Q: I read a news article that says Boston Celtics forward Jeff Green will have surgery to repair an aortic aneurysm. What is an aneurysm? Is this condition life-threatening? --James_ee@yahoo.com

MANILA, Philippines — A: An aneurysm is a localized dilation or ballooning-out of a weakened section in the wall of an artery. Arteries are the pipes (called blood vessels) that carry blood from the heart to the different parts of the body. Their wall consists of several layers of tissues that are designed to withstand the pressure that circulates blood exerts on them.

The weakness in the arterial wall that causes an aneurysm can be congenital (i.e. present at birth) or secondary to medical conditions, usually atherosclerosis and hypertension and less frequently trauma and infection such as syphilis. Aneurysms sometimes run in families because there are certain genetic conditions that predispose a person to the disorder.

The most frequently involved arteryin aneurysms is the aorta, the largest artery in the body, which serves as the main blood vessel that carries blood from the heart to the different parts of the body.  Part of the aorta is in the chest and part is in the abdomen. An aneurysm that occurs in the chest portion of the aorta is called a thoracic aortic aneurysm while that which occurs in its abdominal portion is called an abdominal aortic aneurysm.

 Also fairly common sites of aneurysms are the arteries in the brain. Aneurysms in the arteries of the brain are called cerebral aneurysms.

Aneurysms in arteries other than the aorta and the brain arteries are collectively referred to as peripheral aneurysms. They occur rarely.

Aneurysms are dangerous because they can rupture (burst) or dissect. Rupture of an aneurysm causes bleeding inside the body whereas dissection, which refers to a split in the layers of the wall of the artery, can cause bleeding into and along the layers of the artery.  Rupture or dissection of any part of the aorta results in massive bleeding and often, death. Rupture or dissection of a cerebral aneurysm on the other hand, results in a stroke, which is also often fatal.

Peripheral aneurysms do not rupture or dissect as frequently as aortic or cerebral aneurysms, but they can form blood clots that can dislodge, be carried by blood and clog other arteries.

Aneurysms generally grow over a period of years without causing any sign or symptom until they are large enough to press on nearby structures or until they rupture or dissect.

The signs and symptoms of an aneurysm, when they occur, depend on the location. Abdominal aortic aneurysms may present as throbbing in the abdomen or as deep gnawing pain in the back or side of abdomen. Thoracic aortic aneurysms, on the other hand, may manifest as coughing, hoarseness, shortness of breath, or difficulty in swallowing or breathing, while cerebral aneurysm may present as occasional headache, loss of sensation in the face or eye problems.

Rupture or dissection of an aortic aneurysm causes severe pain in the area of rupture, sweaty skin, cold-clammy perspiration and rapid heart rate. Massive bleeding can lead to shock, a condition where the blood pressure drops suddenly, compromising the blood supply to the brain, kidneys and other vital organs. Shock is fatal unless treated immediately.

In cerebral aneurysms, the manifestations of a rupture include severe headache, nausea, visual impairment, vomiting and loss of consciousness.

The management of aneurysms depends on their size. Small aneurysms that are found early (usually accidentally, because the person is being worked up for another condition) are often not treated but simply observed—the person undergoes periodic testing to make sure the aneurysm is not growing.  Aneurysms that are growing quickly together with those that are large and at risk of rupture or dissection are treated by surgery. Aneurysms that have ruptured, on the other hand, need immediate medical and/or surgical treatment in an adequately-equipped hospital.

(Email inquiries on health matters to: medical_notes@yahoo.com)