"Generally speaking, subarachnoid hemorrhage that is not the result of a ruptured brain aneurysm carries a much more favorable prognosis," said Dr. Vivek Deshmukh, director of Cerebrovascular and Endovascular Neurosurgery at George Washington University in Washington, D.C. "In Mr. Michaels' case, the fact that he is awake and talking is a very good sign.
"The report that Mr. Michaels is awake enough to respond to questions means that he is not at the end of the scale that has the worst outcome," said Dr. Alan Hoffer, director of Neurotrauma at the University Hospitals Case Medical Center in Cleveland, Ohio. But, he added, "The presence of cranial nerve deficits, implied by his difficulty with vision and speech, means that he is likely in the middle of the scale."
The prognosis could be much worse if an aneurysm is, indeed, to blame. Dr. Nicholas Bambakidis, director of Cerebrovascular and Skull Base Surgery at University Hospitals Case Medical Center, said that many aneurysm patients suffer irreversible brain damage as a result of the hemorrhage itself.
"In cases in which there is no neurological damage initially, then patients must face the risk of the treatment, which consists of surgery to repair the aneurysm by closing it off such that blood no longer enters it," Bambakidis said. "If all goes well, patients then face a risk of stroke due to spasm in their normal blood vessels, which is caused by some type of reaction to the initial hemorrhage we do not fully understand , which and can occur up to three weeks after the bleeding.
"Though we do have medications and treatments aimed at reducing this risk ... they are not always effective and up to 20 percent of patients can have a serious stroke despite our best efforts."
Dr. Carmelo Graffagnino, director of the Duke Neurosciences Critical Care Unit in Durham, N.C., said that aneurysm or not, the initial severity of the bleed is also an important factor.
"The likelihood of further short term complications depends on how much blood was released during the subarachnoid bleed," Graffagnino said. He said that the fact that Michaels is a diabetic could make his care more complex and increase the likelihood he could experience "complications and slowed recovery."
The latest medical woes for Michaels came just days after an emergency appendectomy he received after falling ill before a concert April 11.
Besides his active performing career, Michaels can be seen each week as a top contender on Donald Trump's NBC reality show "The Celebrity Apprentice," competing against singer Cyndi Lauper and media maven Sharon Osbourne, to name a few of the remaining competitors. He previously starred in VH1's "Rock of Love With Bret Michaels."
Sheila Marikar contributed to this report.