Aneurysm
An aneurysm (or aneurism) is a localized dilation or ballooning of a blood vessel. Aneurysms most commonly occur in the arteries at the base of the brain (the circle of Willis) and in the aorta (the main artery coming out of the heart) - this is an aortic aneurysm. The layer of the artery that is in direct contect with the flow of blood is the tunica intima, commonly called the intima. This layer is made up of mainly endothelial cells. Just deep to this layer is the tunica media, known as the media. This "middle layer" is made up of smooth muscle cells and elastic tissue. The outermost layer (furthest from the flow of blood) is known as the tunica adventitia or the adventitia. This layer is composed of connective tissue.
Aneurysms shapes
- Saccular
- Fusiform
Arteries affected
- abdominal aorta Most Aneurysms (95%) arise distal to the origin of the renal arteries. The cause is mostly atherosclerosis
- Thoracic aorta
Aneurysms can be broken down into two groups: true aneurysms and false aneurysms. A true aneurysm involves an outpouching of all three layers of a blood vessel: the intima , the media, and the adventitia. True aneurysms can be due to congenital malformations, infections, or hypertension.
While most aneurysms occur in an isolated form, berry aneurysms of the anterior communicating artery of the circle of Willis is associated with autosomal dominant polycystic kidney disease (ADPKD).
The third stage of syphilis also manifests as aneurysm of the aorta, which is due to loss of the vasa vasorum in the tunica adventitia.
A false aneurysm, also known as a pseudoaneurysm, involves an outpouching of only the intima. Pseudoaneurysms can be due to trauma involving the intima of the blood vessel. Pseudoaneurysms are a known complication of percutaneous arterial procedures.
More inclusively, aneurysm is known as ectasia, ectasis, and ectasy. For example,
- Atelectasis is the dilation of the lungs of newborns
- Bronchiectasis is of bronchial tubes
- Phlebectasia is of vein
- Sialectasis is of the ducts of the salivary glands, especially the parotids
- Telangiectasis is of small blood vessels
- Trichangiectasia is of capillaries
management
Ultraound, MRI, CT to define and localize Aneurysms. Large Aneurysms are surgically repaired