Lindsay Lipinski and David Goldenberg

Functionally, the airway begins at the nares and mouth and continues into the thoracic cavity to the bronchioles. Along this passageway, therefore, there are several anatomical locations that can cause obstruction. The airway can be divided into extrathoracic (including supralaryngeal, supraglottic, glottic, and subglottic areas) and intrathoracic (the tracheobronchial tree). The location of the obstruction can often be determined by carefully noting the qualities of the sounds made by the obstructed patient during breathing. The site of obstruction also plays an important role in treatment. Thus the diagnostic approach detailed following here is based on airway anatomy.

The age of the patient may help in determining the diagnosis. Pediatric airway obstruction tends to be due to a congenital or inflammatory condition; in adults, obstruction is usually caused by a neoplasm or an inflammatory condition. In adults, airways are wider and can tolerate greater degrees of obstruction. Children, whose airways are much narrower, will become symptomatic more quickly. The glottis is the narrowest part of the adult airway, whereas the subglottis is narrowest in children, and even a minor degree of inflammation in this area can cause severe distress.

A thorough clinical history and a complete physical examination are major components in reaching the diagnosis. The onset, frequency, and duration of symptoms should be determined, as well as any associations (feeding position changes, exercise, sleep). Obstruction may also be classified by whether it is local or systemic, and associated symptoms (such as dysphagia, drooling, aspiration, cough, bleeding) may help to determine this. A history of previous surgery, intubation, tracheotomy, or trauma can help to localize the problem. For pediatric patients, a birth and developmental history should be obtained. Physical exam, including indirect laryngoscopy, will provide further information. In some cases, additional diagnostic testing, including radiography, pulmonary function testing, and airway visualization, may be necessary.

Supralaryngeal (Associated Sounds: Stridor, Gurgling)

Congenital: Defects in the complex formation and development of the oral cavity, nasal cavity, and pharynx can lead to a variety of malformations that can cause obstructive symptoms.

Micrognathia: This defect in the formation of the jaw is due to retarded growth of the mandible, causing the tongue to be relatively large for the oral cavity.

Choanal atresia: Caused by obliteration or blockage of the posterior nasal aperture, this malformation is often associated with bony abnormalities of the pterygoid plates and midfacial growth abnormalities.

Lingual thyroid: Ectopic tissue may be present at the foramen cecum, and this can be confirmed by radionuclide scanning.

Nasal septal deformity: This malformation is due to intrauterine pressure effects or intrapartum trauma, or occurs in association with other anomalies.

Pyriform aperture stenosis: Congenital stenosis of this opening due to bony overgrowth can cause airway obstruction in infants.

Infectious: Several infectious processes should be considered in the supralaryngeal airway, especially in febrile or toxic patients.

Retropharyngeal/peritonsillar abscess: A complication of acute tonsillitis, abscesses are associated with trismus, severe sore throat, malaise, and dehydration.

Mononucleosis: This viral infection is characterized by a triad of fever, tonsillar pharyngitis, and lymphadenopathy; rarely, edema of the soft palate and tonsils may lead to airway occlusion.

Diphtheria: An acute infection with Corynebacterium diphtheriae, most commonly occurring in the tonsillopharyngeal region, can rarely lead to massive swelling of the tonsils and uvula and cause respiratory insufficiency.

Ludwig angina: An acute cellulitis resulting from infection in the oral cavity that progresses to the tissues of the neck; the patient is ill and toxic with indurated swelling of the submandibular and submental space.

Inflammatory: Inflammation of the upper airway is a common cause of airway obstruction in both children and adults, and inflammation of any part of the mucous membrane in the pharynx is readily transferred to other areas.

Allergic rhinitis: This process is characterized by episodic sneezing, nasal blockage, and nonpurulent rhinorrhea; edematous mucosa may impair airflow.

Angioedema: Extravasation of fluid into the interstitium in response to an inflammatory cascade (allergic, autoimmune, and drug-related etiologies) can lead to localized swelling of mucous membranes.

Trauma: A history of trauma is important to consider in patients with difficulty breathing because it provides an obvious mechanism for obstruction.

Hematoma: The mass effect of a retropharyngeal hematoma may compromise airway patency and should be considered in patients with a history of head trauma.

Facial fracture: Displaced fractures or posttraumatic swelling can impinge on the airway and prevent adequate airflow.

Neoplasm