Aneurysm

Aneurysms are focal abnormal dilatation of a blood vessel. They typically occur in arteries, venous aneurysms are rare. Aneurysms may also occur in the heart.

Pathology

Pathological types

1. true aneurysm
2. false aneurysm (or pseudoaneurysm)

Causes

Atherosclerotic

• atherosclerosis

Non-atherosclerotic

• congenital
• hypertension
• vasculitis
  • fibromuscular dysplasia
  • infection: mycotic aneurysm, syphilis (luetic aneurysm)
• hereditary connective tissue disorders
  • Marfan syndrome
  • Ehlers-Danlos syndrome
• trauma
• iatrogenic
• myocardial infarction: may cause left a ventricular aneurysm
• flow related (in cerebral AVM, contralateral ICA occlusion etc)

Morphology

Morphologically there are two main types of aneurysms. The morphology is not specific for any cause:

1. saccular aneurysm: eccentric, involving only a portion of the circumference of the vessel wall. ("Berry" aneurysm).
2. fusiform aneurysm: concentric, involving full circumference of the vessel wall

Occasionally a 3^rd type, serpentine aneurysm has been classified as a separate entity ³.

Complications

• rupture
• distal thromboembolism
• pressure effects

See also

• thoracic aortic aneurysm
• abdominal aortic aneurysm
• popliteal artery aneurysm
• cerebral berry aneurysm
• coronary artery aneurysm
• splenic artery aneurysm
• celiac artery aneurysm
• mycotic aneurysm