Abdominal Aortic Aneurysm

Localized dilation of the aorta, most commonly below the renal arteries due to lack of vaso vasorum.

=Objectives=
 * Understand the mechanism for a AAA.
 * Understand the component of a AAA that determines management.
 * Understand the best diagnostic steps

=Symptoms= =Mechanism=
 * 1) Asymptomatic
 * 2) Pulsations in the abdomen, chest, lower back, scrotum.
 * 3) If ruptured: severe pain in lower back, flank, abdomen, and groin
 * 1) Degradation of tunica media
 * 2) Aneurysm
 * Risk Factors
 * Atheroscerlosis
 * Smoking
 * Hypertension
 * Family History
 * Age > 55 yrs

=Differential Diagnosis=
 * 1) Abdominal Aortic Aneurysm: usually hypotensive at presentation if ruptured
 * 2) Aortic Dissection: usually hypertensive at presentation

=Diagnostic Workup=
 * 1) Physical Exam: deep palpation of abdomen for pulsatile mass
 * 2) Ultrasound: other imaging as necessary

=Management= First determine if the patient is symptomatic. If the patient is symptomatic then surgery is recommended to prevent complications: rupture.

Second, determine the size. If it is >6cm it will be surgically repaired, regardless if it is symptomatic.

If it is <6cm and asymptomatic, have your patient follow up as an outpatient with ultrasounds every 3 months to determine if there has been any change in size.

Key to floor management will BP control.

=Pimping Points=
 * True vs. false aneurysm: False aneurysm does not involve all aortic layers. True aneurysm involves all aortic layers.
 * Types of aneurysms:
 * Fusiform: circumferential dilation
 * Saccular: one sided dilation


 * More common in men


 * All men above the age of 60 should have screening ultrasound.


 * Mortality of abomdinal aortic aneurysm rupture: 90%
 * Retroperitoneal vs. intraperitoneal ruptures
 * Retroperitoneal: associated with decreased mortality because peritoneum contains the rupture
 * Intraperitoneal: associated with increased mortality due to increased volume of intraperitoneal space

=Floor Fodder=
 * There's an interesting discussion of pathogenesis theories at Wikipedia: Pathophysiology

=Study Questions= The goal here is to use the objectives to increase retention of the information you have just read. Questions should be high yield. Include an explanation below the question with the answer. Leave a little space so that you can read the question without seeing the answer.

=Resources=