Mendelson syndrome

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

The etiologic agents is believed to be aspiration of acidic stomach contents, other compounds, e.g. bile, may also play a role. 

The chemical, burn and  cause occlusion of bronchi and bronchioles damaging the epithelium typically leading to lung edema (ARDS). Secondary bacterial superinfection may also develop.

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

  • tachypnoeic
  • hypoxic
  • febrile

Other signs include

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

Usually ​there is minimal sputum production ref needed.

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

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

Share article

Article information

rID: 14084
Section: Syndromes
Tag: refs, cases
Synonyms or Alternate Spellings:
  • Mendelson's syndrome
  • Gastric acid aspiration
  • Gastric acid aspiration syndrome
  • Peptic pneumonia
  • peptic aspiration pneumonia

Support Radiopaedia and see fewer ads

Updating… Please wait.

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.