Pulmonary contusion

A pulmonary contusion refers to an interstitial and/or alveolar lung injury without any frank laceration. It usually occurs secondary to non-penetrating trauma. There is a significant risk of ventilator-associated pneumonia in a ventilated trauma patient that have pulmonary contusions, which carries a high mortality (up to 50%) ⁶.

Epidemiology

Contusions follow blunt or penetrating chest trauma, are almost always seen with other chest (and abdominal) injuries. While contusion can affect anyone, children are considered more susceptible due to chest wall greater pliability in that age group, especially to pulmonary laceration.

Radiographic featuresPathology

In most casesContusions follow blunt or penetrating chest trauma, the findings are manifest at the time of the initial examination and show little tendency to increase in severityalmost always seen with subsequent examinationsother chest (and abdominal) injuries. Radiographic clearing of pulmonary contusion is relatively rapid, and the signs of contusion have often resolved within 48 hours. By day 10 they should have resolved completely ³. If the consolidation progresses after a day or two after the traumatic injury, then superimposed aspiration, atelectasis and infection should be considered.

Location

Features are often not localised in a lobar or segmental pattern. Contusions usually occur adjacent to bony structures (as fractures cause the contusions), and are hence seem to be peripherally located ⁵.

RadiographPlain radiograph

An initial trauma chest radiograph may be normal. Over the first day following trauma, ill-defined geographic consolidation develop which are not sensitive for contusion, with differentials including aspiration, atelectasis and infection.

Consolidation may be faint and usually shows rapid improvement with time, commonly over several days as the blood in the alveolar spaces is absorbed.

CT

Typically seen as focal, non-segmental (typically crescentic) areas of parenchymal opacification, usually peripheral. Can have subpleural sparing with smaller contusions which can be a distinguishing feature. More common posteriorly and in lower lobes.

Treatment and prognosis

In most cases, the findings are manifest at the time of the initial examination and show little tendency to increase in severity with subsequent examinations. Radiographic clearing of pulmonary contusion is relatively rapid, and the signs of contusion have often resolved within 48 hours. By day 10 they should have resolved completely ³.

If the consolidation progresses after a day or two after the traumatic injury, then superimposed aspiration, atelectasis and infection should be considered.

There is a significant risk of ventilator-associated pneumonia in a ventilated trauma patient that have pulmonary contusions, which carries a high mortality (up to 50%) ⁶.

Differential diagnosis

General imaging differential considerations include

• aspiration pneumonia
• segmental / focal atelectasis
• pulmonary haemorrhage
• pneumonia
• fat embolism

See also

• pulmonary laceration