Breathing-Related Sleep Disorders

Breathing-Related Sleep Disorders

Breathing-Related Sleep Disorders

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  • Disorders characterized by abnormal respiration during sleep.
  • Types:
    • Obstructive Sleep Apnea (OSA): Most common.
    • Central Sleep Apnea (CSA).
    • Sleep-Related Hypoventilation Disorders.
    • Sleep-Related Hypoxemia Disorder.
  • Obstructive Sleep Apnea (OSA):
    • Pathophysiology: Recurrent episodes of partial/complete upper airway obstruction during sleep → intermittent hypoxia, hypercapnia, sleep fragmentation.
    • Risk factors: Obesity (BMI >30 kg/m²), male, age, craniofacial abnormalities, smoking.
    • Symptoms: Loud snoring, witnessed apneas, daytime sleepiness.

Non-obstructed vs. obstructed airway in sleep apnea

⭐ OSA is a major risk factor for hypertension, cardiovascular disease, and stroke. Apnea-Hypopnea Index (AHI) >5 events/hour is diagnostic; >15 moderate; >30 severe.

  • Clinical Drama (Symptoms):

    • Loud habitual snoring, choking/gasping episodes during sleep.
    • Witnessed apneas reported by bed partner.
    • Excessive Daytime Sleepiness (EDS); assess with Epworth Sleepiness Scale (ESS >10 is significant).
    • Morning headaches, non-restorative sleep, fatigue, impaired concentration.
    • 📌 Mnemonic STOP-BANG for OSA screening: Snoring, Tiredness, Observed apnea, high blood Pressure, BMI >35 kg/m², Age >50 yrs, Neck circumference >40cm, Gender male.
  • Diagnostic Evaluation:

    • Polysomnography (PSG): Gold standard diagnostic test.
      • Records: EEG (sleep staging), EOG (eye movements), EMG (muscle tone), ECG, airflow (nasal/oral), respiratory effort (chest/abdomen), SaO2 (pulse oximetry).
    • Key parameter: Apnea-Hypopnea Index (AHI) = (Total apneas + hypopneas) / Total sleep time in hours.
      • Apnea: Cessation of airflow ≥10 seconds.
      • Hypopnea: Reduction in airflow ≥30% for ≥10 seconds associated with ≥3% oxygen desaturation or an arousal.
    • AHI Severity for OSA (Adults):
      • Mild: AHI 5-14 events/hour.
      • Moderate: AHI 15-29 events/hour.
      • Severe: AHI ≥30 events/hour.

⭐ Untreated Obstructive Sleep Apnea (OSA) is a significant independent risk factor for systemic hypertension, cardiovascular disease (e.g., CAD, arrhythmias, heart failure), stroke, and type 2 diabetes mellitus.

Apnea event: airflow, SpO2, heart rate

  • Goal: Prevent pharyngeal collapse, normalize breathing.
  • Lifestyle: Weight loss, avoid alcohol/sedatives, positional therapy.
  • CPAP (Pneumatic Splint):
    • 1st line for Mod-Severe OSA (AHI ≥ 15).
    • Maintains airway patency. Adherence vital.
  • Alternatives:
    • Oral Appliances (MADs): Mild-Mod OSA, CPAP intolerance.
    • Surgery (UPPP, MMA): Anatomical issues. Tracheostomy (last resort).
  • Risks (Untreated): HTN, arrhythmia, CVA, daytime somnolence.

    ⭐ CPAP adherence significantly reduces cardiovascular morbidity in OSA patients.

Pathophysiology of Obstructive Sleep Apnea

  • Obstructive Sleep Apnea (OSA): Upper airway collapse.
    • Symptoms: Snoring, daytime sleepiness, apneas. 📌 STOP-BANG risk.
    • Dx: Polysomnography (PSG) AHI ≥ 15 or ≥ 5 + symptoms.
    • Rx: CPAP, weight loss.
  • Central Sleep Apnea (CSA): ↓/Absent ventilatory effort.
    • Types: Idiopathic, Cheyne-Stokes (HF, stroke), opioid-induced.
    • Dx: PSG shows central apneas.
    • Rx: Treat cause, ASV, BiPAP.
  • Sleep-Related Hypoventilation: ↑PaCO2 in sleep.
    • Causes: Obesity Hypoventilation Syndrome (OHS), neuromuscular disease.
    • Dx: PSG: sustained ↑PaCO2 (> 55 mmHg).
    • Rx: NIV (BiPAP), treat cause. Polysomnography: Obstructive vs Central Apnea Tracing

⭐ Cheyne-Stokes respiration, a pattern of CSA, is frequently seen in patients with congestive heart failure.

High‑Yield Points - ⚡ Biggest Takeaways

  • Obstructive Sleep Apnea (OSA): most common, due to recurrent upper airway collapse during sleep.
  • Major OSA risk factors: obesity (↑BMI), male gender, older age, large neck circumference.
  • Polysomnography (PSG) is the diagnostic gold standard; measures Apnea-Hypopnea Index (AHI).
  • AHI >5 events/hour confirms diagnosis; CPAP is first-line for moderate-severe OSA (AHI ≥15).
  • Central Sleep Apnea (CSA): cessation of airflow due to absent/reduced respiratory effort.
  • Obesity Hypoventilation Syndrome (OHS): triad of obesity, daytime hypercapnia, and sleep-disordered breathing.

Practice Questions: Breathing-Related Sleep Disorders

Test your understanding with these related questions

A 56-year-old woman with diabetes, hypertension, and hyperlipidemia is found to have an A1C of 11 despite her best attempts at diet and faithfully taking her metformin and glyburide. She reports severe fatigue and sleepiness in the daytime, which has limited her ability to exercise. On examination, she is obese, has a full appearing posterior pharynx, clear lungs, a normal heart examination, and trace bilateral edema. Her TSH is 2.0 m/L (normal). Before adding another oral agent or switching to insulin, what is the best next step?

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Flashcards: Breathing-Related Sleep Disorders

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Somnambulism (sleepwalking) is seen in 4-8 year old children and usually _____ after adolescence

TAP TO REVEAL ANSWER

Somnambulism (sleepwalking) is seen in 4-8 year old children and usually _____ after adolescence

resolves::Resolves/Worsens

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