- • Obstruction may be caused by structural/anatomic
abnormalities (tumors, foreign bodies, infections) or functional
abnormalities (vocal cord dysfunction, muscle tension dysphonia).
- • Symptoms include cough, stridor, shortness of breath,
globus sensation, hoarseness.
- • Pulmonary function testing including flow volume
loops showing truncation.
- • Laryngoscopy reveals cause of mechanical or anatomical
- • Bronchoscopy may be necessary if obstruction occurs
in the subglottic large airway including trachea and main bronchi.
In this chapter the large airways will be considered to include
the pharynx, larynx, trachea, and main bronchi. Obstruction of the
large airways should be considered when patients present with symptoms
and signs of obstructive airways disease but do not have findings
consistent with asthma or chronic obstructive lung disease or have
these conditions but demonstrate a pronounced worsening of symptoms
not controlled with standard medication. In the young age groups,
foreign bodies and congenital webs are the most common abnormalities;
whereas in the elderly population, tumors both benign and malignant
and laryngeal manifestations of systemic diseases such as sarcoidosis
or collagen vascular diseases are of greatest concern.
There are both acute and chronic causes of upper airway obstruction.
Acute causes include aspiration of a foreign body as well as causes
associated with direct blunt trauma such as fractures of the laryngeal
cartilages, arytenoid cartilage dislocation, hematoma formation,
and bilateral vocal cord paralysis. These injuries may be overlooked
if the patient is intubated following massive trauma (eg, trauma
resulting from motor vehicle accidents or falls). Only after the
patient is extubated may such injuries be appreciated. The physician
should be alert to evaluating these patients by laryngoscopy during
intubation and soon after extubation. Intubation and various invasive
surgical and medical procedures of the head and neck area lead to
vocal cord paralysis and/or obstruction due to hematoma
or formation of infectious abscess. There are a variety of drugs
that lead to upper airway obstruction including the sedative hypnotics
such as benzodiazepines that produce somnolence, respiratory depression,
reduction in upper airway muscle tone, reduced cough response, and
a blunted respiratory drive to hypoxia and hypercarbia. Use of the
anticoagulants warfarin and heparin may put patients at risk for
formation of hematoma secondary to relatively minor trauma.
Large airway obstruction caused by bacterial infection is seen
in children and is less common in adults. Noniatrogenic infections
including tracheitis and supraglottitis are commonly due to Staphylococcus aureus and Streptococcus species. Adult croup
may be due to viral rather than bacterial sources. Retropharyngeal
abscesses and dental, sublingual, submandibular, and other oral
cavity infections are commonly due to Streptococcus or
oral anaerobic species. Miscellaneous causes for acute upper airway
obstruction include thermal injuries, systemic anaphylaxis, and
rapid thyroid enlargement such as during pregnancy or postradiation
Chronic or slowly progressive causes of airflow obstruction include
vocal cord polyps or granulomas and tumors of the aerodigestive
tract, particularly invasive malignancies such as squamous cell
carcinomas, lymphomas, or thyroid cancers. Children, in ...