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Alternative namesBrain bleeding; Brain hemorrhage; Stroke - hemorrhagic
DefinitionHemorrhagic stroke involves bleeding within the brain, damaging adjacent brain tissue.
Causes, incidence, and risk factors
Hemorrhagic stroke occurs when a blood vessel bursts inside the brain. The brain is very sensitive to bleeding and damage can occur very rapidly, either because of the presence of the blood itself, or because the fluid increases pressure on the brain and harms it by pressing it against the skull.
Bleeding irritates the brain tissue, causing swelling (cerebral edema ). The surrounding tissues of the brain resist the expansion of the bleeding, which is finally contained by forming a mass (hematoma). Both swelling and hematoma will compress and displace normal brain tissue.
Most often, hemorrhagic stroke is associated with high blood pressure, which stresses the artery walls until they break.
Another cause of hemorrhagic stroke is an aneurysm. This is a weak spot in an artery wall, which balloons out because of the pressure of the blood circulating inside the affected artery. Eventually, it can burst and cause serious harm. The larger the aneurysm is, the more likely it is to burst. It is unclear why people develop aneurysms, but genes may play a role, since aneurysms run in certain families.
Amyloid protein is also implicated in the brain damage related to Alzheimer's disease, but the difference is that people with Alzheimer´s disease have amyloid accumulatation in the brain tissue instead of in the arteries. Therefore people with Alzheimer´s usually do not develop brain bleeding.
However, in some people, a brain artery may connect directly to a vein, instead of going through the capillaries first. This is called an arterial-venous malformation (AVM). Since blood pressure inside the arteries is much greater that inside the veins, the latter may rupture, causing bleeding into the brain.
Another important brain disease that can cause bleeding is cancer. This is especially true for cancers that spread to the brain from distant organs, such as breast, skin, and thyroid.
About 20% of strokes are hemorrhagic -- but the other 80% are caused by the opposite problem: too little blood reaching an area of the brain, which is usually due to a clot that has blocked a blood vessel. This is called "ischemic stroke." This type of stroke can sometimes lead to a brain hemorrhage because the affected brain tissue softens and this can lead to breaking down of small blood vessels.
Some medications (often used, ironically, to prevent ischemic stroke) prevent clot formation. These work by blocking the production of clotting factors (such as the blood thinner warfarin) or interfering with the function of platelets (such as aspirin). The most common side effects of such medications is bleeding, which may occasionally affect the brain. Controlling bleeding to avoid stroke is a very fine balancing act.
Other drugs that can be associated with brain hemorrhage are cocaine and certain cough remedies, although the mechanism by which they do so is unclear.
SymptomsStroke symptoms are typically of sudden onset and may quickly become worse. The following is a list of possible problems:
Signs and tests
The neurologic exam is almost always abnormal. Patients may look drowsy and confused. Eye examination may show abnormal eye movements, and changes may be seen on retinal examination (examination of the back of the eye with an instrument called ophtalmoscope). Abnormal reflexes may be present. However, these findings are not specific to brain hemorrhage.
The most important test to confirm the presence of a brain hemorrhage is a CT scan, which provides pictures of the brain, and should be obtained without delay. A brain magnetic resonance imaging (MRI) scan can also be obtained later to better understand what caused the bleeding. A conventional angiography (X-rays of the arteries using dye) may be required to demonstrate aneurysms and/or AVM.
Treatment includes life-saving measures, relief of symptoms, repair of the cause of the bleeding , prevention of complications, and start of rehabilitation as soon as possible. Recovery may occur over time as other areas of the brain take over functioning for the damaged areas.
A person having a hemorrhagic stroke may be unable to protect the airway during coughing or sneezing because of impaired consciousness. Saliva or other secretions may go "down the wrong pipe," which is potentially serious and may cause lung problems such as aspiration pneumonia. In order to treat and/or prevent these breathing problems, a tube may need to be placed through the mouth into the trachea to initiate mechanical ventilation.
The blood pressure may be too high or too low in patients with brain hemorrhage. These problems need to be addressed immediately by doctors. In addition, brain bleeding may cause swelling of surrounding brain tissue, and this may require therapy with some drugs called hyperosmotic agents (mannitol, glycerol, and hypertonic saline solutions).
Bedrest may be advised to avoid increasing the pressure in the head (intracranial pressure). This may include avoiding activities such as bending over, straining, lying flat, sudden position changes or similar activities. Stool softeners or laxatives may prevent straining during bowel excretion (straining also causes increased intracranial pressure ).
The goal of surgery for subarachnoid bleeding, for example, is to suppress the chances of a second bleed from any identified aneurysm, which would almost always be fatal. The surgeon has to open up the skin and skull to expose the base of the brain, where the aneurysm is located, and place a clip on it, which prevents future leaking of blood from the affected artery. When surgery is too risky or technically impossible, a coil embolization can be attempted. This procedure consists of threading a special coil into the aneurysm through a catheter inserted in an artery. The coil literally clogs the aneurysm, preventing further leakage of blood.
For other types bleeding, a removal of the hematoma may occasionally be needed, especially when bleeding occurs in the back of the brain. Some physicians are currently investigating whether the injection of a "clot buster" inside the hematoma can facilitate the removal of brain hemorrhages through needles or catheters, therefore allowing less invasive surgery.
One common problem related to brain bleeding is hydrocephalus, which is the accumulation of a water-like fluid within the brain cavities called ventricles. To solve this problem, the fluid may need to be drained with a special procedure called ventriculostomy.
For AVM, different treatments are available, including surgical removal of the AVM network, radiosurgery (using ionizing radiation to reduce the size of the AVM), and intra-arterial embolization ( a procedure in which glue is injected into the AVM to close the connection between arteries and veins).
Recovery time and the need for long-term treatment are highly variable in each case. Physical therapy may benefit some persons. Activity should be encouraged within the physical limitations. Alternative forms of communication such as pictures, verbal cues, demonstration or others may be needed depending on the type and extent of language deficit. Speech therapy, occupational therapy, or other interventions may increase the ability of some persons to function.
Urinary catheterization or bladder or bowel control programs may be required to control incontinence .
Stroke is the third leading cause of death in developed countries. About one-forth of people who have a stroke die as a result of the stroke or its complications, about one-half have long-term disabilities, and about one-forth recover most or all function.
Hemorrhagic stroke is less common but more frequently fatal than ischemic stroke.
Calling your health care provider
Go to the emergency room or call the local emergency number (such as 911) if symptoms of stroke occur. A stroke is a "brain attack," and minutes can make a huge difference in disability and death rates.
Emergency symptoms include seizures or breathing difficulties , loss of consciousness , sudden difficulties with movement or sensation, eating or swallowing difficulties , sudden vision change or loss of vision in one or both eyes, rapid onset of speech changes, and sudden (severe) headache .
Most cases of hemorrhagic stroke are associated with certain risk factors, such as high blood pressure, smoking, or cocaine use. Controlling blood pressure and avoiding smoking and cocaine can reduce the chances of brain bleeding. Surgical correction of vascular abnormalities like aneurysms or AVMs is sometimes advisable to prevent bleeding
Update Date: 8/5/2002Lucas Restrepo, M.D., Department of Neurology, Johns Hopkins Hospital, Baltimore, MD. Review provided by VeriMed Healthcare Network.
Last updated: Tue, 06 Jan 2009 00:20:03 GMT