Hypersomnolence Disorders

On this page

Hypersomnolence: Overview - Sleepy Saga Starts

Causes of Excessive Daytime Sleepiness

  • Excessive Daytime Sleepiness (EDS): Primary symptom.
  • Difficulty waking up (sleep inertia/drunkenness).
  • Unrefreshing naps, despite normal or prolonged sleep duration.
  • Not due to insufficient sleep, circadian rhythm disorders, other sleep disorders (e.g., OSA), medical/psychiatric conditions, or substances.

⭐ Central disorders of hypersomnolence are characterized by Excessive Daytime Sleepiness (EDS) despite normal or long sleep duration, not better explained by other sleep, medical, psychiatric disorders, or substance use.

  • Impacts daily functioning, cognition, and mood significantly.
  • Diagnosis involves clinical assessment, sleep diaries, actigraphy, Polysomnography (PSG), and Multiple Sleep Latency Test (MSLT).

Narcolepsy: Deep Dive - Attack of the Zzzs

Impaired sleep-wake cycle regulation.

  • Classic Tetrad (📌 CHESS):
    • Cataplexy: Emotion-triggered muscle weakness (NT1).
    • Hallucinations (Hypnagogic/Hypnopompic).
    • EDS: "Sleep attacks".
    • Sleep Paralysis.
  • Types:
    • NT1: EDS + Cataplexy OR ↓CSF hypocretin-1.
    • NT2: EDS, no cataplexy, normal CSF hypocretin-1.
  • Pathophysiology: ↓Hypocretin (orexin) from neuronal loss (autoimmune).

⭐ Narcolepsy Type 1 is strongly associated with HLA-DQB1*06:02 and low CSF hypocretin-1 levels (typically <110 pg/mL or <1/3 of mean control values).

  • Diagnosis:
    • PSG + MSLT.
    • MSLT: Sleep latency ≤8 min; ≥2 SOREMPs.
  • Management:
    • EDS: Modafinil, stimulants, pitolisant.
    • Cataplexy: Na-oxybate, TCAs, SSRIs/SNRIs.

Idiopathic Hypersomnia & KLS - The Long Sleepers

  • Idiopathic Hypersomnia (IH)
    • Chronic EDS despite normal/long sleep (≥7h).
    • Unrefreshing naps; severe sleep inertia (difficulty waking).
    • PSG: normal/long sleep. MSLT: mean sleep latency <8 min, ≤1 SOREM.
    • Diagnosis of exclusion.
    • Tx: Modafinil, stimulants, pitolisant, sodium oxybate.
  • Kleine-Levin Syndrome (KLS)
    • Rare "Sleeping Beauty Syndrome".
    • Recurrent hypersomnia (days-weeks), cognitive & behavioral changes.
    • Adolescent males primarily; normal between episodes.
    • Tx: Supportive; Lithium for prophylaxis.

    ⭐ Kleine-Levin Syndrome is characterized by recurrent episodes of hypersomnia (≥2 days to weeks), cognitive disturbances (e.g., derealization), and behavioral changes (e.g., hyperphagia, hypersexuality), predominantly affecting adolescent males.

Hypersomnolence: Dx & Rx - Waking Up Plan

  • Diagnostic Criteria:
    • Narcolepsy: MSLT mean sleep latency ≤ 8 min AND ≥ 2 SOREMPs (Sleep Onset REM Periods).
    • Idiopathic Hypersomnia (IH): MSLT mean sleep latency ≤ 8 min AND < 2 SOREMPs; OR total 24-hr sleep time ≥ 11 hrs (via diary/actigraphy) or PSG nocturnal sleep ≥ 10 hrs.
  • Treatment Principles:
    • Non-Pharmacological: Sleep hygiene, scheduled naps (esp. for Narcolepsy, e.g., 15-20 min).
    • Pharmacological (EDS):
      • Modafinil/Armodafinil (first-line).
      • Methylphenidate, Amphetamines.
      • Newer: Solriamfetol, Pitolisant.
    • Cataplexy (Narcolepsy Type 1):
      • Sodium oxybate.
      • TCAs (e.g., Imipramine), SSRIs/SNRIs (e.g., Venlafaxine).

⭐ Modafinil is a first-line pharmacological treatment for excessive daytime sleepiness in narcolepsy and idiopathic hypersomnia due to its efficacy and generally favorable side-effect profile.

High‑Yield Points - ⚡ Biggest Takeaways

  • Narcolepsy: EDS, cataplexy, hallucinations, sleep paralysis; HLA-DQB1*06:02, low hypocretin.
  • Idiopathic Hypersomnia: EDS, long unrefreshing naps, no cataplexy.
  • Kleine-Levin Syndrome: Recurrent hypersomnia with cognitive/behavioral disturbances.
  • MSLT diagnosis: Narcolepsy: mean sleep latency ≤8 min, ≥2 SOREMPs. Idiopathic: ≤8 min, <2 SOREMPs.
  • Modafinil/Armodafinil for EDS in narcolepsy & idiopathic hypersomnia.
  • Sodium oxybate treats cataplexy and EDS in narcolepsy_._

Practice Questions: Hypersomnolence Disorders

Test your understanding with these related questions

A 40-year-old man presents with daytime sleepiness and impaired concentration and memory. On examination his BMI is 41 kg/m2, BP is 160/100 mm Hg. His awake ABG analysis is given: PaO2=66 mm Hg, PaCO2=50 mm Hg, HCO3=28 mEq/L. What is the most likely diagnosis?

1 of 5

Flashcards: Hypersomnolence Disorders

1/9

Multiple sleep latency test (MSLT) records Electroencephalographic, electro-oculographic, and sub-mental electromyography activity to determine sleep _____

TAP TO REVEAL ANSWER

Multiple sleep latency test (MSLT) records Electroencephalographic, electro-oculographic, and sub-mental electromyography activity to determine sleep _____

stage

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial