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Anatomic and functional lesions resulting in partial or complete upper airway obstruction.

HE CAUSES OF upper airway obstruction are many and varied. The clinical presentation (acute over hours, or chronically over days to weeks), as well as the age of the patient are important in distinguishing among the various causes of airway obstruction. In pediatric patients, congenital airway anomalies (laryngeal malacia, subglottic stenosis, laryngeal webs, and vascular rings) are the most common cause, whereas in adults, malignant neoplasms of the aerodigestive tract dominate (Figs 1 through 3). Other causes of stridor and upper airway obstruction include inhalational burns, foreign body aspiration, subglottic edema due to anaphylaxis or intubation, recurrent laryngeal nerve paralysis, and local compression by tumor. Importantly, many of these entities are best assessed by indirect or direct visualization/ laryngoscopy; however, radiologic imaging using plain films, CT, or MR may provide valuable and diagnostic information. In this article, the causes of upper airway obstruction and their workup and management are discussed. Importantly, the role of imaging in establishing the diagnosis as well as specific causes of airway obstruction are also addressed. Emphasis is on when to use imaging in suspected airway obstruction, rather than on specific radiologic findings, because imaging is frequently obtained only following management of the airway. In assessing upper airway obstruction in children, congenital malformations and developmental anomalies, aspirated foreign bodies, epiglottis, and masses in the soft tissues of the neck are most commonly encountered. In children, extralaryngeal masses that may cause secondary airway obstruction include benign neoplasms, such as plexiform neurofibromas, lymphangiomas, hemangiomas, and subglottic teratomas. 1 Many congenital malformations involving the