Aspiration pneumonia and pneumonitis: Difference between revisions

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==Background==
==Background==
*Difficult to predict which patients with pneumonitis will go on to develop pneumonia, aspiration alone does not cause pneumonia
*Difficult to predict which patients with pneumonitis will go on to develop pneumonia, aspiration alone does not cause pneumonia
*Witnessed aspiration key to distinguishing between the two
*Aspiration pneumonitis
*Aspiration pneumonitis
**Inflammatory chemical injury of tracheobronchial tree and pulmonary parenchyma
**Inflammatory chemical injury of tracheobronchial tree and pulmonary parenchyma
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**Increased sensitivity, specificity, and overall accuracy compared to CXR
**Increased sensitivity, specificity, and overall accuracy compared to CXR
**Reasonable to obtain even if CXR negative if clinical suspicion is high
**Reasonable to obtain even if CXR negative if clinical suspicion is high
**Aspiration is a risk factor for pulmonary abscess formation


==Management==
==Management==

Revision as of 07:16, 15 January 2021

Background

  • Difficult to predict which patients with pneumonitis will go on to develop pneumonia, aspiration alone does not cause pneumonia
  • Witnessed aspiration key to distinguishing between the two
  • Aspiration pneumonitis
    • Inflammatory chemical injury of tracheobronchial tree and pulmonary parenchyma
    • Due to inhalation of regurgitated sterile gastric contents
    • Must aspirate at least 20-30mL of gastric contents with pH <2.5
    • Can lead to aspiration pneumonia due to pulmonary defense mechanism injury
  • Aspiration pneumonia
    • Alveolar space infection secondary to inhalation of pathogenic material from oropharynx
    • Result of a complex interplay of the aspirated material, aspirated volume, pH, patient physiology and pulmonary defense mechanisms
    • Increased in patients with periodontal disease, chronic colonization of upper airways, or taking PPI/H2-blockers
    • Accounts for up to 20% of community-acquired pneumonia in elderly, majority of nursing home-acquired pneumonia
    • Microbiology

Risk factors

  • Advanced age
  • Altered level of consciousness
  • Anatomic abnormality of upper airway
  • Dementia
  • Esophageal disorders
  • Gastroesophageal reflux
  • Neuromuscular disease
  • Poor oral hygiene
  • Prior history of aspiration
  • Prolonged supine position
  • Retained gastric material
  • Tube feedings

Clinical Features

Differential Diagnosis

Acute dyspnea

Emergent

Non-Emergent

Evaluation

Work-Up

  • CXR
    • Unilateral focal or patchy consolidations in dependent lung segments
    • Right lower lobe is most common area; bilateral patterns can also be seen
    • Lower lobe infiltrate when aspiration occurs in upright position
    • Upper lobe infiltrate when aspiration occurs in recumbent position
  • CT
    • Increased sensitivity, specificity, and overall accuracy compared to CXR
    • Reasonable to obtain even if CXR negative if clinical suspicion is high
    • Aspiration is a risk factor for pulmonary abscess formation

Management

Disposition

  • Admit all patients with aspiration pneumonia
  • For aspiration pneumonitis, consider discharge if:
    • Otherwise healthy and non-toxic
    • Give outpatient antibiotics if symptomatic for >48hrs
  • For aspiration pneumonitis, consider admission for:
    • Chronically ill or immunocompromised
    • Nursing home patient

See Also

References