Aspiration pneumonia

Dr Vincent Tatco and Radswiki et al.

Aspiration pneumonia is caused by a direct chemical insult due to the entry of a foreign substance, solid or liquid, into the respiratory tract.

Aspiration may be clinically silent, or it may present with dyspnoea, cough or fever. The clinical and radiographic features depend on the aspirated volume, pH and chronicity 2.

According to time of onset it may be divided into two groups:

The clinical and radiological manifestations are protean, varying from asymptomatic focal inflammatory reaction with few or no radiological abnormalities to severe life-threatening disease.

Risk factors
  • alcohol intoxication
  • general anaesthesia
  • loss of consciousness
  • structural abnormalities of the pharynx and oesophagus
  • neuromuscular disorders
  • swallowing disorders
  • laparoscopic gastric banding
Plain radiograph

A chest x-ray may demonstrate airspace opacification in a lobar or segmental distribution. There may be a gravity dependent predilection.


The posterior segment of the upper lobes and the superior segment of the lower lobes are most commonly involved lung sites when aspiration occurs in a recumbent patient. In an erect patient, aspiration is more likely to involve bilateral basal segments, right middle lobe and lingula 2.

Aspirated low-density organic material such as mineral oil in the tracheobronchial tree or alveolar spaces cannot be diagnosed on plain radiographs, but they can be demonstrated on CT scans.

Opaque aspirates are also well demonstrated on CT scans.


The major complication associated with aspiration is pulmonary infection:

Other causes of airspace opacity need to be considered 3:

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Article Information

rID: 12302
System: Chest
Section: Gamuts
Synonyms or Alternate Spellings:
  • Aspiration pneumonitis
  • Aspiration bronchopneumonia
  • Aspiration bronchopneumonitis
  • Aspiration pneumonias

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