(Please see the comments section for updates on this story. Bret Michaels has been released from Barrow Neurological Institute at St. Joseph's Hospital and Medical Center in Phoenix, and is now in an outpatient rehabilitation program.)

Rock singer and reality TV personality Bret Michaels remains critically ill after suffering a massive brain hemorrhage, prompting some to wonder what causes this condition as well as the prognosis for recovery.

The 47-year-old Michaels appeared on the reality show “Celebrity Apprentice” and was the lead singer for the 80’s rock band “Poison.” He was rushed to a hospital on Thursday, April 22 after complaining of a severe headache. Doctors diagnosed a massive subarachnoid hemorrhage. On Sunday, April 25 his doctors said he was in critical condition and is conscious and talking with slurred speech.

What exactly is a subarachnoid hemorrhage? This means a person is bleeding in the area between the brain and the thin tissues that cover the brain. This area is called the subarachnoid space. Another way to describe this condition is as a type of stroke that occurs when a blood vessel ruptures and blood quickly fills the area immediately surrounding the brain and spinal cord - the subarachnoid space. This space contains cerebrospinal fluid, which cushions and bathes the brain and spinal cord. This life-threatening condition, which requires emergency medical care, may increase the pressure around the brain and can interfere with its function.

About 30,000 Americans suffer from a subarachnoid hemorrhage every year, with most patients between the ages of 35 and 65. It’s usually caused by:
• Serious head injury
• Rupture of cerebral aneurysms and other blood vessel deformities at the base of the brain (spontaneous subarachnoid hemorrhage); such defects are usually present since birth.
• Bleeding disorders
• Illicit drug use ( especially cocaine and amphetamines)

The main symptom is a severe headache that starts suddenly and is often worse near the back of the head. Patients often describe it as the "worst headache ever" and unlike any other type of headache pain. The headache may start after a popping or snapping feeling in the head.

Other symptoms include the following:
• Brief loss of consciousness
• Seizures
• Nausea
• Weakness on one side of the body
• Unexplained numbness or tingling
• Slurred speech or other speech disturbance
• Visions problems, such as double vision, blind spots, or temporary vision loss on one side
• Stiff neck or shoulder pain
• Confusion

Subarachnoid hemorrhage is a serious condition requiring initial treatment in the intensive care unit. The treatment goal is to stop the bleeding, limit damage to the brain, and reduce the risk of recurrence. If bleeding results from a cerebral aneurysm, a surgeon will usually attempt to stop it using various techniques. Patients receive medications to insure proper blood flow to the rest of the brain and must remain at absolute bed rest to prevent additional bleeding. Once the situation is stabilized, patients undertake a vigorous rehabilitation program. Despite treatment, approximately 25 - 30 per cent of patients with this condition die.

For those who recover, there are often severe physical and emotional challenges. The Brain Aneurysm Foundation at http://www.bafound.org/ offers resources for survivors, caregivers, families and friends.

Michaels was diagnosed with diabetes as a child and had an emergency appendectomy in early April. In a blog entry, he called it a "wake-up call to be a little bit more diligent on keeping control of my health."

His publicists issued a statement on Sunday, April 25 that said he was still under 24-hour supervision and in critical condition. The statement said his doctors were trying to locate the source of the bleeding. "Bret is a fighter and we are hopeful that once all is complete, the slurred speech, blurred vision and dizziness will be eliminated and all functions will return to normal," the statement added.

About the author: Pat Elliott is a journalist and blogger who has written about health issues for more than 20 years. She is also a cancer survivor who coaches people on how to manage their transition and take control of their new future.