70 year old man has abdominal pain with mass in abdomen. Angiography reveals aneurysm of aoa. Most likely cause is -

Ans. is ' b ' i.e., AtherosclerosisClinical presentation of abdominal aoic aneurysm ffects old person (>50 years), male > female.o Most commonly asymptomatic and usually detected on routine examination as palpable, pulsatile nontender mass.o As size increases pain may occur.Complicationso Rupture into the peritoneal cavity and retroperitoneal tissues with massive, potentially fetal hemorrhage. The risk of rupture is directly related to the size of aneurysm.Obstruction of iliac, renal, mesentric or veebral branches due to direct pressure or narrowing of ostia ischemic damage to respective organs.o Impingement on adjacentcent structures e.g. compression of ureter or veebral erosion.o Embolism from atheroma or mural thrombus.