Thyroid & Adrenal
Formation of aortic aneurysm results from all of the following except:
|A||Thickening of the adventitia|
|B||Change in structure of collagen & elastin within the vessel wall|
|C||Increased collagenase activity|
|D||Loss of elastin from media|
a. Aneurysm formation is not simply secondary to tension relived to passive dilation.
b. It is a complex process that involves remodeling in the structure of collagen & elastin with the vessel wall.
c. This is associated with activation of inflammatory mediators, especially in patients with atherosclerotic infection or autoimmune disorders.
d. Adventitial thickening compensates for weakness of the media until increased collagenase activity leads to degradation of the adventitial layer.
e. Trauma is an important and infrequent cause of the aneurysm.
f. The thoracic aneurysms are classified in five groups.
g. 1.Traumatic usually occurring distal to left subclavian artery 2. Descending thoracic aorta 3. Thoracoabdominal.