Wenzel RP, Fowler AA 3rd. Clinical practice. Acute Bronchitis. N Engl J Med 2006;355:2125-2130: This article on the topic of bronchitis is one of the clinical practice reviews from The New England Journal of Medicine. The following are highlights:
Definition: Self-limited inflammation of the large airways of the lung clinically expressed as cough without pneumonia.
Frequency: 5% in adults/year.
Natural history: There is usually an upper respiratory tract infection (URI), and 'acute bronchitis' is characterized by coughing that persists more than 5 days that is accompanied by abnormal pulmonary function. Approximately 40% of cases have reductions in forced expiratory volume (FEV) or bronchial hyperactivity with improvement at follow-up at 5-6 weeks. Cough usually lasts 10-20 days, but occasionally longer. About 50% of patients produce purulent sputum that represents sloughed tracheobronchial epithelium and inflammatory cells.
Diagnostic testing: The presence of normal vital signs and absence of rales suggest that additional diagnostic testing is usually unnecessary. The exception is elderly patients 75 years of age or older who may have pneumonia in the absence of fever or tachycardia. The presence of rales, abnormal vital signs, or acute cough in elderly patients is generally regarded as an indication for a chest radiograph. A rapid diagnostic test to identify a specific pathogen is recommended when the suspected pathogen is treatable, the pathogen is in the community, and the patient has compatible symptoms. This generally means influenza. Polymerase chain reaction (PCR) testing of nasopharyngeal swabs or aspirates are being developed for detection of Bordetella pertussis, Mycoplasma pneumoniae, and Chlamydophila pneumoniae for multiplex testing.
Etiology: Most cases are caused by viral infections, but the cause is rarely determined. Some of the major pathogens are summarized in the Table .
Treatment: A Cochrane Review of 9 randomized, controlled trials of antibiotics showed significant benefit in terms of duration of cough, but the benefit was trivial (reduction by a mean of 0.6 days) and there was an increase in adverse reactions that was not statistically significant. Oseltamavir and zanamivir for influenza reduced the duration of symptoms by approximately 1 day and reduced the time to resume normal activity by 0.5 days when given within the first 48 hours of symptoms. Macrolide treatment of pertussis may reduce transmission, but does not improve symptoms unless initiated within the first week of symptoms. It is unclear if there is therapeutic benefit for treating acute bronchitis involving M pneumoniae or C pneumoniae.
Other therapy: Use of beta-2 agonists by mouth or aerosol have shown mixed results in trials.[7,8,9] A Cochrane Review concluded that the benefit of these drugs, primarily albuterol, is not well supported even in patients with airflow obstruction. The authors suggest a 7-day trial of inhaled or oral corticosteroids for a 'troublesome cough' that persists more than 20 days, but there are not good clinical trial data to support this. There are no clinical trials to support use of mucolytic or antitussive agents.
Guidelines: The 2001 guidelines from the American College of Physicians recommend against the use of antibiotics. The 2006 guidelines from the American College of Chest Physicians recommend against antibiotics, note that antitussive agents are 'only occasionally useful' and that there is no role for inhaled bronchodilators or mucolytic agents. Nevertheless, both guidelines note that there are subgroups of patients with chronic airflow obstruction or wheezing that would benefit from beta-2 agonists. Both guidelines have been criticized as based 'more on opinion than on evidence.'
Medscape Infectious Diseases © 2007 Medscape
Cite this: Acute Bronchitis Literature: Commentary by Dr. John G. Bartlett -- April 2007 - Medscape - May 01, 2007.