Upper airway obstruction is a narrowing of the oropharynx, larynx, or trachea. It is often a medical emergency.

• In children, upper airway obstruction is primarily allergic, infectious (croup, epiglottitis, abscess), or caused by foreign body aspiration.
• While adults may also suffer from upper airway obstruction of an infectious etiology, it is more commonly caused by malignancy, trauma, or inflammatory diseases.

The subsite of the obstruction may be a helpful indication of its cause:

• The supraglottic region can be obstructed by croup, supraglottitis, epiglottitis, neck abscess, Ludwig angina, or angioedema.
• The glottic region can be obstructed iatrogenically (eg, prolonged intubation, complications during thoracic or anterior neck surgery, botulinum toxin injection), with paralysis of the vocal cords.
• The subglottic / tracheal region can be obstructed by subglottic stenosis.
• In addition, foreign bodies, tumors, polyps, inhalation injuries, and traumatic injuries can affect any of these regions.

Upper airway obstruction characteristically presents with stridor. Signs of more severe airway obstruction include respiratory distress, tachypnea, use of accessory muscles of respiration, and agitation. Severe upper airway obstruction can cause abnormalities of blood gases, including hypoxemia, which can lead to cardiac arrest.

Treatment is dependent on the underlying etiology; however, intubation may be required in severe cases regardless of the cause.