What is the next step in management for a patient with trauma to the chest and a widened mediastinum on chest X-ray (CXR)?

Immediate CT Angiography of the Chest

A widened mediastinum on chest X-ray following blunt chest trauma mandates immediate CT angiography (CTA) to evaluate for traumatic aortic injury, which is present in approximately 44% of such cases and carries significant mortality risk. 1, 2

Primary Diagnostic Approach

Hemodynamically Stable Patients

• Proceed directly to CT angiography with IV contrast, which provides sensitivity approaching 100% and specificity of 98-99% for diagnosing thoracic aortic rupture 1, 3
• CTA is the most commonly used and appropriate initial definitive imaging modality due to near-universal availability, ability to image the entire aorta, and short examination time 4, 3
• Transthoracic echocardiography (TTE) should be performed concurrently to evaluate for cardiac injuries, particularly if cardiac troponins are elevated or ECG shows abnormalities 4

Hemodynamically Unstable Patients

• Transesophageal echocardiography (TEE) is preferred for patients requiring close monitoring who cannot be transported to CT 3, 5
• TEE has 100% sensitivity and 75% specificity for mediastinal hematoma, with the ability to be performed rapidly at bedside 5
• The distance between the esophageal probe and aortic wall >3mm is the most accurate TEE sign of traumatic mediastinal hematoma 5

Critical Management Steps

Immediate Actions

• Obtain urgent surgical consultation immediately upon identifying widened mediastinum, regardless of imaging results 1, 3
• Monitor ECG and cardiac troponins continuously, as rising troponins or new arrhythmias indicate need for echocardiography 4
• If aortic dissection is confirmed, initiate immediate heart rate control with IV beta-blockers and reduce systolic blood pressure 3

Understanding the Clinical Context

While widened mediastinum has 100% sensitivity for aortic injury, the positive predictive value is only 0.4-1% because most patients (74%) have either no traumatic findings or nontraumatic causes (pericardial effusion, lymph nodes) 6. However, the high mortality of missed aortic injury (which occurs in 44% of cases with widened mediastinum in some series) mandates definitive imaging in all cases 2.

Common Pitfalls to Avoid

• Never rely on chest X-ray alone to exclude aortic injury—a completely normal chest X-ray does not exclude aortic dissection, and chest X-ray misses 80% of hemothorax cases 4, 3
• Do not delay imaging for additional chest X-rays or clinical observation; the finding of widened mediastinum itself triggers the need for definitive imaging 4, 1
• If initial CTA is negative but clinical suspicion remains high, obtain a second imaging study using a different modality (TEE or MRI) 3
• Be aware that tracheal deviation to the right is a specific sign of aortic dissection or rupture caused by mediastinal hematoma 1

Additional Thoracic Injuries to Evaluate

The CTA will simultaneously identify other life-threatening injuries that commonly accompany widened mediastinum 4:

• Hemothorax or hemopericardium (missed in 80% of cases on chest X-ray alone) 4
• Sternal fractures (present in 4% of widened mediastinum cases) 6
• Rib fractures, particularly ribs 3-9, which suggest cardiac or pericardial injury 4
• Vertebral fractures and pneumomediastinum 6