06/24/2010 05:12 am ET Updated May 25, 2011

Bret Michaels: Brain Hemorrhage Explained -- What It Is And How Serious

Bret Michaels has been rushed to an LA hospital with a massive subarachnoid hemorrhage -- which is bleeding in the brain and apparently Michaels' publicist has confirmed to ABC that there is bleeding at the base of his brain stem. consulted Dr. Dexter Sun, a neurologist at New York Presbyterian Cornell-Weill Medical College, to find out what this type of brain hemorrhage is, and what the prognosis can be.

"If this is massive and especially if the brain stem is involved, this is usually very serious," says Dr. Sun. "If the hemorrhage was minor, usually it would resolve on it's own. However, if it's massive, the most common cause would be a cerebral aneurysm."

Dr. Sun explained that if Michaels' hemorrhage was caused by an aneurysm, he would need a very skillful brain surgeon to operate and "clip" the aneurysm to stop it.

If the hemorrhage is not caused by an aneurysm, it could be caused by a brain injury or by a blood clotting factor defect . If caused by a blood clotting factor defect, Michaels would be transfused with blood clotting factor to stop the bleeding.

It is very important to control the severe headache pain and to decrease pressure in the brain, according to Dr. Sun.

Severe headache pain can increase pressure in the brain ,which can then increase the hemorrhage and if the brain swells, it can be very dangerous if it pushes down on the brain stem, explains Dr. Sun."The brain stem truly is the center of life -- it's the center of breathing." Severe pressure on the brain stem can cause "'brain herniation' which could cause a a coma."

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