05. Aspiration Pneumonitis and Pneumonia

Overview

  • Aspiration pneumonitis can present with a fever, cough, elevated WBC and CXR opacities. However, aspiration pneumonitis may not require treatment with antibiotics. Symptoms usually resolve within 24-48 hours, though some may develop secondary bacterial infections or progress to aspiration pneumonia. Use the guidelines below to differentiate from aspiration pneumonia. 
  • Aspiration pneumonia is less commonly caused by anaerobes. It is predominantly caused by gram-negative rods, so make sure to cover with a broad spectrum antibiotic, just as you would for a typical hospital-acquired pneumonia. Consult the UCSF IDMP website for the latest up-to-date antibiogram, including ICU-specific/unit-specific recommendations.
  • Percutaneous gastrostomy (PEG) tubes and NG tubes do not prevent or reduce the incidence of aspiration pneumonia.

Aspiration Pneumonitis

  • Patients at risk are those with a depressed level of consciousness (associated with decreased cough reflex), dysphagia, a neurologic disorder, or vomiting. This includes patients who are intoxicated, sedated, or have a head injury/pathology.
  • Results from aspiration of sterile gastric contents; acute lung injury results from acidity and particulate material. Subsequent superinfection is possible.
  • Suction and clearance of gastric contents is important, but may not prevent chemical injury, which happens immediately.

Aspiration Pneumonia

  • Common: 5-15% of pneumonia hospitalizations are associated with aspiration.
  • Patient risk factors: older age, altered mental status, dysphagia, gastric dysmotility, PPI use.
  • Results from aspiration of colonized oropharyngeal material and is therefore not sterile.
  • Pathogens: mainly gram-negative rods and gram-positive cocci. Less commonly due to anaerobic bacteria.
  • Clinically presents as typical pneumonia with tachypnea, fever, cough.

Management

  • Suction the upper airway after a witnessed aspiration event and intubate if the patient can’t protect airway.

Aspiration pneumonitis:

  • If symptoms >48 hours: treat with levofloxacin or ceftriaxone. Resist the urge to give prophylactic antibiotics <48 hours, as this will simply select for more resistant organisms.

Aspiration pneumonia:

  • Community acquired, non-severe:
    • Ceftriaxone 1-2g IV daily or Augmentin 875 mg PO BID.
    • Routine anaerobic coverage is not recommended unless imaging is consistent with lung abscess or empyema.
    • Duration of therapy is not well studied, though 7 days is typical for uncomplicated pneumonia (i.e. no empyema).
  • For guidance on management of severe CAP or hospital acquired pneumonia, see section Pneumonia for details and consult the UCSF IDMP website.


 

El-Solh AA, Pietrantoni C, Bhat A, et al.  Microbiology of severe aspiration pneumonia in institutionalized elderly. Am J Respir Crit Care Med 2003;167:1650-1654.

Marik PE. Aspiration pneumonitis and aspiration pneumonia. N Engl J Med 2001 344:665-671.

Raghavendran K, Nemzek J, Napolitano LM, and Knight PR. Aspiration-Induced lung injury. Crit Care Med. 2011 39:818-826.

Joshua P. Metlay, Grant W. Waterer, Ann C. Long, Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American Journal of Respiratory and Critical Care Medicine. 2019, e45-e67.