Etiology and Epidemiology
Bronchiectasis is an irreversible airway dilation that involves the lung in either a focal (due to obstruction) or a diffuse (due to a systemic or infectious process) manner. Bronchiectasis can arise from infectious or noninfectious causes.
• The epidemiology varies greatly with the underlying etiology; in general, the incidence of bronchiectasis increases with age and is higher among women than among men.
• 25–50% of pts with bronchiectasis have idiopathic disease.
Pathogenesis
The most widely cited mechanism of infectious bronchiectasis is the “vicious cycle hypothesis,” in which susceptibility to infection and poor mucociliary clearance result in microbial colonization of the bronchial tree. Proposed mechanisms for noninfectious bronchiectasis include immunemediated reactions that damage the bronchial wall and parenchymal distortion as a result of lung fibrosis (e.g., postradiation fibrosis or idiopathic pulmonary fibrosis).
Clinical Manifestations
Presenting pts typically have a persistent productive cough with ongoing production of thick, tenacious sputum.
• Physical exam usually reveals crackles and wheezing on lung auscultation and occasionally reveals digital clubbing.
• Acute exacerbations are associated with increased purulent-sputum production.
Diagnosis
The diagnosis of bronchiectasis is based on clinical presentation with consistent radiographic findings, such as parallel “tram tracks,” a “signet-ring sign” (a cross-sectional area of the airway with a diameter at least 1.5 times that of the adjacent vessel), lack of bronchial tapering, bronchial wall thickening, or cysts emanating from the bronchial wall.
TREATMENT
Treatment of infectious bronchiectasis is directed at the control of active infection and at improvements in secretion clearance and bronchial hygiene.
• Acute exacerbations should be treated with a 7- to 10-day course of antibiotics targeting the causative or presumptive pathogen; H. influenzae and P. aeruginosa are isolated commonly.
• Hydration and mucolytic administration, aerosolization of bronchodilators and hyperosmolar agents (e.g., hypertonic saline), and chest physiotherapy can be used to enhance secretion clearance.
• For pts with ≥3 recurrences per year, suppressive antibiotic treatment to minimize the microbial load and reduce the frequency of exacerbations has been proposed.
• In select cases, surgery (including lung transplantation) should be considered.
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