Things have gone from bad to worse for rock star and Celebrity Apprentice contestant, Bret Michaels. He was hospitalized for appendicitis, and underwent an emergency appendectomy, about 10 days ago. Four days later, although the surgery had gone well, Michaels was placed in a rehab facility that specializes in diabetics, as Michaels is a Type 1 (insulin-dependent) diabetic. Now his publicist reports that the 47 yr. old Michaels was rushed to an intensive care unit (ICU) after suffering a massive subarachnoid hemorrhage, or bleeding at the base of his brain stem. He is in critical condition. People magazine reports: “After several CAT scans, MRIs and an angiogram, [doctors] decided to keep Michaels in the ICU and are running several tests to determine the cause. [It] will be touch and go for the next few days while he is under intense observation.”
The brain is covered by three layers of membrane, called the meninges. The outer layer which is closest to the inside of the skull, is a thick,fibrous membrane called the dura mater. The delicate, spiderweb-like (hence the name) arachnoid membrane lies beneath the dura and surrounds the brain and spinal cord. Unlike the third layer, the pia mater- which is in contact with the brain surface, the arachnoid membrane does not dip down into the folds of the brain, and is separated from the pia mater by the subarachnoid space.
The brain floats on a liquid cushion of cerebrospinal fluid (CSF) within the skull and fills the subarachnoid space. This acts in effect to reduce the weight of the brain from some 1000 g down to about 50 g, and also protects the brain from knocks on the head. However, since the brain can move within the CSF, it can be damaged on the opposite side by a sudden deceleration such as in a car accident (called a contra coup injury).
A sub-arachnoid hemorrhage is bleeding that occurs into the sub-arachnoid space between the arachnoid and pia mater. In general, head trauma is the most common cause, but traumatic subarachnoid hemorrhage is usually considered a separate disorder. Spontaneous (primary) subarachnoid hemorrhage usually results from ruptured aneurysms. It is the cause in about 85% of patients. Other causes include bleeding from an arteriovenous malformation (AVM), bleeding disorder, use of blood thinners, or unknown causes (idiopathic).
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”. Other symptoms include a sudden or decreased consciousness and alertness, difficulty with motion or sensation, stiff neck, seizures, or vision problems. Sub-arachnoid hemorrhage is considered a form of hemorrhagic stroke. Blood in the sub-arachnoid space causes irritation to the meninges which can increase the pressure inside the skull for days or a few weeks.
A delayed but serious complication of subarachnoid hemorrhage is hydrocephalus, in which the excessive buildup of cerebrospinal fluid in the skull dilates fluid pathways called ventricles that can swell and press on the brain tissue. Another delayed complication is vasospasm, in which other blood vessels in the brain contract and limit blood flow to vital areas of the brain. This reduced blood flow can cause stroke or tissue damage.
The goals of treatment is the preservation of life, repair the cause of bleeding, relieve symptoms, and prevent complications such as permanent brain damage (stroke). If the hemorrhage is due to an injury, surgery is done only to remove large collections of blood or to relieve pressure on the brain. If the hemorrhage is due to the rupture of an aneurysm, surgery is needed to repair it. If the patient is critically ill, surgery may have to wait until the person is more stable.
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