Learning Center Articles



  • Acute infection of lung parenchyma
  • Associated with significant morbidity and mortality rates
  • Pneumonia and influenza are 8th leading cause of death in the U.S.


  • Likely to result when defense mechanisms become incompetent or overwhelmed
  • Decreased cough and epiglottal reflexes may allow aspiration
  • Mucociliary mechanism impaired
    • Pollution
    • Cigarette smoking
    • Upper respiratory infections
    • Tracheal intubation
    • Aging
  • Chronic diseases suppress immune system
  • Chronic diseases suppress immune system
  • Three ways organisms reach lungs:
    • Aspiration from nasopharynx or oropharynx
    • Inhalation of microbes present in air
    • Hematogenous spread from primary infection elsewhere in body

Types of Pneumonia

  • Can be classified according to causative organism
  • Clinical classification:
    • Community-acquired (CAP)
      • Occurs in patients who have not been hospitalized or resided in a long-term care facility within 14 days of the onset of symptoms
      • Can be treated at home or hospitalized dependent on patient condition
      • Empiric antibiotic therapy started ASAP
    • Hospital-acquired (HAP)
      • HAP: Occurs 48 hours or longer after hospitalization and not present at time of admission
      • Ventilator-associated  (VAP): Occurs more than 48 hours after endotracheal intubation
      • Associated with longer hospital stays, increased costs, sicker patients, and increased risk of morbidity and mortality
  • Multidrug-resistant (MDR) organisms are major problem in treatment
    • Staphylococcus aureus
    • Gram-negative bacilli
  • Risk factors
    • Advanced age
    • Immunosuppression
    • History of antibiotic use
    • Prolonged mechanical ventilation