Aortic aneurysm

helpful in the majority of other causes of pain and can decrease the rate of a negative laparotomy. Obvious symptoms and signs of a surgical abdomen, however, are best evaluated with a laparotomy.

Pain can be treated, particularly after the examination. Consider morphine or fentanyl intravenously as these will decrease the patient’s anxiety and will not mask the evidence of peritonitis. There is no evidence that treating the pain has an adverse effect on the patient’s outcome and will keep the patient more comfortable during the workup of the pain.

AORTIC ANEURYSM

In the emergency room, managing an aortic aneurysm usually means managing an aortic dissection. With an aortic dissection, there is a tear in the intimal layer of the artery with blood surging through the tear, leading to a false passage and secondary hemorrhage. Any part of the aorta may be affected with a dissection. The major predisposing factor for this is hypertension.

Patients with an aortic dissection can have the sudden onset of chest or back pain that can be severe. About 20 percent of patients die before they are seen in the ED, while an additional third will die in surgery or from postoperative complications. It is particularly common in African-Americans, the elderly, and those with underlying hypertension. The peak ages are between 50 and 65 years of age. Patients who have Ehlers-Danlos syndrome or Marfan syndrome have an increased risk of dissection at a younger age. Figure 1 shows what a dissecting aortic aneurysm looks like:

Figure 1.

There are a couple of ways to classify an aortic dissection. The DeBakey classification involves three types:

• Type I—the dissection begins in the ascending aorta and extends to the aortic arch.

• Type II—These start in the ascending aorta and are confined to this area.

• Type III—this is the least common and starts in the descending aorta. It may be above or below the diaphragm.

With the Stanford system, there are two types. In type A, the ascending aorta is involved, while in type B, the descending aorta is involved.

The aorta is under varying degrees of hydraulic stress. The two areas most vulnerable are the right lateral aspect of the ascending aorta near the aortic valve and the proximal descending aorta.

Dissections happen with preexisting aortic disease, such as atherosclerosis, hypertension, and connective tissue diseases like Marfan syndrome and Ehlers-Danlos syndrome. Smoking, cocaine use, and dyslipidemia all contribute to atherosclerosis.

The major complications of an aortic dissection include having a compromise in the circulatory status in branches off the aorta, aortic valve regurgitation, heart failure, and

rupture of the aorta into the pericardium, pleural space, or right atrium. This last complication is commonly fatal.

The patient will have the sudden onset of pain between the scapula, chest pain, or abdominal pain. The person will feel a ripping kind of pain and comes on suddenly. The pain will migrate as the dissection gets larger with about one-fifth of patients having syncope for a variety of reasons, including pain and aortic baroreceptor activity. Interruptions in blood flow can lead to a myocardial infarction, stroke, intestinal infarction, paraplegia, or renal failure.

The diagnostics of an aortic aneurysm include listening for an aortic regurgitation murmur, seen in half of all patients. One-fifth of patients will have decreases in pulses noted in one or more artery and heart failure can be seen if aortic regurgitation is present. Pleural effusions can be seen if blood or inflammatory fluid builds up in the pleural space. Cardiac tamponade can occur.

Tests used to confirm the diagnosis include a transesophageal echocardiogram, magnetic resonance angiography, or CT angiography. Unequal pulses in the extremities should trigger these diagnostic tests. A chest x-ray will often show mediastinal widening from an underlying aneurysm. The CTA test is often the most available with a positive predictive value of 100 percent. MRA is the best test in terms of sensitivity and specificity but it is not suited for emergency detection of the aortic aneurysm. Contact a vascular surgeon early in the diagnostic process.

The treatment in the emergency department is beta blockers to decrease blood pressure and prevent furthering of the dissection. Both endovascular and open repair can be used as definitive treatment for an aortic dissection. Intra-arterial blood pressure monitoring and urine output monitoring are used for the patient who doesn’t require emergency surgery. Don’t forget to type and crossmatch for a minimum of 4 units of packed red blood cells if surgery is anticipated.

Blood pressure reducers for an aortic dissection include metoprolol, labetalol, esmolol, verapamil, or diltiazem. If nitroprusside is to be used, it should never be used alone as it will activate the sympathetic nervous system if not given along with a calcium channel blocker or beta blocker.