Abdominal Aortic Aneurysm
Also written as AAA.
Lactic acidosis - absent femoral pulses indicate vascular insufficiency (likely acute mesenteric ischemia or ruptured abdominal aortic aneurysm)
What our notes say
- Lactic acidosis - absent femoral pulses indicate vascular insufficiency (likely acute mesenteric ischemia or ruptured abdominal aortic aneurysm) (Chemical Pathology Sem 1)
- Alternative diagnosis: Ruptured abdominal aortic aneurysm with bowel ischemia (Chemical Pathology Sem 1)
Study material on Abdominal Aortic Aneurysm
Practice questions on Abdominal Aortic Aneurysm
A 72-year-old male with longstanding hypertension is found to have a dilated abdominal aorta measuring 6.2 cm on ultrasound. Which layer of the aortic wall is MOST affected in abdominal aortic aneurysm (AAA), and what is the key pathological mechanism?
- Intima - atherosclerotic plaque erodes into the media
- Media - destruction of elastin and collagen by matrix metalloproteinases (MMPs)
- Adventitia - inflammatory infiltrate causing external compression
- Intima - fibromuscular hyperplasia narrows the lumen
- Media - cystic medial degeneration with mucoid deposits ✅ Answer: B
Answer: A. Abdominal aortic aneurysms primarily involve the media, where chronic inflammation and enzymatic degradation (especially by MMPs) lead to the destruction of elastin and collagen, weakening the vessel wall.