The next few days will be critical to [artist id="500964"]Bret Michaels'[/artist] potential recovery from a [article id="1637715"]brain hemorrhage[/article] he suffered late Thursday, according to one of the nation's leading stroke experts.

"He had a subarachnoid hemorrhage, which is not the most common type of stroke," said Dr. Joseph Broderick, a member of the American Academy of Neurology and chair of the University of Cincinnati Neurology Department.

Broderick, a specialist in the treatment of acute stroke and the genetics of hemorrhagic stroke, is not treating Michaels and does not have first-hand knowledge of the singer's case, but said that based on the information made public so far, the case is very serious but could be survivable. (An unnamed source told People that Michaels suffered a subarachnoid hemorrhage, or bleeding at the base of the skull, and on Friday, a rep for the singer confirmed that People's report was correct.)

"This kind only happens in about 5 percent of cases, where you have bleeding from the artery at the base of the brain, a kind of explosion of blood around the base of the brain, and it can be very serious," Broderick told MTV News, noting that 30 percent of patients die from this type of injury within the first month. However, many are able to survive and live relatively normal lives afterwards.

He said the major risk factors for the kind of stroke that Michaels suffered are smoking and drug use, specifically cocaine, but it is unclear whether Michael is or was a heavy cigarette smoker or cocaine user.

As of press time, [article id="1637746"]Michaels, 47, remains in an intensive care unit[/article] under 24-hour surveillance, and further testing was planned to find the source of the bleeding, according to his website.

The singer is reportedly suffering from slurred speech, blurred vision and dizziness as a result of the hemorrhage, all normal side effects of the traumatic incident according to Broderick. "These are pretty common things you'd see after this type of stroke and it can get worse," he said about the blurry vision and speech difficulty. "The arteries can go into spasm after four or five days and get worse over the next week or two."

Though those spasms can cause the other, more typical type of stroke, an ischemic one where blood supply to the brain is interrupted by a blocked artery, Broderick said doctors should have a better sense of Michaels' chance of recovery over the next two weeks or so. "Patients typically die within the first couple of days or a week from this kind of stroke," he said.

Michaels, who was diagnosed with diabetes as a child, had an emergency appendectomy earlier this month, an event he called a "wake-up call to be a little bit more diligent on keeping control of my health" in a blog post. Broderick said it's not clear if the diabetes could have any relationship to the hemorrhage, but lingering inflammation from the appendectomy could have links to the brain injury.

In 10-15 percent of cases, doctors are unable to find the source of the bleeding in cases such as Michaels', but Broderick said if they do, then cutting it off is relatively straightforward. "If it's an aneurysm, they coil it or put a clip on it where it comes off the blood vessel and isolate it," he said. "If you can't find the cause, then you wait for the effects to wear off and you don't really do anything but observe."

Share your well wishes for Bret Michaels in the comments below.