Hypersomnolence Disorders

Hypersomnolence: Overview - Sleepy Saga Starts

• 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_._