Obstructive Sleep Apnea Syndrome: Causes

Pathogenesis (disease development)

Snoring in obstructive sleep apnea syndrome (OSAS) occurs when the upper airway closes during sleep due to muscle relaxation (= collapse of the oropharyngeal pharyngeal muscles). In addition to anatomic factors, non-anatomic factors also play a significant role in the development of OSAS. Non-anatomical factors include unstable respiratory control (“high loop gain”, LG), ineffective upper airway dilator function during sleep, and low threshold respiratory arousals (so-called arousal responses).

Anatomical abnormalities are more likely to be found in younger OSAS patients, and functional abnormalities are more likely to be found in older patients, and often the two complement each other in an unfavorable manner.

This leads to increasingly severe hypoxia (reduced supply of oxygen to the body) or asphyxia (impending suffocation due to a drop in arterial oxygen content). Only the resulting hypercapnia (increased carbon dioxide content in the blood) leads to microarousals (arousal reactions), in which the musculature is toned again and sufficient (adequate) breathing is possible.

Because these breathing interruptions can occur several hundred times per night, restorative sleep is lacking and daytime sleepiness occurs.

Etiology (causes)

Biographic causes

  • Anatomic variants of the upper airway such as a jaw that is too small.
  • Increased neck circumference
  • Age/Hormonal Factors – The condition occurs predominantly in middle age in men and usually after menopause (female menopause) in women.

Behavioral causes

  • Nutrition
  • Consumption of stimulants
    • Alcohol (evening consumption)
  • Drug use
    • Ecstasy (also XTC, Molly, etc.) – methylenedioxymethylamphetamine (MDMA); dosage on average 80 mg (1-700 mg); structurally belongs to the group of amphetamines.
  • Sitting in front of the TV
  • Sleeping in the supine position
  • Overweight (BMI ≥ 25; obesity) (about 80% of patients with obstructive sleep apnea syndrome).

Disease-related causes

  • Hyperplasia (enlargement due to proliferation of normal cells) of the palatine and/or pharyngeal tonsils – as a cause of obstructive sleep apnea syndrome (OSAS) in children.
  • Hypertension (high blood pressure)
  • Laryngeal stenosis – narrowing of the larynx.
  • Macroglossia – enlargement of the tongue.
  • Nasal polyps – benign growths of the nasal mucosa.
  • Nasal septum deviation – curvature of the nasal septum.
  • Rhinitis (rhinitis) with restricted nasal breathing.
  • Tumors in the nasopharynx
  • Tonsillar hyperplasia – enlargement of the palatine tonsils.

Medication

Other causes

  • Gravidity (pregnancy) – about 10% of pregnant women temporarily develop OSAS.