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This patient with a fall >3 m [10 ft] followed by rapid deceleration (landing on pavement) is at risk for blunt thoracic aortic injury (BTAI) because the abrupt change in velocity exerts a combination of stretching, shearing, and torsional forces capable of rupturing the aorta.  Patient presentation depends on the degree of aortic rupture; those with an incomplete rupture (as with this patient) may be normotensive to hypertensive (due to sympathetic response) and may initially appear stable even though they have a life-threatening injury.

All patients with blunt chest trauma require a chest x-ray after primary trauma survey.  Although patients with BTAI may have a normal chest x-ray, findings concerning for BTAI include:

• Widened mediastinum or abnormal aortic contour (eg, enlarged aortic knob) from either an intimal tear (creating a secondary, false lumen similar to aortic dissection) or incomplete rupture of the intima and media (where the adventitia expands under high-flow pressure)
• Left-sided effusion (ie, hemothorax) from aortic bleeding into the thorax

Diagnosis can be confirmed via CT angiography for hemodynamically stable patients or transesophageal echocardiography (likely in the operating room) for unstable, hypotensive patients.

(Choice B)  Diaphragmatic rupture typically presents with loss of diaphragmatic contour and/or presence of abdominal organs (eg, stomach, bowel) within the thoracic cavity, which may cause a mass-effect mediastinal shift (but not widening).

(Choice C)  Left ventricular aneurysm appears as a prominence or bulge along the left heart border, not as a widened mediastinum.  It is typically seen as a complication of transmural myocardial infarction rather than trauma.

(Choice D)  Myocardial contusion has no specific chest x-ray findings, although sternal fracture should raise suspicion.  It is typically diagnosed by ECG (showing arrhythmia or new bundle branch block) or echocardiography (showing wall motion abnormality or decreased contractility).

(Choice E)  Pulmonary contusion causes parenchymal hemorrhage and edema that manifests as irregular, nonlobular opacities.

(Choice F)  Tracheobronchial disruption may cause mediastinal widening due to rapid efflux of air from the injured tracheobronchial tree; however, air would be visualized as pneumomediastinum.  In addition, pneumothorax and/or subcutaneous emphysema would likely be present.

Educational objective:
Patients with trauma from rapid deceleration are at risk for blunt thoracic aortic injury (BTAI).  All patients with blunt chest trauma require a chest x-ray after initial trauma survey.  Chest x-ray findings concerning for BTAI include widened mediastinum, abnormal aortic contour, and/or left-sided effusion (hemothorax).