An aortic aneurysm is an enlargement (dilatation) of the aorta to greater than 1.5 times normal size. Typically, there are no symptoms except when the aneurysm dissects or ruptures, which causes sudden, severe pain in the abdomen and lower back.
The cause remains an area of active research. Known causes include trauma, infection, and inflammatory disorders. Risk factors include cigarette smoking, heavy alcohol consumption, advanced age, harmful patterns of high cholesterol in the blood, high blood pressure, and coronary artery disease. The pathophysiology of the disease is related to an initial arterial insult causing a cascade of inflammation and extracellular matrix protein breakdown by proteinases leading to arterial wall weakening. They are most commonly located in the abdominal aorta, but can also be located in the thoracic aorta.