Bronchiectasis is a considerable cause of respiratory illness (Fig. 83-1). It is defined by the permanent dilatation of the bronchi1 and caused by a recurrent process of transmural infection and inflammation. Repeated pulmonary infections, a progressive decline in respiratory function despite prolonged antibiotic treatment, and occasional life-threatening hemoptysis are typical once the disease is entrenched. Patients with either focal or diffuse patterns of bronchiectasis may be eligible for surgical intervention; the diffuse form of the disease is best treated with bilateral lung transplantation and will not be discussed extensively in this chapter.
The three basic forms of bronchiectasis are depicted. Cylindrical or tubular bronchiectasis gives rise to tapered airways. Varicose bronchiectasis is characterized by areas of dilatation and narrowing. Saccular or cystic bronchiectasis causes progressively dilated airways that end in saclike cystic structures that resemble clusters of grapes.
The disease process is characterized by the pathologic or radiographic appearance of the airways. Cylindrical or tubular bronchiectasis results in dilated, slightly tapered airways. Varicose bronchiectasis (Fig. 83-2) resembles the chronic venous state of the same name, with areas of dilatation and narrowing. Saccular or cystic bronchiectasis is characterized by progressive dilatation of the airways that can end in saclike cystic structures that resemble a cluster of grapes (Fig. 83-3). The cylindrical narrowing is often seen with tuberculosis infections, whereas the saccular or cystic type is more common after obstruction or bacterial infection. Thick mucoid secretions are often seen pooled in the dilated airways and cause a chronic inflammatory state involving the airway walls. The lung parenchyma distal to the dilated, ectatic airways is often damaged as well, with fibrosis and emphysematous changes present. The accompanying bronchial arteries and lymph nodes also may be engorged and hypertrophied. The usual area of involvement is the left lower lobe, followed by the lingula and right middle lobe.
CT appearance of varicose bronchiectasis.
CT appearance of saccular or cystic bronchiectasis. Note the saclike cystic structures that resemble a cluster of grapes.
A number of congenital and acquired diseases lead to the development of bronchiectasis. The common pathway for each of these disorders is recurrent transmural infection of the bronchial wall. Bacterial infections, particularly those involving potentially necrotizing agents such as Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae, and various anaerobes, remain important causes of bronchiectasis, particularly when there is a delay in treatment or other factors that prevent eradication of the infection. Bronchiectasis in patients with allergic bronchopulmonary aspergillosis is caused by an immune reaction to the fungal organ, with production of inflammatory mediators and subsequent direct airway invasion by the fungus. Viral infections can lead ...