Obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is a common, potentially serious sleep disorder. It causes breathing to repeatedly stop and start during sleep. It is most common in adult males and postmenopausal women. Risk factors include older age, male gender, obesity, and upper airway abnormalities.

Clinical Features

• Daytime sleepiness
  • May be underestimated due to chronic nature, insidious onset
• Loud snoring, gasping, interruptions in breathing while sleeping
  • Usually history obtained from patient's bed partner

Differential Diagnosis

• Excessive daytime sleepiness
  • Insufficient sleep - shift work, underlying comorbidity, medication affects
  • Sleep disorders - circadian rhythm sleep-wake disorder, narcolepsy
  • Sleep related movement disorder - restless legs syndrome, periodic limb movement disorder
• Abrupt awakening or abnormal sounds during sleep
  • Primary snoring - Most patients who have OSA snore, but most patients who snore do not have OSA.
  • Gastroesophageal reflux disease - Can produce a choking sensation and dyspnea at night
  • Nocturnal asthma
  • Nocturnal seizure
• Early morning headaches
  • Space occupying lesions of the brain - consider brain imaging
  • Obesity hypoventilation - would potentially show hypercapnia/hypercarbia on venous blood gas

Evaluation

OSA is not a clinical diagnosis and objective testing must be performed for diagnosis. Consider diagnostic testing with patients with excessive day time sleepiness (EDS) on most days and two of the following clinical features: habitual loud snoring, witnessed apnea or gasping or choking during sleep, and diagnosed systemic hypertension.

• Evaluation tool parameters: No evaluation tools have been shown to be superior to history and physical examination and their poor accuracy make them imperfect diagnostic tools, but are often used in preoperative evaluation to assess risk of undiagnosed OSA
  • STOP-Bang questionnaire
  • Epworth Sleepiness Scale
• Polysomnography: gold standard diagnostic test for OSA. Preferred in-lab testing for those with suspected concomitant respiratory disorder (e.g. COPD), concomitant sleep disorder(e.g. narcolepsy), mild disease, negative or inconclusive home testing
• Home sleep apnea testing: Good for patients with high pretest probability for moderate to severe uncomplicated OSA.