1) Aortic dissection is uncommon.  Myocardial infarction is roughly 500 times more common.  When considering the diagnosis, look for risk factors including hypertension, genetic conditions (Marfan's, Ehlers-Danlos, Turner, bicuspid aortic valve, significant family history), recent PCI/surgery and a known dilated aorta.

2) Initial presentation is often abrupt onset, severe, anterior thoracic pain. Hypertension is often present initially.  Other signs and symptoms are those related to complications including aortic regurgitation, MI, syncope, pulse deficit, stroke.

3) The main causes of shock in aortic dissection are cardiac tamponade, heart failure associated with severe aortic regurgitation and hypovolemic shock due to aortic rupture.  Coronary involvement is rare, with the right coronary artery more commonly affected. The utility of D-dimer is not clearly established.  Bedside ultrasound can be a useful adjunct. Look for a dilated ascending aorta, aortic regurgitation, pericardial effusion, hemothorax, and right coronary artery territory regional wall motion abnormality.  

4) CT-Angiography (ekg gated) is the diagnostic test of choice in the emergency department. A CT-PE protocol may miss a dissection. It may be helpful to order a “double rule out scan” if both pulmonary embolism and dissection are on the differential.  In addition, noncontrast images are useful in assessing features including intimal calcification, hemorrhage, hematoma.

5) Management of a confirmed dissection involves rapidly lowering the blood pressure and heart rate. Beta-blockers (usually, labetalol) are first line and nitroprusside can be added on.  Urgent surgery is indicated to diminish life-threatening complications including aortic rupture, pericardial tamponade and progression of the dissection.