Pharyngeal size in snorers and patients with obstructive sleep apnea is reduced compared with that in nonsnorers, with sleep apnea patients having the smallest cross-sectional pharyngeal area. The sound of snoring originates in the collapsible portion of the airway—the soft tissue between the choanae and the epiglottis. Tone in the lingual and pharyngeal muscles may be inadequate due to use of sedatives or alcohol. Structural abnormalities may contribute and include redundant or thickened lateral pharyngeal musculature, a long uvula, thickened pharyngeal folds, and flaccid tonsillar pillars. Large tonsils, cysts, or neoplasms sometimes may obstruct the airway. Mild maxillomandibular abnormalities, such as a small chin, overbite, and high hard palate, have been found to be important in women. Obstructing nasal abnormalities (e.g., severely deviated septum, polyps, sinusitis, neoplasm) may create excessive negative pressure with turbulent airflow and cause the collapse of the airway during inspiration.

Severe airway obstruction may lead to sleep apnea. Full obstruction interrupts ventilation and, if sufficiently prolonged and repeated, results in hypercarbia and hypoxemia. The restoration of breathing usually requires arousal from sleep. The nightly occurrence of multiple apneic episodes and disturbed sleep pattern causes daytime tiredness and hypersomnolence. Uncorrected, the condition may lead to cor pulmonale from chronic arterial desaturation. The condition is most common in obese patients but is not restricted to them (see Chapter 46).

The history is most important, especially for recognition of sleep apnea. Habitual snoring, daytime sleepiness, history of motor vehicle accidents caused by falling asleep at the wheel, or witnessed apneas should trigger concern about sleep apnea. Because the condition is most common in men, with a 3:1 ratio, women with sleep apnea often go unrecognized. Delay in the diagnosis of sleep apnea is common, especially in women, because symptoms are often ignored or the presentation may be atypical (fatigue, no associated obesity or daytime sleepiness, mild maxillomandibular abnormalities). Factors associated with an increased risk for sleep apnea in snoring patients include large collar size, associated hypertension, heroic snoring (i.e., snoring that can be heard outside the bedroom), and daytime somnolence.