03.02 Aneurysm & Dissection

We are going to talk about three specific conditions in this lesson. Cerebral aneurysms, which are the leading cause of nontraumatic subarachnoid hemorrhages, aortic aneurysms, both thoracic and abdominal, and aortic dissections where time is really not on your side.

We know what an aneurysm is, that weakening of a vessel wall that causes a sort of ballooning out of the vessel, like in the picture here. When it comes to cerebral aneurysms, there are some very specific signs. The pain the patient will report will be sudden, intense and unrelenting. I have had patients tell me it feels like thunder and lightning, or getting hit in the head with a bad. They can have an altered level of consciousness. They become photophobic, the lights of the ED become painful. They can have nuchal rigidity and sometimes nausea and inevitable vomiting. 

With these patients, we want to get an immediate head CT to identify the location and severity of the aneurysm. 

In aortic aneurysms, these patients will complain about pain in the back, the shoulders and possibly the abdomen and they might be having trouble breathing. Why, well the swelling in the ascending aorta is putting pressure where there should not be pressure. Depending on the size of the aneurysm can determine the severity of their symptoms. 

Abdominal aneurysms, also known as the dreaded triple A, we see some very specific symptoms. You can actually feel a pulsating mass where the aneurysm is. If you place your stethoscope over the spot, you will hear a bruit...or the whoosh whoosh of the blood flowing through it. They might be tender to palpation over the abdomen and in some cases can present with hematoma over the flank area.

There are some pretty classic signs when it comes to aortic dissection. If we suspect this, we need to get blood pressures in both arms. If they are dissecting, one will have a systolic significantly lower than the other...a minimum of 20 mm or mercury below the other, and sometimes you may not be able to get one at all. They can have pale or pulseless lower extremities. Remember, they now have a hole in their aorta, so it stands to reason that blood is not getting to where it needs to be. The separation of the vessel can cause ripping or tearing chest pain. And trust me, you will know. They can have an altered level of consciousness, again...blood not getting where it needs to be. And overall there color looks awful, pale, gray, and diaphoretic.

If we have any suspicion of aortic involvement, we need some immediate diagnostics. A chest X-ray might show us a widened mediastinum. We can get a transthoracic echo to visualize the dissection and if we have time, a chest CT or CTA to see exactly what we are dealing with.

So how to we treat these cases. With the cerebral patients, we need to keep an eye on the airway. With the diminishing LOC, these patients will have difficulty protecting their own airway. After we secure the airway, we want to make sure we prevent further bleeding. We do that by maintaining that systolic between 90 and 140. We can use any mix of meds to do this but always work with the physician on that. With that crazy pain, we want to give some IV pain meds. And with that pain, can come increased anxiety so we might want to consider some IV benzos as well. 

We need to keep up our neuro assessments, and possibly insert an intracranial pressure monitor if we suspect that pressure is becoming dangerous. This will be neuros call most likely. And if we think there has been a rupture, its straight to the OR for an emergency craniotomy.

Much like with our neuro cases, it is important to keep that blood pressure from getting too high. The more pressure there is on the vessel wall, the higher the risk of rupture. That being said, we don't want to decrease the pressure too low as to decrease the perfusion to our vital organs. I know, there is a delicate balance that has to be found in these cases

Many of the more severe cases will require surgery. Two of our main options here are a triple a resection, basically cutting out the aneurysm and rerouting the vessel, or an EVAR, or endovascular aneurysm repair. That is where a stent is placed inside the vessel to prevent further pressure on the walls. If you look at this picture you can see how its done. The stent is slid into place then expanded to protect the walls of the vessel.

When dealing with a true dissection we need to move fast. Get these patients on oxygen and insert 2 large bore IV’s. no room for 22s here, were talking 16 gauge or better. They are going to need fluids and possibly blood products and they are going to need them fast. We need continuous monitoring of the blood pressures in both arms and we need to watch any trends there. We want to give IV nitroprusside or nitroglycerin for vasodilation. We will give IV beta blockers to decrease contractility. We basically want to avoid putting any more pressure on that dissection. Pain meds is obvious here and these patients need to get to the or for surgical repair of the dissections.

We need to always remember our A&P. Where is the problem happening and why.

Perfusion is key here. We need to protect the patient from bleeding out but we also need to make sure we don't damage any of the vital organs.

Ans as with many other cases, we need to prioritize. We may want to address the dissection first, but remember…. is the patient breathing?