Acute bronchitis (or tracheobronchitis) and community-acquired pneumonia are two prevalent disorders in the general population. In this chapter we discuss important clinical aspects of these infections, including diagnostic approaches and treatment strategies.
Acute bronchitis is inflammation of the large airways without evidence of pneumonia. Approximately 5% of adults develop acute bronchitis in a given year, resulting in approximately 100 million ambulatory care visits in the United States.1 Consumers in the United States spend roughly $7 billion annually on the management of cough—the most common symptom of acute bronchitis.2
Respiratory viruses, including rhinovirus, coronavirus, parainfluenza virus, respiratory syncytial virus, human metapneumovirus, and influenza virus, are responsible for up to 90% of cases (although many patients with acute bronchitis do not have a specific pathogen identified).1,3 The important role of respiratory viruses in disease pathogenesis helps explain the increased incidence of acute bronchitis in the fall and winter. Bordetella pertussis, Mycoplasma pneumoniae, and Chlamydia pneumoniae are the bacteria most frequently identified in immunocompetent adults with acute uncomplicated bronchitis in the absence of chronic lung disease.4 Moraxella catarrhalis, Haemophilus influenzae, and Streptococcus pneumoniae are more common in patients with chronic obstructive pulmonary disease (COPD) and possibly in smokers without overt COPD.
Cough, with or without sputum production, is the hallmark of acute bronchitis. Although patients with purulent sputum are more frequently prescribed antibiotic therapy, sputum appearance is an unreliable surrogate for bacterial infection and does not identify patients more likely to benefit from antibiotics.4,5 On average, cough lasts for 10 to 20 days but can persist for more than a month.6 Patients may also endorse headaches, rhinorrhea, and mild constitutional symptoms.
Given the self-limited nature of acute bronchitis, the goal of a clinical evaluation is to exclude potentially life-threatening diagnoses whose symptoms may overlap with acute bronchitis, including pneumonia and exacerbations of asthma, COPD, and congestive heart failure (CHF). In younger patients without comorbidities, a persistent cough coupled with normal vital signs and a reassuring physical examination is sufficient to diagnose acute bronchitis.7 For elderly patients and those with chronic health conditions, basic laboratory testing and a chest radiograph are often required to exclude more concerning diagnoses.
Although a large number of both over-the-counter and prescription pharmacotherapies are available for the symptomatic management of acute bronchitis, evidence to support the efficacy of any specific medication is minimal.8,9 Guidelines do not recommend the routine prescription of antitussives, inhaled bronchodilators, oral corticosteroids, or other oral anti-inflammatory medications.7 Management is, therefore, supportive, and plans should be made for clinical re-evaluation if a patient experiences persistent or progressive symptoms. The development of “red flag” symptoms including hemoptysis, worsening dyspnea, weight loss, difficulty swallowing, and persistent fever should trigger a more urgent evaluation.10