The aorta, the main artery carrying blood to the body, runs through the middle of the abdomen. An abdominal aortic aneurysm (AAA) results from a weak spot in the abdominal segment of the aorta that causes it to bulge. Rupture of the bulge is a life-threatening emergency because of internal bleeding. Detection of an abdominal aortic aneurysm often occurs incidentally, as a result of abdominal imaging for another condition, because AAAs usually do not cause any symptoms until they burst, according to the Mayo Clinic.
Sometimes an abdominal aortic aneurysm might cause a throbbing feeling in the abdomen, often near the navel. You might notice it, or your doctor might be able to feel a throbbing mass when he palpates your abdomen. Small abdominal aortic aneurysms are difficult to feel and even a large abdominal aortic aneurysm might not be detectable this way, especially in obese patients. According to the Merck Manual, detection of a throbbing mass in the artery correctly predicts an abdominal aortic aneurysm in about 40 percent of cases.
Using a stethoscope, sometimes a doctor can hear a telltale sign of the abnormal blood flow through an abdominal aortic aneurysm. Instead of the normal smooth whooshing sound of steady, even blood flow, the weakened part of the aorta allows the stream of the blood flow to spread out. As the blood stream narrows again past the aneurysm it causes a rushing sound called a systolic bruit.
Sometimes an abdominal aortic aneurysm causes pain in the front or sides of your abdomen or your lower back (lumbosacral region). The National Heart, Lung and Blood Institute describes the pain of an abdominal aortic aneurysm as deep, steady and gnawing and the Merck Manual refers to a boring, visceral pain. The pain can last for hours to days. When the abdominal aortic aneurysm grows rapidly, leaks blood or is about to burst, your abdomen might feel tender.
Symptoms of Rupture
Rupture of an abdominal aortic aneurysm can occur spontaneously, or it can follow a blow to the abdomen or strain from lifting a heavy object. The rupture causes massive internal bleeding and symptoms of shock and is rapidly fatal without emergency surgery. Sudden, severe pain in the abdomen or lower back signals the rupture. The patient might feel light-headed, dizzy and nauseated or might vomit and have clammy, sweaty skin--all symptoms of the rapid fall in blood pressure. The victim's pulse and heart rate race (tachycardia), especially when he stands up, and he might lose consciousness. The internal bleeding might cause other signs of shock including shallow breathing and a bluish discoloration of the lips and fingernails.