"At this point Bret remains in ICU in critical condition. He is under 24 hour doctors care and supervision. We are hopeful that further tests will locate the source of the bleeding, which has still not been located. As we all know Bret is a fighter and we are hopeful that once all is complete the slurred speech, blurred vision and dizziness, etc., will be eliminated and all functions will return to normal," read the post on BretMichaels.com.
It also gave a shout out to the fans, who have expressed concern and support since news of Michaels's brain hemorrhage broke Friday. "Everyone at Michaels Entertainment would like to thank all fans and friends for their continued thoughts and prayers through this difficult time," it said.
Explaining the "Very Serious" Hemorrhage
Typically caused when a previously undetected aneurysm, or enlarged artery in the brain, ruptures suddenly, a subarachnoid hemorrhage – which refers to the area of the brain where the bleeding occurs – "can happen to anybody at anytime, and that's why it's scary," Dr. Keith Siller of New York University's Comprehensive Stroke Care Center tells PEOPLE.
Such hemorrhages are fatal in half of all cases, and 15% to 20% of people who suffer from them never even make it to the hospital.
Neither Michaels's history of diabetes nor his recent appendectomy would be considered triggers for this type of brain hemorrhage, says Dr. Siller. Likewise, his onstage injury at the Tony Awards last year – in which Michaels was hit with an errant piece of scenery – could not have caused a hemorrhage nearly 11 months later.
The most significant risk factor for triggering this kind of rupture is smoking, says Dr. Siller. The aneurysm itself, which occurs in less than 2% of the population, is "something most people are just born with. Most people have no clue that they have this. People usually find out when they have a hemorrhage. In most cases, that is the cause. It's something people have silently."
With Michaels's doctors still unable to locate the source of the bleeding, "the goal here is to find the aneurysm," says Dr. Siller. "There are a small percentage of subarachnoid hemorrhages where sometimes the aneurysm has already ruptured and you can't find it. Or it's so small, and all this blood's still sitting there, and it hides the aneurysm from being seen by an angiogram."
"If you don't see the aneurysm, you're kind of stuck. You have to just repeat the angiogram and see whether some blood becomes visible."
If located, doctors typically treat such hemorrhages either with surgery, in which the source of the leak is clipped, or with "coiling," in which slivers of metal are inserted through a catheter in order to clot the blood.
"These are very serious hemorrhages," says Dr. Siller, adding that Michaels' prognosis depends on his condition at the time he was admitted to the hospital. "The better condition you are when you get to the hospital – in other words, if you're awake, talking – if you're conscious, those people have a very good prognosis that they can come out of this okay."
"The people who come in comatose, or don't have reflexes, they're already in very bad shape," he says. "They're not the kind of person you can take into the operating room."
Like Michaels, most patients' first tip-off to this kind of hemorrhage is an excruciating headache – "the worst headache of your life," says Dr. Siller, who stresses the importance of seeking emergency medical care in that situation. "A lot of people have these awful headaches, and they don't come to the hospital in time," says Dr. Siller. "They're losing valuable time."