Aspiration pneumonia natural history, complications, and prognosis

Aspiration pneumonia occurs following aspiration of different materials and particles. Natural history, complications, and prognosis are different for each category. Chemical pneumonitis usually develop after aspiration of gastric acid and might present acutely within two hours. Rapid clinical recovery or worsening of respiratory distress and hypoxemia might happen. Bacterial infection following aspiration is slower that other community-acquired pneumonia and might be acute, subacute, or chronic. Foreign body aspiration might present acutely with mechanical obstruction or chemical pneumonitis. Patients might present acutely with inflammation and cough, fever, and dyspnea. However, they might be asymptomatic and present with an incidental mass on radiographs. Complications of aspiration pneumonia include segmental or lobar pneumonia, bronchopneumonia, bronchiectasis, lung abscess, pleural empyema, respiratory failure, bacteremia, and shock.

• Aspiration pneumonia occurs following aspiration of different materials and particles. Natural history, complications, and prognosis are different for each category.^{[1][2][3][4][5][6][7][8][9][10][11]}

• The symptoms of chemical pneumonitis usually develop after aspiration of gastric acid.
• Following aspiration, onset of respiratory distress and cyanosis occurs within 2 hours.
• The clinical course following chemical pneumonitis might be rapid clinical recovery or worsening of respiratory distress and hypoxemia.
• Pulmonary fibrosis might happen even after recovery.

• Bacterial infection following aspiration is slower that other community-acquired pneumonia.
• Cough, fever, purulent sputum, and dyspnea are typical symptoms of aspiration pneumonia.
• Anaerobic infections may last several days or weeks and the patients may present with anemia and weight loss.
• Later, the patients may present with following complications including lung abscess, necrotizing pneumonia, or empyema.

• Foreign body aspiration might present acutely with mechanical obstruction or chemical pneumonitis.
• Foreign body aspiration is more common in children from one to three years of age.
• Foreign body might be visualized on chest radiographs.
• The Heimlich maneuver is recommended to remove foreign body from respiratory tract.

• Lipoid pneumonia might happen following aspiration of oil.
• Patients might present acutely with inflammation and cough, fever, and dyspnea. However, they might be asymptomatic and present with an incidental mass on radiographs.

• Complications of aspiration pneumonia include:
  • Segmental or lobar pneumonia
  • Bronchopneumonia
  • Bronchiectasis
  • Lung abscess
  • Pleural empyema
  • Respiratory failure
  • Bacteremia
  • Shock
  • Death

• Aspiration pneumonia prognosis is generally good, and mortality rate of patients with aspiration pneumonia is approximately 10.6-21%.^[8]
• The presence of underlying neurologic diseases that affect cough reflex is associated with a particularly poor prognosis among patients with aspiration pneumonia.

​