 Welcome to emergency medicine video. This segment is on abdominal aortic aneurysm. We will talk about its presentation, investigations and treatment. AAA is defined as the dilatation in the abdominal aorta. That's more than 3 centimeters. In terms of their location, most of them are found below the renal arteries and above the iliacs. As the AAA grows, it's more likely to rupture. The risk of rupture increases when the AAA is more than 5 centimeter in diameter. As it ruptures, the patient exsanguinate. Therefore, AAA is a must-not-miss diagnosis in the emergency department. There are a few risk factors for AAA. They include smoking, being male, increasing age, hypertension and family history of AAA. How do they present? The presentation of AAA can be divided into unruptured and ruptured AAA. Unruptured AAA is usually asymptomatic until they expand. When they do, the patient usually complains of pain. It's usually in their back, flank, abdomen, and sometimes radiate to the groin. On examination, the patient's vital signs should be normal. You might be able to palpate a pulsatile mass in the abdomen. When they rupture, the presentation is much more dramatic. The patient may still be complaining of pain in their back and flank area. Now the pain is much more severe and continuous. On examination, the patient is in shock. You will see hypotension, decreasing tissue perfusion, tachycardia and decreased level of consciousness. The patient with a AAA that's ruptured is a very sick patient. How do we diagnose a AAA? We diagnose it by diagnostic imaging. We'll talk about ultrasound and CT. Ultrasound can be done by the bedside. It is useful for diagnosing the dilated aorta. Therefore finding where the aneurysm might be. However, on ultrasound, we cannot tell whether the AAA has ruptured or not. That is because when AAA ruptured, it tends to go into the retropyrantinal space and therefore it cannot be picked up by the bedside ultrasound. On an ultrasound, a AAA will look like this. This is a ultrasound still image of a transverse look at the aorta. This is the abdominal wall. The patient's right and left are shown. This black circle here represents a AAA. When measured, the diameter is about 6 cm. Bedside ultrasound is a quick and easy way to diagnose AAA. It can be done quickly and it can also be done in patients who are unstable. However, it is not a perfect test. We talked about before how it will not tell you whether it has ruptured or not. Even though you might be able to tell that from the clinical symptoms of the patient. It won't tell you where it has ruptured. And in patients who have increased body mass index or have a lot of overlying bowel gas, it is sometimes impossible to visualize the aorta. Let's talk about CT. The sensitivity of CT for AAA is almost 100%. It will tell you how big the AAA is, where it has ruptured, and what branches are also involved. This is a still image from a CT scan. You can see the AAA here. You can also see retiparitino blood. The limitation of CT scan is that the patient needs to be stable enough to leave the emergency department. It also requires IV contrast. How do we treat a AAA? AAA should be treated by surgery. For the patient with an unruptured AAA, we should discuss the case by your consultant. For the patient with a ruptured AAA, they need to go to the operating room for definitive repair. Before the patient goes up to the OR, we need to resuscitate them in the emergency department. Like with all emergency department resuscitation, we start with ABC. If the patient's airway is not patented and if they're not ventilating properly, you may choose to intubate them and take over their ventilation and oxygenation. The main focus will be circulation. Since the patient with a ruptured AAA will be in hemorrhagic shock, we need to aggressively resuscitate them. That consists of fluid and blood. To do that, you need at least two large varieties. In terms of fluid, usually one to two liters of crystalloids is given. After that, and usually at the same time, two units of blood will be given in the patient before they go up to the operating room. Since we're expecting them to have blood allot internally. We also expect them to have more ongoing blood need in the operating room. Therefore, we can order more units of pegged red blood cells. And since the patient will likely undergo a massive transfusion, platelet and FFP is something that the anesthetist will probably order in the operating room. That will decrease the coagulopathy that's associated with massive transfusion. Once the fluid and blood resuscitation is ongoing, you can also order blood work at the same time. Things like CBC and coagulation study might be useful for the surgeons later on. In summary, we discussed why AAA is a must-not-miss diagnosis in the emergency department. It can be readily picked up by a bedside ultrasound. A rupture AAA patient needs to go to the operating room. However, we still need to resuscitate them aggressively before they do so. We hope you find it useful. Thank you for watching.