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
- true aneurysm
- false aneurysm (or pseudoaneurysm)
Causes
- congenital
- atherosclerosis
- hypertension
- vasculitis
- hereditary connective tissue disorders
- fibromuscular dysplasia
- infection: mycotic aneurysm, syphilis (luetic aneurysm)
- 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:
- saccular aneurysm: eccentric, involving only a portion of the circumference of the vessel wall
- fusiform aneurysm: concentric, involving full circumference of the vessel wall
Occasionally a 3rd type, serpentine aneurysm has been classified as a separate entity 3.
Complications
- rupture
- distal thromboembolism
- pressure effects