is vivid recall of the inciting dream.

Nocturnal epilepsy

  • Occurs mainly during stage 4 and REM.

Hypersomnia

  • Associated with
    • Trypanosomiasis,
    • Hypercarbia,
    • Myxedema,
    • Lesions in the midbrain or t­halamus.

Sleep apnea

  • Transient arrest of breathing during sleep that lasts more than 10 seconds and occur more than 5 times per hour.
  • Central sleep apnea is caused by lower medullary lesions.
  • Obstructive sleep apnea is caused by soft tissues surrounding the airway such as the tongue, tonsillar hypertrophy
    • Typically seen in obese middle-aged men, especially those with acromegaly.
    • Associated with noisy snoring and daytime somnolence.
  • Treatment
    • Continuous positive airway pressure
    • Sleeping in the lateral position.
    • Avoidance of ethanol
    • Surgical resection of soft tissue.

Narcolepsy

  • Peak age 15 to 35 years, no sex predominance, strongly associated with HLA-DR2.
  • Classic tetrad
    • Excessive daytime sleepiness—may fall asleep while eating, talking.
    • Cataplexy—sudden loss of muscle tone with no loss of consciousness elicited by emotion.
    • Hypnagogic (upon sleep onset) or hypnopompic (upon waking) hallucinations.
    • Sleep paralysis—paralysis on awakening, sparing eyes, and breathing function.
  • Due to destruction of hypothalamic hypocretin/orexin neurons, which stimulate ACh, monoamine and histaminergic systems of ARAS.
  • 70% develop cataplexy. All patients with cataplexy have narcolepsy.
  • Treatment
    • Scheduled naps.
    • Amphetamines.
    • Amitriptyline (for cataplexy).

Enuresis

  • Male predominance; peak age 4 to 14 years.
  • Family history is common;
  • Can be secondary to numerous causes (diabetes, cystitis, structural anomalies),
    • Must be ruled out.
  • Treatment
    • Desmopressin acetate (DDAVP).
    • Anticholinergics.
    • Imipramine.