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Source: Blackford MG, Glover ML, Reed MD. Lower Respiratory Tract Infections. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th edition. Accessed July 12, 2012.

  • Inflammatory condition of large elements of tracheobronchial tree usually associated with generalized respiratory infection. Inflammatory process does not include alveoli.

  • Most commonly occurs during winter months
  • Attacks precipitated by:
    • Cold, damp climates
    • Presence of high concentrations of irritating substances
      • Air pollution
      • Cigarette smoke
  • Most commonly caused by respiratory viruses such as rhinovirus and coronavirus.
  • Bacterial causes include Mycoplasma pneumoniae.

  • Occurs in all ages.
  • Infection of trachea and bronchi causes:
    • Hyperemic and edematous mucous membranes
    • Increase in bronchial secretions
      • Impairs mucociliary activity.

  • Recurrent acute respiratory infections may be associated with increased airway hyperreactivity and possibly pathogenesis of chronic obstructive lung disease.

  • Cold, damp climate
  • Air pollution
  • Cigarette smoke

  • Usually begins as upper respiratory infection.

Signs and Symptoms

  • Cough is hallmark symptom.
    • Initially nonproductive but progresses to mucopurulent sputum.
    • Persists up to 3 weeks despite resolution of nasal or nasopharyngeal complaints.
  • Nonspecific complaints, such as malaise and headache, coryza, and sore throat
  • Chest examination: rhonchi and coarse, bilateral, moist rales
  • Mild to moderate wheezing

Means of Confirmation and Diagnosis

  • History and physical examination

Laboratory Tests

  • Sputum cultures of limited utility


  • Chest radiographs usually normal

Differential Diagnosis

  • Provide comfort to patient.
  • Avoid dehydration and respiratory compromise in severe cases.

  • Treatment symptomatic and supportive in nature.

  • Bedrest
  • Analgesics
  • Antipyretics
  • Fluids

  • Routine use of antibiotics in treatment of acute bronchitis discouraged.
    • If fever or respiratory symptoms persist for >4–6 days, consider possibility of concurrent bacterial infection.
      • Direct antibiotic therapy toward anticipated respiratory pathogen(s).

  • Patients should contact physician if symptoms do not resolve within 4–6 days.

  • Primarily self-limiting illness and rarely cause of death.

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