Study Notes on Sleep Apnea and Related Disorders

Sleep apnea is a disorder associated with breathing interruptions during sleep.
Often occurs in the upper airway, leading to sustained breathing issues and potential health complications.

Sleep apnea is prevalent among individuals, particularly as they gain weight.
Increased weight can exert pressure on the respiratory apparatus, compromising the upper airway during sleep.
Common physical contributors include:
- Enlarged nasal turbinates
- Nasal polyps
- Macroglossia (enlarged tongue) which can block the airway when it falls back during sleep.

Apnea and Hypoxia:
- Multiple episodes of apnea or hyperapnea can lead to hypoxia (reduced oxygen) and hypercapnia (increased carbon dioxide).
- This negatively impacts both Non-REM and REM sleep stages.
Sleep Stages:
- Sleep is categorized into four phases, including:
- REM Sleep: Characterized by rapid eye movement; typically occurs 45 minutes after sleep onset and is associated with dreaming.
- Non-REM Sleep: Consists of deeper sleep stages following REM; sleep apnea can interrupt both types of sleep.

Common symptoms include excessive daytime fatigue, loud disruptive snoring, and choking or gasping at night.
Patients often wake feeling unrefreshed and may have a dry throat or headache due to hypoxia.

Increased risk factors include:
- Obesity
- Alcohol or sedative use
- Post-menopausal status
- Medical conditions such as:
- Acromegaly associated with Cushing's Disease
- Hypothyroidism
- Gastroesophageal reflux
- History of strokes or nocturnal angina.
Hypertension and Cardiovascular Risks:
- Patients have a greater risk for hypertension, heart failure, and atrial fibrillation.
- Increased incidence of non-alcoholic fatty liver disease, linked to high-fat diets affecting liver function.

Diagnosis typically includes:
- Apnea-Hypoapnea Index (AHI): Measures episodes of apnea and hypopnea during sleep.
- Sleep Study (Polysomnography): Monitors sleep patterns, including EEG, chin electromyography, and oxygen saturation.
- Respiratory Disturbance Index (RDI): Measures arousal periods during respiratory effort.
- Home Sleep Tests: Portable units can provide data on heart rate, oxygen levels, and respiratory effort.

Lifestyle Modifications:
- Address obesity through weight reduction and management of blood pressure.
- Recommendations may include cessation of alcohol use.
Medical Devices:
- CPAP (Continuous Positive Airway Pressure) Machines:
- Maintain open airways by providing air pressure; have evolved from large devices to more manageable options.
- Oral CPAP machines are available for specific cases.
Surgical Options:
- Removal of tonsils, nasal polyps, or portions of the tongue to reduce airway obstruction.
- Surgical advancement of the hyoid bone may also improve airway patency.
Medications:
- Drugs like theophylline or acetazolamide can increase respiratory drive and reduce airway collapsibility.

A condition characterized by:
- Alveolar hypoventilation, specifically in individuals with obesity (BMI > 30).
- Stages of Pickwickian syndrome range from non-hypercapnic (Stage 0) to stages with obesity-related sleep hypoventilation (Stages 1-4).

Complications of Sleep Apnea:
- Hypertension
- Increased risk of cardiovascular issues
Complications of Obesity Hypoventilation Syndrome:
- Chronic respiratory failure
- Pulmonary hypertension
- Endocrine disorders and hypertension.

The importance of comprehensive evaluations for both conditions.
Bariatric surgery options include:
- Sleeve surgery (removal of a significant portion of the stomach)
- Roux-en-Y surgery (rerouting intestines).
New medications like GLP-1 receptor agonists (e.g., Ozempic) reduce appetite and assist with weight loss but require lifestyle changes for sustainability.