Sleep Medicine

Content In this Page: 
  • Insomnia
  • Shift worker sleep disorder
  • Sleep Apnea 
  • Restless leg syndrome 
  • Narcolepsy 
SLEEP DISORDERS (ICSD 3 divides it into 7 major class)

  • Short-term or Acute Insomnia (<3 month): due to stressors (acute pain, grief)
  • Long-term Insomnia: 
  • Other Insomnia: 
DDx (6 other major class of sleep disorders): Annals 2014
  • Sleep-Related Breathing Disorders (OSA, Central Sleep Apnea)
  • Central Disorders of Hypersomnolence
  • Circadian Rhythm Sleep-Wake Disorders (Time Zone Change Syndrome, Shift work sleep disorder, Delayed Sleep Phase, Advanced Sleep Phase)
  • Parasomnias (related to NREM)
  • Sleep Related Movement Disorder (RLS, PLMD, Nocturnal Cramps)
  • Others
Diagnosis: Short Term vs Chronic vs Other (All 3 features most be present) 
  • Sleep related complaint (initiating sleep, maintaing sleep, early morning awakening, non-restorative sleep)
  • Such complaint occurs despite adequate opportunities to sleep
  • It produces daytime distress or deficits

Insomnia NJEM 2015
    • Medications : 5 major categories 
      • BZD:
        • BZD (Estazolam, Flurazepam, Quazepam, Temazepam, Triazolam)
        • Non-BZD sedatives (Eszopiclone, Zopicolone, Zaleplon, Zolpidem)
      • Anti-depressants (Amitriptyline, Doxepin, Mirtrazapine, Trazodone)
      • Orexin antagonists (suvorexent) 
      • Melatonin agonists (Ramelteon, Melatonin, Prolonged Release)
      • Anticonvulsants - Clonazepam, Gabapentin; 
      • Other: Anti-psychotics - Olanzapine, Quetiapine
    • Duration of action (see above Chart): 
      • Sonata (s = short acting), < Ambien < Lunesta (l = long acting) < Tenazepam 
    • Sleep onset insomnia : Short Acting (Triazolam, Zaleplon or Sonata, Zolpidem)
      • Reduce sleep latency
    • Sleep maintenance insomnia: longer acting medicationsZolpidem extended release, eszipiclone or Lunesta or ultra-short acting (Zaleplon or Sonata)
      • Longer acting formulations have hangover lasting into the day, but ultra-short acting formulation does not have this concern
    • OTC agent: 
      • Anti-histaminics (Unisom, Aldex AN, Benadryl)
        • Diphenhydramine
        • Doxylamine succinate
        • Note: Even though they are used, they should be avoided due to adverse effects and lack of data on its efficacy 
      • Melatonin agonists (Ramelteon, Melatonin, Prolonged Release)
        • Improves sleep onset, duration, quality. Also, improves REM sleep (Ref:Chapter 64 13e) . However, per Lancet 2012 efficacy is inconclusive and reduces sleep latency by only 7.2 min. Some positive evidence is for delayed sleep phase, and shift work sleep disorder
        • Melatonin:
          • Effective in patients with Insomnia due to Beta Blockers.
          • 0.3–10 mg of the immediate-release formulation given orally once nightly
          • lowest effective dose should be used first and may be repeated in 30 minutes up to a maximum of 10–20 mg
          • sustained released formulation are effective but inferior to immediate release formulation 
        • Ramelteon
          • Minimal side effects, no abuse concern
    • Hypnotic Agents:
      • BZD (Estazolam, Flurazepam, Quazepam, Temazepam, Triazolam)
      • Non-BZD sedatives : Eszopiclone, Zopicolone, Zaleplon, Zolpidem (ambien)
        • Eszopiclone (Lunesta)
          • Improves insomnia when given with SSRI
            • with Fluoxetine for MDD
            • with Escitalopram for GAD 
      • Anti-depressants (Amitriptyline, Doxepin, Mirtrazapine, Trazodone)
      • Others (Anticonvulsants - Clonazepam, Gabapentin; Anti-psychotics - Olanzapine, Quetiapine)


