Subarachnoid Hemorrhage: WFUBMC BestHealth Library

Wake Forest University School of Medicine
Winston-Salem, North Carolina

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Subarachnoid Hemorrhage What is a subarachnoid hemorrhage? A subarachnoid hemorrhage is bleeding onto the surface of the brain, most often caused by a break in a blood vessel at the base of the brain. A blood vessel usually breaks at a weak spot called an aneurysm. When the blood supply to part of the brain is reduced or completely blocked, a stroke may occur. That is, the part of the brain deprived of blood dies and can no longer function. How does it occur? A subarachnoid hemorrhage often occurs without warning and is life threatening. It is most common in the 35- to 65- year-old age group. About 5% of the population has aneurysms. Normal blood pressure can cause the weak spot to balloon and break. High blood pressure strains the weak spot even more. Although an aneurysm can occur in any blood vessel, aneurysms are most commonly found at the base of the brain and in the main artery coming out of the heart. Aneurysms that occur at the base of the brain are usually caused by a defect in an artery that the person has had since birth. In a subarachnoid hemorrhage, the aneurysm most often breaks at the base of the brain and the blood flows into the subarachnoid space, mixing with the fluid that surrounds the brain and spinal cord (cerebrospinal fluid). What are the symptoms? Before rupturing, aneurysms usually produce no symptoms or warning signs. Symptoms that may occur before the aneurysm ruptures include: - headache - weakness on one side of your body - numbness - tingling - speech disturbance - double vision that does not go away. When the aneurysm ruptures, in about half the cases, the person experiences an excruciating headache and falls unconscious almost immediately. In others, a headache develops but the person remains conscious. Some people have no headache and become unconscious quickly without warning. How is it diagnosed? To diagnose a subarachnoid hemorrhage, you will probably have a brain scan. The doctor may do a lumbar puncture to see how much blood has mixed with the cerebrospinal fluid. To determine where the blood vessel broke, the doctor may do an angiogram. During this procedure, dye is injected into your bloodstream and x-rays are taken. The dyed blood vessels then appear on the x-ray film. How is it treated? After a hemorrhage occurs, usually very little can be done to prevent disability or even death. The aim of treatment is to stop the bleeding and damage to the brain and reduce the risk of recurrence. Treatment and monitoring during the 3 weeks immediately following the hemorrhage are important since that is the period when complications and rerupture are most likely to occur. Medication may be prescribed to prevent seizures, and sedatives may be used to aid relaxation. Absolute bedrest is necessary to prevent a rerupture. Sometimes a surgeon can repair a broken blood vessel depending on the location and size of the aneurysm. If unbroken aneurysms are discovered, the doctor may suggest surgery to repair these before they break. Multiple aneurysms are present in as many as 20% of cases. How long will the effects last? If the hemorrhage is large, the person may die immediately. In cases involving smaller hemorrhages the person will regain consciousness, but may be left with some brain damage. Approximately one third of all cases recover completely. How can I take care of myself? Follow your doctor's instructions regarding treatment and frequency of medical visits. Do not smoke, avoid caffeinated beverages, and have your blood pressure checked regularly. How can I help prevent a subarachnoid hemorrhage? Because many of these aneurysms have been present since birth, prevention is difficult. However, you can be aware if you have a family history of strokes and aneurysms and monitor your blood pressure. If an aneurysm is discovered early, the doctor may be able to repair the weak spot and prevent a hemorrhage from occurring. Developed by Clinical Reference Systems. ©1998 Wake Forest University Baptist Medical Center All rights reserved.