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ABDOMINAL AORTIC ANEURYSM

 

TYPE;

Abdominal aortic aneurysms (AAAs) are true aneurysms

EPIDEMIOLOGY

 They classically occur in male smokers older than 50 years

POSITION OF ANEURYSM

 They are positioned below the renal arteries and above the iliac bifurcation.

CRITICAL AREAS AFFECTED; IT AFFECTS;

  • the common iliac arteries
  • aortic arch
  • descending thoracic aorta

PATHOGENESIS

 Pathogenesis involves medial SMC loss and increased matrix degradation by MMP.

HISTOLOGY

 histology reveals severe complex atherosclerosis with markedly attenuated media. Due to the aneurysmal dilation and abnormal vascular flow, the lumen typically contains a laminated, poorly organized mural thrombus.

COMPLICATIONS;

 Complications include

  • occlusion of a branch vessel
  • atheroembolism, compression of adjacent structures
  • Risk of rupture increases with the maximal diameter of the AAA

INFLAMMATORY AAA; Inflammatory AAA is a variant of AAA characterized by dense periaortic fibrosis and an exuberant transmural lymphoplasmacytic infiltrate.

MYCOTIC AAA; Mycotic AAAs occur when circulating microorganisms (as in bacteremia from a Salmonella gastroenteritis) seed the aneurysm wall or the associated thrombus; the resulting suppuration accelerates the medial destruction and may lead to rapid dilation and rupture.

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