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Endobronchial lesions are caused by a variety of benign and malignant disease processes. When such lesions obstruct the central airways, trachea, or mainstem bronchi, they quickly turn life threatening. The incidence of central airway obstruction (CAO) has increased largely because of the prevalence of lung cancer. It causes significant morbidity and, without treatment, may lead to suffocation and death. This chapter reviews the gamut of available endobronchial techniques for managing acute CAO, including endobronchial resection with electrocautery, argon plasma coagulation, laser therapy, photodynamic therapy, cryotherapy, external beam radiation and brachytherapy, and airway stents. The most comprehensive use of these techniques should be offered at centers experienced in the management of complex airway disorders with the full array of endoscopic and surgical options at their disposal.
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Etiology/Natural History of Disease
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CAO causes significant morbidity and mortality in patients with malignancies that affect the upper airways. Although the precise incidence and prevalence of CAO are unknown, current lung cancer rates suggest that an increasing number of patients experience complications of proximal endobronchial disease.1 It has been estimated that approximately 20% to 30% of patients with lung cancer develop complications associated with airway obstruction (i.e., atelectasis, pneumonia, or dyspnea)2 and that up to 40% of lung cancer deaths are caused by locoregional disease.3 With increased use of temporary artificial airways, such as endotracheal intubation, in a growing elderly population, the incidence of CAO from malignant, nonmalignant, or iatrogenic complications is also predicted to rise.
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The most frequent cause of malignant CAO is by direct invasion of an adjacent tumor, chiefly bronchogenic carcinoma, secondarily esophageal and thyroid carcinoma. Primary tumors of the central airway are relatively uncommon. Most primary tracheal tumors are squamous cell carcinoma or adenoid cystic carcinoma. Distal to the carina, the carcinoid tumors account for the majority of primary airway tumors.4 Distant tumors, such as renal cell, breast, and thyroid, also may metastasize to the airway. Although the epidemiologic data are limited, the most commonly encountered nonmalignant causes of CAO are stenosis from the proliferation of granulation tissue resulting from prior endotracheal or tracheostomy tubes, airway foreign bodies, and tracheo- or bronchomalacia.5
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Presenting Signs and Symptoms
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The clinical presentation of patients with CAO secondary to endobronchial lesions depends not only on the underlying disease but also on the location and rate of progression of the airway obstruction, the patient's underlying health status, and other associated symptoms, such as postobstructive sequelae. Mild airway obstructions may have only slight effect on airflow; hence, the patient may be asymptomatic. However, the inflammation associated with even mild respiratory tract infections can cause mucosal swelling and mucous production, which may further occlude the lumen. For this reason, patients sometimes are misdiagnosed with exacerbations of chronic obstructive pulmonary disease or asthma, especially when symptoms such as wheezing and dyspnea improve with therapy aimed at treating the superimposed ...