Acute bronchitis is a commonly encountered, self-limited, infection producing inflammatory changes within the larger airways. Sharing the viral pathogens of upper respiratory infections, including those of the common cold, acute bronchitis is often caused by one of the following: influenza A or B virus, adenovirus, rhinovirus, parainfluenza virus, respiratory syncytial virus, or coronavirus. Far less frequent in etiology, the bacterial pathogens Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Bordatella pertussis may lead to more severe presentations in older populations, especially in those with increased comorbidities.
The predominant cough of acute bronchitis may be productive and can easily last up to 3 weeks. Sputum purulence is usually indicative of sloughed inflammatory airway cells and, taken alone, does not indicate a bacterial etiology. Bronchitis most commonly lacks the suggestive symptoms and signs of pneumonia, specifically fever >38°C (100.4°F), adult heart rate >100 beats/min, and/or adult respiratory rate >24 breaths/min. Wheezing may be present.
Diagnosis and Differential
The diagnosis of acute bronchitis can be made clinically with the following criteria: (a) acute-onset cough (shorter than 3 weeks duration), (b) absence of chronic lung disease history, (c) normal vital signs, and (d) absence of auscultatory abnormalities that suggest pneumonia. Pulse oximetry is indicated if the patient describes dyspnea or appears short of breath. Bedside peak flow testing may reveal reductions in forced expiratory volume in 1 second. A chest radiograph is not required in non-elderly patients who appear nontoxic. Consider pertussis in adolescents and young adults whose coughs persist beyond 2 to 3 weeks, particularly if they exhibit coughing paroxysms with prominent post-tussive emesis or had exposure to pertussis.
Emergency Department Care and Disposition
The use of antibiotics for acute bronchitis, while commonly requested by patients and prescribed by practitioners, does NOT confer clinically relevant benefits in a viral illness, but produces side effects such as gastrointestinal distress, vaginitis, and future pathogen resistance.
If pertussis is strongly suspected, prescribe azithromycin 500 mg orally on day 1, followed by 250 mg orally on days 2 to 5. This treatment does not shorten the illness, but decreases coughing paroxysms and limits disease transmission.
Patients with evidence of airflow obstruction who are treated with bronchodilators experience faster cough resolution. Albuterol two puffs every 4 to 6 hours using a metered dose inhaler and spacer provides symptomatic relief in dyspnea and cough.
Consider additional agents for cough suppression, mucolysis, and other symptomatic relief on an individual basis factoring comorbidities, drug interactions, and potential side effects.
Discharge patients with instructions for timely follow-up with a primary care physician, smoking cessation when applicable, and when to return to the emergency department based upon clinical symptoms.
Pneumonia is most commonly a bacterial infection of the alveolar lung. Pneumococcus (Streptococcus pneumoniae) is the classic bacterial ...