Pulmonary infections in children with cystic fibrosis.

Bronchopulmonary infections continue to be the major determinant of morbidity and mortality in patients with cystic fibrosis (CF). The basic pathogenesis of disease includes abnormal secretions and impaired mucociliary clearance. Colonization of the tracheobronchial tract with bacteria is then associated with a cycle of infection, inflammation and airway obstruction eventually leading to respiratory insufficiency. Early clinical features include persistent cough and failure to thrive. Hyperinflation and bronchial thickening are early radiographic changes suggestive of CF. Staphylococcus aureus is commonly the initial respiratory pathogen. Subsequently, Hemophilus influenzae and Pseudomonas aeruginosa colonize the respiratory tract. In addition, respiratory viruses and other pathogens such as Legionella and mycoplasma are implicated in the etiology of pulmonary infections. The culture of respiratory secretions such as sputum are important guidelines to the etiology of pulmonary infection in CF. The laboratory must be aware of the pathogens that are typical of this disease and use appropriate techniques and media. In large part, advances in treatment in CF over the past two decades are due to the availability of increasingly potent antibiotic agents. However, effective treatment must be multifaceted and include a variety of nonantimicrobial therapies. Different approaches to the antibiotic therapy of pulmonary infection in CF, including prevention, suppression, and definitive treatment are discussed. In addition to traditional antibiotic therapy, a variety of newer methods of therapy in CF are discussed. These include oral antipseudomonal antibiotics, corticosteroid therapy, aerosolized antibiotics, and continuous antimicrobial prophylaxis.