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Emergency and Acute Medicine – Acute Bronchitis
Overview And Definitions
Acute bronchitis is an inflammatory condition of the bronchial airways characterized by mucosal hyperemia, edema, and excess mucus production. Impairment of ciliary function and local immune defenses leads to airway obstruction caused by edema, secretions, and bronchial smooth muscle spasm. The condition is usually self-limited and most often follows an upper respiratory tract infection.
Etiology And Pathophysiology
Acute bronchitis is predominantly viral in origin. Common pathogens include parainfluenza, influenza A and B, respiratory syncytial virus, human metapneumovirus, adenovirus, coronavirus, rhinovirus, echovirus, coxsackievirus, and, less commonly, measles and herpes viruses, which may cause severe disease. Certain organisms are associated with more prolonged or severe illness, including Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis. Pertussis incidence is increasing even among immunized individuals due to waning immunity. Bacterial causes are otherwise uncommon except in patients with chronic lung disease.
Clinical Presentation
Patients often describe a prodrome of malaise, chills, myalgias, coryza, and sore throat, followed by cough that is initially dry and later becomes mucoid or mucopurulent. Mild dyspnea and chest discomfort or burning related to coughing are common. Symptoms typically improve after 3–5 days, though cough and fatigue may persist for 1–3 weeks. Physical examination may reveal low-grade fever, tachypnea, rhonchi or wheezing, and occasional crackles. Mild hemoptysis can occur.
Diagnostic Evaluation
Diagnosis is primarily clinical. Routine laboratory testing is generally unnecessary. Influenza A and B testing may be useful when results would alter management or reporting. Pertussis should be considered in patients with cough lasting 14 days or longer, especially with paroxysms, post-tussive vomiting, inspiratory whoop, or known outbreak exposure. Chest radiography is not routinely indicated but should be obtained in patients with hypoxia, dyspnea, chest pain, tachycardia, tachypnea, fever ≥38°C, focal lung findings, advanced age, or significant comorbid disease. Imaging typically shows no consolidation in uncomplicated bronchitis.
Differential Diagnosis
Important alternatives include pneumonia, reactive airway disease or asthma, aspiration, acute sinusitis, and, in chronic cases, gastroesophageal reflux disease, chronic bronchitis, bronchiectasis, ACE inhibitor–related cough, malignancy, heart failure, sarcoidosis, and psychogenic cough.
Management And Emergency Care
Treatment is supportive. Oxygen is administered for hypoxia, and fluids are given if dehydration is present. Bronchodilators may benefit patients with wheezing or evidence of airflow obstruction. Antitussives and antipyretics can be used for symptomatic relief. Antiviral therapy such as oseltamivir or zanamivir may be considered for early influenza-related illness, and amantadine may be used selectively during influenza A outbreaks, accounting for resistance patterns. Antibiotics are generally not recommended, even with purulent sputum, due to minimal benefit and risks of resistance and adverse effects. They may be considered if fever recurs after initial improvement or if pertussis is confirmed. Smoking cessation should be encouraged but does not alone justify antibiotic use.
Disposition And Follow-Up
Most patients can be safely discharged if there is no significant respiratory compromise. Admission is reserved for those with hypoxia, significant cardiopulmonary disease, severe illness, or diagnostic uncertainty. Patients should be advised that cough may persist for several weeks and instructed to return for worsening symptoms, new dyspnea, or lack of improvement after 2–3 weeks. Routine follow-up is unnecessary if symptoms resolve.
Key Clinical Insights And Common Errors
High fever, hypoxia, or focal pulmonary findings should prompt evaluation for pneumonia. Acute bronchitis is most often viral, and unnecessary antibiotic use is a frequent error. Immunocompromised patients may develop more severe disease and warrant closer monitoring and coordination with their primary physician.
Overview And Definitions
Acute bronchitis is an inflammatory condition of the bronchial airways characterized by mucosal hyperemia, edema, and excess mucus production. Impairment of ciliary function and local immune defenses leads to airway obstruction caused by edema, secretions, and bronchial smooth muscle spasm. The condition is usually self-limited and most often follows an upper respiratory tract infection.
Etiology And Pathophysiology
Acute bronchitis is predominantly viral in origin. Common pathogens include parainfluenza, influenza A and B, respiratory syncytial virus, human metapneumovirus, adenovirus, coronavirus, rhinovirus, echovirus, coxsackievirus, and, less commonly, measles and herpes viruses, which may cause severe disease. Certain organisms are associated with more prolonged or severe illness, including Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis. Pertussis incidence is increasing even among immunized individuals due to waning immunity. Bacterial causes are otherwise uncommon except in patients with chronic lung disease.
Clinical Presentation
Patients often describe a prodrome of malaise, chills, myalgias, coryza, and sore throat, followed by cough that is initially dry and later becomes mucoid or mucopurulent. Mild dyspnea and chest discomfort or burning related to coughing are common. Symptoms typically improve after 3–5 days, though cough and fatigue may persist for 1–3 weeks. Physical examination may reveal low-grade fever, tachypnea, rhonchi or wheezing, and occasional crackles. Mild hemoptysis can occur.
Diagnostic Evaluation
Diagnosis is primarily clinical. Routine laboratory testing is generally unnecessary. Influenza A and B testing may be useful when results would alter management or reporting. Pertussis should be considered in patients with cough lasting 14 days or longer, especially with paroxysms, post-tussive vomiting, inspiratory whoop, or known outbreak exposure. Chest radiography is not routinely indicated but should be obtained in patients with hypoxia, dyspnea, chest pain, tachycardia, tachypnea, fever ≥38°C, focal lung findings, advanced age, or significant comorbid disease. Imaging typically shows no consolidation in uncomplicated bronchitis.
Differential Diagnosis
Important alternatives include pneumonia, reactive airway disease or asthma, aspiration, acute sinusitis, and, in chronic cases, gastroesophageal reflux disease, chronic bronchitis, bronchiectasis, ACE inhibitor–related cough, malignancy, heart failure, sarcoidosis, and psychogenic cough.
Management And Emergency Care
Treatment is supportive. Oxygen is administered for hypoxia, and fluids are given if dehydration is present. Bronchodilators may benefit patients with wheezing or evidence of airflow obstruction. Antitussives and antipyretics can be used for symptomatic relief. Antiviral therapy such as oseltamivir or zanamivir may be considered for early influenza-related illness, and amantadine may be used selectively during influenza A outbreaks, accounting for resistance patterns. Antibiotics are generally not recommended, even with purulent sputum, due to minimal benefit and risks of resistance and adverse effects. They may be considered if fever recurs after initial improvement or if pertussis is confirmed. Smoking cessation should be encouraged but does not alone justify antibiotic use.
Disposition And Follow-Up
Most patients can be safely discharged if there is no significant respiratory compromise. Admission is reserved for those with hypoxia, significant cardiopulmonary disease, severe illness, or diagnostic uncertainty. Patients should be advised that cough may persist for several weeks and instructed to return for worsening symptoms, new dyspnea, or lack of improvement after 2–3 weeks. Routine follow-up is unnecessary if symptoms resolve.
Key Clinical Insights And Common Errors
High fever, hypoxia, or focal pulmonary findings should prompt evaluation for pneumonia. Acute bronchitis is most often viral, and unnecessary antibiotic use is a frequent error. Immunocompromised patients may develop more severe disease and warrant closer monitoring and coordination with their primary physician.
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