Mendelson syndrome

Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia.

This syndrome develops rapidly (2-12 hours after aspiration) and within hours the patient may become

  • tachypneic
  • hypoxic
  • febrile

Other signs include

  • bronchospasm with need for increasing ventilation pressure
  • bronchial hypersecretion
  • pulmonary vasoconstriction
  • cyanosis

Usually ​there is minimal sputum production ref needed.

The primary pathogenesis is secondary to the aspiration of acidic stomach contents, although other compounds, e.g. bile, may also play a role. 

The chemical burns and causes occlusion of bronchi and bronchioles damaging the epithelium typically leading to pulmonary edema (ARDS). Secondary bacterial superinfection (aspiration pneumonia) may develop.

Plain film and CT may depict fleeting infiltrates (which do not last more than 1 or 2 days), atelectasis and non-cardiac lung edema.

It is named after the American anesthesiologist Curtis L Mendelson, who described it in 1946 2

Article information

rID: 14084
Section: Syndromes
Synonyms or Alternate Spellings:
  • Peptic aspiration pneumonia
  • Mendelson's syndrome
  • Gastric acid aspiration
  • Gastric acid aspiration syndrome
  • Peptic pneumonia

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