What is the Abdominal Aortic Aneurysm?

Aorta Model With AAA (fixed in acrylic box)

What is the Abdominal Aortic Aneurysm?

Abdominal aortic aneurysm refers to aneurysm-like dilation of the abdominal aorta, usually defined as an aneurysm if the diameter increases by more than 50%. Abdominal aortic aneurysms are more likely to occur in elderly men, with a male to female ratio of 10:3, especially among smokers, who also significantly increase the risk of aneurysm rupture. The vast majority of abdominal aortic aneurysms are lesions below the level of the renal arteries.

1. What is Abdominal Aortic Aneurysm?

Abdominal aortic wall due to injury, destruction and degeneration, leading to loss of arterial wall elasticity. Under the impact of high-pressure blood flow, the diameter of the artery gradually expands, expands, and bulges longitudinally or laterally, forming an abdominal aortic aneurysm.

2. What are the causes of abdominal aortic aneurysm?

Arteriosclerosis is the main cause of abdominal aortic aneurysm. Other reasons are injury, infection, cystic degeneration of the middle layer, and syphilis. Common risk factors for abdominal aortic aneurysm include: smoking, high blood pressure, advanced age, and male sex.

3. What are the clinical manifestations of abdominal aortic aneurysm?

Most patients with abdominal aortic aneurysm are asymptomatic and discovered incidentally during physical examination. The signs are generally a pulsating mass located around the umbilical cord or in the middle and upper abdomen. A small number of patients have abdominal distension, suggesting that the aneurysm has compressed adjacent organs. Sudden increased pain is often a precursor to a ruptured aneurysm or has already ruptured.

1. Pain

It is a common symptom before rupture, mostly located around the umbilical cord and in the middle and upper abdomen. When the aneurysm invades the lumbar spine, there may be pain in the lumbosacral region. If severe pain occurs in the abdomen or waist recently, it often indicates that the aneurysm is on the verge of rupture.

2. Rupture

Patients with acute rupture showed sudden severe pain in the lower back, accompanied by shock, and even died before admission. If it breaks into the retroperitoneum, the hemorrhage is limited and forms a hematoma. Abdominal pain and hemorrhagic shock can last for several hours or days, but the hematoma often ruptures into the peritoneal cavity again and may cause death. The tumor can also break into the inferior vena cava, resulting in aortovenous fistula and heart failure. Occasionally, the tumor can break into the duodenum and cause massive gastrointestinal bleeding.

3. Other serious complications

Acute thrombus can occasionally form in the tumor, and the dislodged thrombus can cause arterial embolism of the lower extremities. Compression of the duodenum can cause intestinal obstruction, and compression and obstruction of the inferior vena cava can cause surrounding edema.