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Subarachnoid hemorrhageDefinition Subarachnoid hemorrhage is bleeding between the middle membrane covering of the brain and the brain itself. Specifically it occurs within the cerebrospinal fluid-filled spaces surrounding the brain (also known as the subarachnoid space). Patients with subarachnoid hemorrhage usually complain of the "the worst headache of their lives." Causes, incidence, and risk factors Subarachnoid hemorrhage occurs in approximately 1 out of 10,000 people. About 5 to 10% of strokes are caused by subarachnoid hemorrhage. It is most common in people 20 to 60 years old. It is slightly more common in women than men. The most common cause of any form of subarachnoid hemorrhage is trauma. The most common cause of subarachnoid hemorrhage in young adults is a ruptured cerebral aneurysm. A small percentage of subarachnoid hemorrhages have a nonaneurysmal pattern to them. They occur spontaneously, and are usually localized to the area in the brain called the perimesencephalic cisterns. The usual outcome for this type of hemorrhage is excellent. Unlike the majority of hemorrhages that are caused by arterial ruptures, this type is thought to be caused by a ruptured vein or capillary. Subarachnoid hemorrhage occurs when there is bleeding into the space between the brain and the arachnoid membrane (the middle membrane covering the brain). This may occur from a ruptured cerebral aneurysm or arteriovenous malformation, but some result from unidentified causes. Risks include: disorders associated with aneurysm or weakened blood vessels, including a history of polycystic kidney disease, fibromuscular dysplasia (FMD), other connective tissue disorders, aneurysms in other blood vessels, high blood pressure, and smoking. The disorder may cause permanent brain damage from ischemia (loss of blood flow) or from the presence of blood in and around the tissues of the brain. Symptoms
Additional symptoms that may be associated with this disease:
Signs and tests About 30% of patients with SAH are misdiagnosed at first. If subarachnoid hemorrhage is suspected, a computed tomography (CT) scan (without dye contrast) of the head should be immediately performed. In some cases, the head CT scan may be normal, especially if there has only been a small bleed. If the CT scan is normal, a lumbar puncture (spinal tap ) must be performed. Patients with SAH will have blood in their spinal fluid. Cerebral angiography of blood vessels of the brain may show small aneurysms or other vascular problems. This test can pinpoint the exact location of the bleed. A physicial exam may reveal a stiff neck due to irritated meninges (the tissues covering the brain). Movement of the neck may be resisted in all but deeply comatose people. There may also be signs of decreased nerve and brain function (focal neurologic deficit ). An eye exam may also reveal bleeding in the brain. Decreased eye movements can indicate damage to the 3rd or 6th cranial nerve. SAH may also alter the results of CPK isoenzymes. Treatment Treatment goals include lifesaving measures, relief of symptoms, repair of the cause of the bleeding, and prevention of complications. Treatment for coma or decreased mental status may be required, including positioning, airway protection, and life support, and placement of a drain (small plastic tube into the fluid-filled spaces within the brain—ventricles—to relieve intracranial pressure). If a person is conscious, strict bedrest may be advised, accompanied by measures to avoid increases in intracranial pressure (pressure in the head). This may include avoiding activities such as bending over, straining, sudden position changes, or similar activities. Stool softeners or laxatives may prevent straining during bowel movements. Pain killers and anti-anxiety medications may be used to relieve headache and reduce intracranial pressure. Antihypertensive medications may be used to moderately reduce blood pressure if it is very high. Phenytoin or other medications may be used to prevent or treat seizures. Nimodipine (a calcium channel blocker) is used to prevent vasospasm (spasm of a blood vessel). Treatment is usually required, which may be either via a craniotomy (opening a hole in the skull) and clipping of the aneurysm (placing a metal clip across the base of the aneurysm so as to separate it from the circulation), or endovascular coiling (placing platinum coils within the aneurysm from the inside of the blood vessel itself). Surgical removal of large collections of blood may also be needed. Expectations (prognosis) How well a patient with SAH does depends on the locaiton and extent of the bleeding, as well as any complications. Complete recovery can occur after treatment, but death may occur in some cases with or without treatment. Complications
Calling your health care provider Go to the emergency room or call the local emergency number (such as 911) if symptoms of subarachnoid hemorrhage are present. Emergency symptoms include seizures or breathing difficulties; loss of consciousness; difficulties with speech, vision, movement, or sensation; and eating or swallowing difficulties. Prevention Identification and successful treatment of an incidentally found aneurysm would prevent subarachnoid hemorrhage. References Kirmani JF, Alkawi A, Ahmed S, et al. Endovascular treatment of subarachnoid hemorrhage. Neurol Res. 2005;27 Suppl 1:103-7. Edlow JA. Diagnosis of subarachnoid hemorrhage. Neurocrit Care. 2005;2(2):99-109. Bird S. Failure to diagnose: subarachnoid haemorrhage. Aust Fam Physician. 2005 Aug;34(8):682-3. Marx J. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th ed. St. Louis, Mo: Mosby; 2002:2362-2363. Illustrations
Page Content: Hemorrhage - subarachnoid ; subarachnoid hemorrhage; subarachnoid hemorrhage symptom; subarachnoid hemorrhage treatment |
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