Definition: An abdominal aortic aneurysm (AAA) is a permanent pathological dilation of the abdominal aorta with a diameter over 1.5 times the expected anteroposterior diameter of that segment given the person’s sex and body size Normally the diameter of the abdominal aorta ranges from 1.2–2.4 cm The threshold for diagnosis of AAA is an abdominal aortic diameter of 3.0 cm or greater Epidemiology: More common in males and those over the age of 65. Associated with other vascular aneurysms, particularly popliteal artery aneurysms. Risk Factors: Smoking: Single most important risk factor. Age Family history of AAA Hypertension Hypercholesterolaemia Atherosclerosis Pathophysiology: Debate on the exact cause but atherosclerosis is considered a major contributor. Inflammatory processes weaken the aortic wall, leading to dilatation. Clinical Features: Most are asymptomatic and found incidentally on imaging or examination. Symptoms, if present, include: Abdominal pain or back pain. Pulsatile mass in the abdomen. If ruptured: Severe abdominal pain Shock Collapse Investigations: Abdominal ultrasound: First-line investigation and used for screening. CT angiography: Provides detailed imaging, particularly if surgery is being considered. Management: Small AAAs (<5.5cm in men, <5cm in women): Managed conservatively with regular monitoring and ultrasound scans. Larger or rapidly expanding AAAs: May require surgical intervention either by open repair or endovascular aneurysm repair (EVAR). Other management considerations: Optimise blood pressure control. Stop smoking. Statins and aspirin if indicated. Complications: Rupture: Life-threatening emergency with high mortality. Thrombosis or embolisation from the aneurysm. Prognosis: With early detection and appropriate management, prognosis can be good. Ruptured AAA has a high mortality rate, with many patients dying before reaching the hospital.