Chemical pneumonitis is inflammation of the lung caused by irritation from aspirated vomitus or barium used in gastro-intestinal imaging, ingested gasoline or other petroleum distillates, ingested or skin absorbed pesticides, gases from electroplating, or other irritants. It is sometimes called a “chemical Chemical pneumonitis“, though it is not infectious. May also be caused by the use of inhalants.When the toxic substance is an oil, the Chemical pneumonitis may be called lipoid Chemical pneumonitis.

Mendelson’s syndrome is a type of chemical Chemical pneumonitis in which aspiration of gastric acid is present. It was first described in pregnant females who aspirated gastric content during anesthesia, with development of respiratory distress, cyanosis and lung infiltrates on chest X ray.^[1]

Chemical pneumonitis is inflammation of the lung caused by irritation from aspirated vomitus or barium used in gastro-intestinal imaging, ingested gasoline or other petroleum distillates, ingested or skin absorbed pesticides, gases from electroplating, or other irritants. It is sometimes called a “chemical chemical pneumonitis“, though it is not infectious. It may also be caused by the use of inhalants. When the toxic substance is an oil, the chemical pneumonitis may be called lipoid chemical pneumonitis.

Approximately 3 in 5 patients with chemical pneumonitis have clinical improvement with clearing of chest X ray. Approximately 1 in every 3rd patient shows a rapid improvement followed with a new progressive infiltrate that suggests a secondary superimposed bacterial infection or the development of ARDS. The least common course, but the one with the worst prognosis, is the development of fulminant disease resulting in acute death.