What symptom would suggest a potential aortic dissection that requires immediate attention?

The symptom that suggests a potential aortic dissection requiring immediate attention is abrupt and severe back and epigastric pain. Aortic dissection typically presents with sudden onset of severe pain that can be described as tearing or stabbing, often radiating to the back or epigastric area. This type of pain occurs because the dissection creates a tear in the aorta, leading to different symptoms based on the area affected and potentially compromising blood flow to vital organs.

In this context, the pain is characterized by its abrupt onset and intensity, which are key indicators of a life-threatening condition that needs prompt medical evaluation. Recognizing these symptoms is critical for timely intervention, which can greatly influence outcomes in cases of aortic dissection.

The other symptoms listed do not indicate an acute emergency like aortic dissection. Severe leg swelling after a long flight could suggest deep vein thrombosis; lower back pain after lifting may indicate a muscle strain; and sharp calf pain that improves with rest might suggest intermittent claudication or other issues, but none of these are associated with the acute and catastrophic nature of an aortic dissection.