Correct!
4. Thoracic CT scan
Limb pulse deficit is a classical finding of ascending aortic dissection, but is not often noted. Blood pressure discrepancy > 20 mmHg is more likely to be present. The other key clinical findings of ascending aortic dissection are “ripping or tearing” chest pain and widened aorta on chest radiography. Although the left mediastinum width in this patient’s CXR (7cm) is technically widened (> 6cm), the clinicians did not notice this until later. The key finding was the pulse deficit, supported by the vague history of chest pain. When the intensivist mentioned to the ER nurse that he thought the patient might be dissecting his aorta, she said that was what she thought all along. She was invited to share her diagnostic musings more openly in the future. Rapidly confirming the diagnosis by thoracic CT scan or transesophageal echocardiography is the most important next step.
The thoracic CT scan is shown in Figure 2.
Figure 2. Representative images from the contrast-enhanced thoracic CT scan in soft tissue windows.
What is the cause of the blockage of blood flow to the patient's arms and neck? (Click on the correct answer to proceed to the fourth of five panels)