Q. Can you please explain the difference between a brain aneurysm, a stroke and a cerebral hemorrhage? My mother, sister and aunt have all died from these and I wonder if they aren't really all the same thing.
A. The three conditions you list are all due to problems with blood vessels in and around the brain. But they are not exactly the same.
An aneurysm is a bulging or ballooning out of a weak place on the wall of blood vessel, usually an artery. This ballooned-out area is weaker than surrounding wall lining and more likely to burst, causing a hemorrhage or leakage of blood.
Aneurysms usually occur in the aorta, the largest artery in the body, but they also frequently occur in arteries to the brain. If one of these intracranial or cerebral artery aneurysms bursts, brain hemorrhage is the result.
The weakness that causes the bulge and subsequent hemorrhage may be caused by many conditions. Atherosclerosis -- hardening of the arteries from fatty buildup -- is a common cause of aneurysm formation. High blood pressure and cigarette smoking increase the risk of atherosclerosis.
In addition, traumatic injury, congenital defect and bacterial or fungal infection can all cause a weakness in the walls of arteries.
Most of the time before an aneurysm hemorrhages, there are no symptoms. However, some symptoms may be noticed if the aneurysm is large enough to press against other organs or tissues.
For example, intracranial aneurysms of a sufficient size can cause headache before rupture. Sometimes, a person may experience a small amount of leaking just before major cranial hemorrhage, which can also result in headaches.
Tests such as X-rays, ultrasound, CT scans and MRIs can help detect aneurysms. Analysis of the results of these tests can help the doctor determine whether to recommend surgery or, if the aneurysm is small enough, to suggest close follow-up. Of course, if the aneurysm hemorrhages, emergency measures need to be taken.
Stroke is the death of or damage to brain cells from lack of oxygen, caused by disruption of blood flow to the brain.
Most of the time, this disruption is the result of either blockage of a cranial artery or hemorrhage from it. Blockage is more common and is similar in effect to a heart attack, in which the heart's arteries (coronary arteries) are blocked.
A stroke can be caused by a blood vessel that hemorrhages. This in turn can be caused by a burst aneurysm, trauma or disease.
In rare cases of stroke, blood flow to the brain is normal, but the oxygen content in the blood is low, such as with carbon monoxide poisoning and severe anemia.
The effects of a stroke are largely determined by which area of the brain was cut off from blood and oxygen and how long the deficit lasts.
Insufficient blood supply to a part of the brain for only a short period of time is called a transient ischemic attack (TIA or ministroke). TIAs are often warning signs of strokes to come.
So, in summary, a stroke can be caused by, among other things, a cerebral hemorrhage, which can be caused by, among other things, an aneurysm.
Update on stress and illness: People under increased stress have higher rates of illness. And it's been jokingly said that it's all in the head. But a recent study shows that some of it is in the blood. A report in the Journal of Psychosomatic Medicine about highly stressed caregivers indicates that those people under the greatest amount of stress have less than half the number of two critical types of disease-fighting white blood cells. If you are or know someone who is carrying a heavy burden of caring for someone with a chronic illness, I hope that friends and family, as well as professional help, can be found to relieve some of the stress and resulting illnesses.
Write to Dr. Douma in care of the Chicago Tribune, Room 400, 435 N. Michigan Ave., Chicago, IL 60611.