aneurysms

An aneurysm is a localized, permanent dilation of a blood vessel or heart chamber resulting in a cross-sectional area that is larger than normal. Most aneurysms occur in arteries. True aneurysms involve all layers of the vessel wall, while a false or pseudoaneurysm results from a breach in the vessel wall with contained bleeding.

Aneurysms vary by location. The most clinically important types are cerebral (intracranial) aneurysms and abdominal aortic aneurysms (AAA). Peripheral arterial aneurysms can occur in the femoral, popliteal, or other vessels. Risk factors include atherosclerosis, hypertension, smoking, age, and certain connective tissue disorders. Family history also plays a role.

Symptoms: Many aneurysms do not cause symptoms until they enlarge or rupture. Cerebral aneurysms may present with sudden severe headache, neck stiffness, or neurologic deficits if ruptured. AAAs are often asymptomatic, but large or enlarging aneurysms may cause back or abdominal pain or a pulsatile mass; rupture leads to life-threatening bleeding.

Diagnosis: Imaging is used to detect and monitor aneurysms. AAA is commonly found by ultrasound or CT. Cerebral aneurysms are detected by CT or MRI with angiography. Angiography, CT angiography, or MR angiography can delineate anatomy for planning treatment.

Treatment: Small, stable aneurysms may be monitored with imaging. Larger or expanding aneurysms generally require intervention. Abdominal aortic aneurysms can be repaired with open surgery or endovascular aneurysm repair (EVAR). Cerebral aneurysms may be treated with clipping or endovascular coiling, with or without flow-diverting devices. The choice depends on anatomy and patient factors.

Prognosis and prevention: Rupture of a brain aneurysm or of a large abdominal aneurysm carries substantial mortality and morbidity. Prevention centers on controlling risk factors, especially smoking and hypertension, and appropriate surveillance for known aneurysms.