If clinical presentation suggests impending airway obstruction, lab work does little to inform immediate decision making, and the increased stress may convert a partial obstruction into a critical airway Oxygenation may be determined noninvasively by pulse oximetry Suspicion for traumatic injury warrants cervical spine immobilization Definitive airway control prior to full evaluation may be necessary Child With Neck Mass and Respiratory Distress or Systemic Toxicity The mechanism and duration of symptoms are crucial elements in the evaluation of a neck mass Trauma from vehicular collisions, falls from heights, or sports injuries may cause formation of a hematoma near vital structures such as the carotid artery or trachea (see Chapter 112 Neck Trauma ) Allergic reactions ranging from local bee stings to anaphylaxis may precipitate an acute emergency if there is enough tissue edema to obstruct the larynx or trachea (see Chapter 85 Allergic Emergencies ) Local and regional infections may present with cervical lymphadenopathy, but can have more significant life-threatening aspects Acute airway obstruction may result from viral or bacterial infections with associated tonsillar hypertrophy or laryngocele enlargement Bacterial pharyngitis occasionally progresses to deep space neck infections including retropharyngeal abscess, lateral pharyngeal abscess (LPA), and peritonsillar abscess (PTA) Lemierre syndrome, an uncommon parapharyngeal infection involving thrombophlebitis of the internal jugular vein with septic emboli including metastatic pulmonary abscesses, may manifest as respiratory distress and systemic toxicity in the adolescent with a history of pharyngitis Dental infection that spreads to the floor of the mouth (i.e., Ludwig angina) and neck may cause cervical swelling and airway compression Rarely, epiglottitis may present with associated cervical adenitis or the appearance of a submandibular mass from ballooning of the hypopharynx Concomitant dysphagia, drooling, or stridor would raise suspicion for these complications Occasionally, branchial cleft cysts or cystic hygromas can become infected and progress to abscess formation or rarely to mediastinitis Children with human immunodeficiency virus (HIV) infection (see Chapter 94 Infectious Disease Emergencies ) may present with parotitis or generalized lymphadenopathy (e.g., axillary, cervical, occipital), particularly visible in the neck Children may have hyperthyroid symptoms when a neck mass represents thyromegaly Similarly, patients with the mucocutaneous lymph node syndrome