Clinical scenario

A 45 year old man attends the emergency department after being involved in a road traffic accident. He has sustained a blunt chest injury during the impact and has bruising across his chest wall. His ECG shows non-specific ST segment changes and the chest radiograph are normal. You wonder about the benefit of performing a troponin level to aid the diagnosis or exclusion of myocardial contusion.

Three part question

Is [troponin] level a good indicator of underlying [cardiac damage] after [blunt chest trauma]?

Search strategy

Medline 1966-11/04 using the Ovid interface. [exp troponin OR troponi$.mp] AND [exp Wounds, Nonpenetrating OR exp Thoracic Injuries OR blunt chest injury.mp OR blunt chest trauma.mp OR blunt thoracic injury.mp OR blunt thoracic trauma.mp] AND [exp Heart Injuries OR myocardial contusion.mp OR cardiac contusion.mp OR myocardial damage.mp OR myocardial injur$.mp OR cardiac damage.mp OR cardiac injur$.mp] LIMIT to human AND English language.

Search outcome

Altogether, 75 papers were found, of which 20 were directly relevant to the three part question. Of these, three were literature reviews, which covered six of the papers found, five were letters relating to other papers included, three were case reports and three were journal articles. The three review articles and the three journal articles not included in the reviews are shown in the table.

Comment(s)

There is no gold standard as yet for the diagnosis of myocardial contusion, which makes it difficult to assess the newer forms of detection of myocardial injury. Troponin T may be less sensitive than a troponin I in the context of blunt chest trauma. The diagnostic window for myocardial contusion appears to be smaller and occur earlier after the injury than in the case of myocardial infarction in some studies. Other papers suggest that levels should be taken at admission and at 4–6 hours.

CLINICAL BOTTOM LINE

An abnormal troponin level seems to be a sensitive indicator of myocardial damage.