    Pharmacological Interventions for Sleepiness and Sleep Disturbances Caused by Shift Work JAMA 2015

    • Few Terms: BMJ 2014
      • Apnea:  cessation, or near cessation of airflow. Airflow reduced to less than 10% (90 % or more reduction) of baseline for more than 10 s; obstructive if respiratory effort is present  (due to complete pharyngeal collapse), central if no respiratory effort is present (no obstruction is present) Lancet 2014
      • Hypopnea: reduction of airflow but does not meet the criteria of apnea definition. Airflow decreases at least 30% of baseline for more than 10 s, in association with a 4% (3% by new definition) oxygen desaturation (due to partial pharyngeal collapse) Lancet 2014
      • Apnea / Hypopnea Index (AHI): Number of respiratory events /hr
    • Definition of OSAS:  BMJ 2014
      • AHI > 5 with associated symptoms of sleep fragmentation 
          • Typically, AHI > 5 is associated with symptoms of excessive symptoms of daytime sleepiness. Hence, cutoff of AHI > 5 is used. 
          • Daytimes Symptoms of Sleep Fragmentation: 
            • Sleepiness, Fatigue, Poor Concentration
          • Signs of sleep fragmentation: Snoring, restlessness, or resuscitative snorts
    • Pathogenesis: BMJ 2014
      • Anatomy of OSAS
        • Loss of phyrangeal dilator muscle tone (causes airway narrowing)
        • Retropositioning of the Mandible 
        • Narrowing of the lateral phyrangeal wall by fat pads 
      • Neurohormonal Changes of OSAS
        • Autonomic activation to airway obstruction reestablishes the tone and terminates obstruction
      • Sleep related changes
        • Patient with OSAS spend less time in REM (Rapid Eye Movement) Sleep and Restorative Slow wave sleep 
    • Indications for a referral for a sleep study BMJ 2014
      • Symptoms of excessive sleepiness or an Epworth sleepiness score of ≥11*
      • Recurrent witnessed apneas 
      • Nocturnal choking, gasping, or “dyspnoea”
      • Headache in the morning
      • Unrefreshing sleep despite adequate sleep time and continuity
      • Near miss events or incidents caused by reduced vigilance while driving*
      • Screening before bariatric surgery or upper airway surgery for snoring
      • Otherwise unexplained polycythaemia, pulmonary hypertension, or ventilatory failure
      • Note: Urgent referral is necessary if the Epworth sleepiness score is >18 or the patient has had a road traffic incident or near miss event 
    • Screening Tests for Sleep Apnea:
      • ESS
      • STOP-Bang
    • Tests for OSAS
      • Overnight oximetry 
      • Overnight polysomnography (monitors following 6 areas)
        • Monitoring of Sleep-Wake State
          • EEG (sleep stages) 
            • N3, REM is often absent or reduced in OSA
            • Wake, N1, N2 often increased in OSA  
          • L and R electrooculogram 
          • Chin electromyogram
        • Respiratory effort measurement
          • respiratory inductance plethysmography bands placed around the thorax and abdomen
        • Airflow monitoring
          • nasal air pressure
          • thermal air sensor
          • arterial Oxygen saturation
        • Limb movement assessment
          • EMG of anterior tibialis
        • Body position
        • EKG
    • Severity
      • Mild OSA: 5-15 AHI
      • Moderate OSA: 15 - 30 AHI
      • Severe OSA: > 30 AHI
    • References:
    RESTLESS LEG SYNDROME: Primary (or Idiopathic; 40% have family history ) vs. Secondary (Iron deficiency, ESRD, DM, MS, PD, Pregnancy, Rheumatic Disease, Venous Insufficiency, Drugs