Harvey's Garden

Acute bronchitis

2 min read

  • Epidemiology & Risk Factors

    • 90% viral etiology (Rhinovirus, Coronavirus, Influenza, RSV, Parainfluenza).

    • Bacterial causes are rare (<10%) and include Bordetella pertussis, Mycoplasma pneumoniae, Chlamydia pneumoniae.
    • Often preceded by a standard viral URI.

  • Clinical Features

    • Hallmark: Cough persisting > 5 days (typically lasts 1-3 weeks).
    • Sputum production (clear, yellow, or green/purulent – purulence is due to sloughed epithelial cells, NOT necessarily bacterial infection).
    • Wheezing or rhonchi that clear with coughing.
    • Mild dyspnea.
    • Negative findings: Usually lacks high fever, tachycardia, tachypnea, or focal lung examination findings (e.g., crackles, egophony).

  • Diagnosis

    • Initial/Screening: Primarily a clinical diagnosis.
    • Key Labs/Imaging:
      • CXR: Usually normal. Indicated only if pneumonia is suspected to rule out consolidation. Criteria for CXR: Abnormal vital signs (HR >100, RR >24, Temp >38°C/100.4°F) or focal consolidation signs on exam (rales, egophony, tactile fremitus).
      • Respiratory viral panel (e.g., Influenza/COVID-19 swab) if in season and will change management.
    • Confirmatory/Gold Standard: Clinical diagnosis; no routine confirmatory testing required.

  • Differential Diagnostics

    • Pneumonia: Diff by (+) high fever, focal crackles/rales, signs of consolidation (dullness to percussion, (+) egophony), and infiltrates on CXR.
    • Asthma Exacerbation: Diff by hx of recurrent wheezing/atopy, reversible airflow obstruction on spirometry.
    • Pertussis: Diff by paroxysmal cough, inspiratory “whoop,” post-tussive emesis, lack of routine vaccinations.
    • Post-Nasal Drip / GERD / ACE-I Cough: Diff by chronic cough (>8 weeks) and lacking preceding acute URI symptoms.

  • Management

    1. First-line (Supportive): Symptom relief.
      • NSAIDs/Acetaminophen for malaise.
      • Antitussives (e.g., dextromethorphan, guaifenesin) for cough suppression (limited efficacy but commonly used).
    2. Targeted Symptom Relief: Inhaled bronchodilators (albuterol) only if active wheezing/underlying bronchospasm is present.
    3. Antibiotics are NOT indicated: High-yield NBME concept. Do not prescribe Abx even if sputum is purulent/green, unless B. pertussis is confirmed or strongly suspected (then macrolides).

  • Complications

    • Post-viral cough (hyperreactive airways persisting weeks to months).
    • Bronchospasm.
    • Rare progression to secondary bacterial pneumonia.

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