 Welcome to emergency medicine video on aortic dissection. In this part, we'll discuss the presentation. In part 2, we'll discuss the investigations and treatment. What is aortic dissection? It occurs when there is a tear in the media of the aorta. The blood now creates a false lumen. The column of blood in the false lumen can keep dissecting further. Or it can propagate backwards. Aortic dissection is a must-not-miss diagnosis in the emergency department, since the mortality is very high. Aortic dissection kills in different ways. Number 1. The false lumen ruptures. Patient now exsanguinates. These patients often die before they can reach the hospital. Number 2. Let's look at the blood in the false lumen. Often, the blood in the false lumen clots. When the major arteries comes off the aorta, those coming off the section with the dissected flap, we feel a clot of blood and therefore are leading to ischemia to wherever these major arteries are leading to. That leads to infarction from various organs, ranging from the brain, the GI tract, the kidneys and so on. The third problem for aortic dissection has to do with the heart. A dissection can propagate backwards and start bleeding into the pericardium. As time goes on, that can cause a cardiac tamponade leading to death. Sometimes, the aortic dissection can dissect into the coronary arteries and cause myocardial infarction, although that's rare. What are the risk factors for aortic dissection? As you can imagine, anything structural will cause the media to be more likely to tear. It can include things like connective tissue disease, such as Marfan's and Ehler-Danlos syndrome. It can also involve aortic valve that's not normal, such as a bicuspid valve and aortic coarctation. Surgery such as aortic valve replacement and bypass surgery increase the risk of aortic dissection. The most important cause, however, is hypertension. This is the number one risk factor for aortic dissection. How would aortic dissection present? There are two parts of the presentation. Pain and what target organs are being affected. Let's go through them one by one. The classic pain for aortic dissection is a back pain. This pain is intrascapular, severe, sudden and onset, and maximum at onset. Patients sometimes can describe it as a tearing pain. The pain may sometimes radiate to the interior chest. In terms of end organ effects, it is all based on which end organs are being affected. If the carotid arteries are being affected, the patient will present with a CVA. If the pericardium is affected, then the patient might present with syncope or tamponade. If the gut vessels are being affected, then the patient can present with ischemic gut. If the vessels like the iliacs are affected, the patient might present with ischemic limb symptoms. Therefore, as you can see, based on the end organs that are being affected, the presentations may vary. We now move on to physical examination. We'll separate this into vital signs and specific end organs effects. As you may expect, on vital signs, the patient is usually hypertensive, with the exception that if they are in tamponade, then they will be hypotensive. However, for most of the patients, the patient's blood pressure would be high. Depending on where the flap is, there might be a difference between the patient's right arm and left arm blood pressure. It would usually be more than 20 to 30 millimeters mercury between the left and the right arm. Let's look at end organ effects. Based on what we discussed earlier, what do you think should be the physical signs of patients with aortic dissection? We'll be looking for signs of CVA, signs of tamponade. We would also look for an aortic insufficiency murmur. We'll look for presentation of an ischemic gut, and signs and symptoms of an ischemic limb. What about atypical presentations? The literature is rich with atypical cases for aortic dissection. They're atypical in that either their pain is not typical, or the end organ effects are transient or limited. This has made aortic dissection very difficult to diagnose in the emergency department. For the sake of this module, what we'd like you to remember is the classic signs and symptoms of aortic dissection. The tearing, severe back pain, in conjunction with other signs such as CVA, tamponade, ischemic gut, or ischemic limbs. We hope you find this useful. In part two, we'll discuss the diagnosis and treatment. Thank you for watching.