Home | Business News | Browse by Publication | J | Journal of Respiratory Diseases

Nontuberculous mycobacteria are an increasingly common cause -- Bronchiectasis, part 1: Presentation and diagnosis.

Article Excerpt
Byline: MEETA PRASAD, MD and GREGORY TINO, MD

Abstract: Bronchiectasis is associated with a number of predisposing factors, including severe infections, cystic fibrosis (CF), and allergic bronchopulmonary aspergillosis (ABPA). Patients typically present with persistent or recurrent cough and sputum production. Auscultation of the lungs may reveal diffuse or focal rales and rhonchi, or it may reveal signs of airway obstruction, such as wheezing, prolonged expiratory phase, or a mid-inspiratory squeak. Chest radiographs may show "tram-tracks," which represent thickened bronchial walls, or cystic spaces. Distinguishing diffuse from focal bronchiectasis is an important aspect of the diagnostic evaluation. Patients who have diffuse bronchiectasis warrant additional testing to identify a primary cause, such as CF, immunodeficiency states, primary ciliary dyskinesia, or ABPA. In patients with focal bronchiectasis, bronchoscopy is often necessary to exclude endobronchial obstruction. (J Respir Dis. 2007;28(12):545-554)

Key Words: Bronchiectasis, Cystic fibrosis, Allergic bronchopulmonary aspergillosis

---

Bronchiectasis has been increasingly recognized as a cause of potentially devastating pulmonary disease. The prevalence is probably rising, and it is estimated that 110,000 persons in the United States are currently undergoing treatment for bronchiectasis that is not related to cystic fibrosis (CF); the consequent additional economic burden is estimated at $630 million annually.1

First described in 1819 by R. T. H. Laennec, bronchiectasis is now understood to be characterized clinically by symptoms of chronic respiratory illness and pathologically by irreversible bronchial dilatation. In part 1 of this article, we will review the causes, clinical presentation, and diagnosis of bronchiectasis. Part 2, which will appear in a coming issue of The Journal of Respiratory Diseases, will focus on treatment strategies.

PATHOPHYSIOLOGY

Regardless of the specific cause, bronchiectasis primarily develops as a result of inflammatory damage to the bronchi and bronchiolar walls caused by infection or by toxic injury that predisposes the patient to recurrent bacterial infections and further damage.2 The inflammation is predominantly mediated by neutrophils, and there is an overexpression of inflammatory cytokines and oxygen-derived free radicals.

Macroscopically, bronchiectasis is characterized by abnormally dilated airways extending distally to the pleura, dilated bronchial arteries, edematous and inflamed bronchial mucosa, mucous plugs, and numerous abscesses. Microscopically, the bronchial walls appear thickened and dilated with inflammatory infiltrate, the ciliated airway epithelium is replaced by squamous or columnar epithelium, mucous glands are hypertrophied, and extensive anastomoses form between the bronchial and pulmonary vessels. With end-stage bronchiectasis, the elastin layer is lost and bronchial muscle and cartilage are destroyed.3

The most widely used classification system for the pathological patterns of bronchiectasis...

View this article FREE - Now for a Limited Time, try Goliath Business News
Free for 3 Days!