2 Different types
Fusiform- Bulging or ballooning of all sides of the aorta; more common
Saccular- Bulging or ballooning of only one side of the aorta
Infrarenal diameter >3cm or >50% increase in size of diameter
85% of cases are infrarenal 
M to F ratio is 4:1
Rupture Risk
<4cm: low risk for rupture
4-5cm: 5 year risk 3-12%
>5cm: 25-41%
Rupture possible at any size, most commonly >5cm
Mortality with rupture: 85-90% 
Fusiform- Bulging or ballooning of all sides of the aorta; more common
Saccular- Bulging or ballooning of only one side of the aorta
85% of cases are infrarenal 
<4cm: low risk for rupture
4-5cm: 5 year risk 3-12%
>5cm: 25-41%
Rupture possible at any size, most commonly >5cm
Mortality with rupture: 85-90% 
Smoking
Risk factor most strongly associated with<unk> 
Also promotes the rate of<unk>  growth
Direct relationship between risk and number of smoking years
Age (prevalence is negligible in age <50yrs)
Family history
Hypertension
Hyperlipidemia
Fluoroquinolone use 
Risk factor most strongly associated with<unk> 
Also promotes the rate of<unk>  growth
Direct relationship between risk and number of smoking years
Abdominal aortic aneurysm
Splenic artery aneurysm
Aortocaval fistula
Superior mesenteric artery syndrome
Acute gastroenteritis
Mesenteric vein thrombosis
Aortoenteric fisulta
Splenic infarction