Pneumonia

Pneumonia

• 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.

Etiology

• 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