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Diagnosis of a migraine headache is based on the history of symptoms, physical examination, and neurological (nerve) tests. The tests are performed to rule out other neurological and cerebrovascular (blood vessels in the brain) conditions, including bleeding within the skull (intracranial hemorrhage), blood clot within the membrane that covers the brain (cerebral venous sinus thrombosis), cerebral stroke or lack of oxygen to the brain (called an infarct), dilated blood vessel in the brain (cerebral aneurysm), excess cerebrospinal fluid in the brain (hydrocephalus), inflammation of the membranes of the brain or spinal cord (meningitis), low level of cerebral spinal fluid (CSF), nasal sinus blockage, postictal headache (occurs after a stroke or seizure), and brain tumor. Computed tomography (CT scan): A computerized axial tomography scan, or CT scan, is an x-ray procedure which combines many x-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body. An intravenous (into the veins) dye is injected into the individual. Then the patient is placed under a large donut-shaped x-ray machine, which takes x-ray images at many different angles around the body. These images are processed by a computer to produce cross-sectional pictures of the body.A CAT scan is a very low-risk procedure. The most common problem is an adverse reaction to intravenous contrast material. Intravenous contrast is usually an iodine-based liquid given in the vein, which makes many organs and structures, such as the brain and blood vessels, much more visible on the CAT scan. There may be resulting itching, a rash, hives, or a feeling of warmth throughout the body. These are usually self-limiting reactions and go away rather quickly. If needed, antihistamines (such as diphenhydramine or Benadryl®) can be given by injection or orally to help relieve the symptoms. A more serious reaction to intravenous contrast is called an anaphylactic reaction. When this occurs, the patient may experience severe hives and/or extreme difficulty in breathing. This reaction is quite rare, but is potentially life-threatening if not treated. Medications taken to reverse this adverse reaction may include corticosteroids (steroids, such as prednisone or Deltasone®), antihistamines, and epinephrine.In migraine patients, a CT scan is performed to rule out an underlying brain abnormality, such as a tumor, when migraines are new or when there is a change in their character or frequency. CT scans may not be as reliable as newer diagnostic techniques, such as magnetic resonance imaging (MRI), but are less expensive. Electroencephalogram (EEG): An electroencephalogram (EEG) records electrical signals originating in the brain (called brain activity). This test is used to detect malfunctions in brain activity, such as seizures or migraines.EEGs are generally performed in a hospital or specialized laboratory. Sometimes the individual having the test will be told to stay up late the night before and to avoid caffeine drinks on the morning of the test. Some EEG tests are made with the patient sitting in a chair. Others are performed with the patient lying down on a couch. The EEG technologist applies small metal disks to several places on the scalp. The hair should be washed on the morning of the test with no additional chemicals, hair sprays, cleansers, cosmetics, or setting gels applied. A special glue, which is washed out afterwards, is used to attach the electrode disks to the scalp. A cap with the wires already attached may be used instead of the glue.During the test, the technologist may ask the person to breathe deeply through the mouth for a short time. This may make the person feel slightly dizzy or produce a numb feeling in the hands or feet, but this goes away when normal breathing is started again. The technologist may shine a blinking light into the person's eyes, or ask him or her to open and close them rapidly a few times. The average EEG test may last 35-40 minutes.Children should be told what to expect during an EEG test, and can be encouraged to "practice" on a doll or stuffed animal beforehand. Lumbar puncture: Lumbar puncture, or spinal tap, is performed to detect infection and determine levels of white blood cells (immune system cells), glucose, and protein in the cerebrospinal fluid. This test involves withdrawing a small amount of fluid from the spinal cord area and examining it under a microscope. The individual lies down on their side on an examination table. There are steps to make sure that the individual does not feel pain during the spinal tap. A topical anesthesia cream (such as Emlon®) on the skin of the back where the spinal tap will be performed (about 30 minutes to one hour before). After the skin is numbed, some doctors also inject liquid anesthesia such as lidocaine into the tissues right under the skin to prevent any further pain. Next, the doctor places a small needle through the skin and then forward through the space between the vertebrae (spine) in the lower back until it enters the space that contains the spinal fluid. When the needle goes into the skin, the individual will not feel sharp pain, only perhaps some pressure. The spinal fluid drips out through the needle into tubes, is collected, and sent to a lab for analysis. This procedure can be uncomfortable for the patient. Side effects can be headaches, pain, infection, or bleeding. Each of these complications are uncommon with the exception of headache, which can appear from hours to up to a day after LP. Headaches occur less frequently when the patient remains lying flat for one to three hours after the procedure. Patients may be given pain medications (such as morphine) or sedatives (such as alprazolam or Xanax®) before and after the procedure. These drugs can cause drowsiness, sedation, and can lead to physical dependence. Magnetic resonance imaging (MRI): An MRI (magnetic resonance imaging) scan is a radiology technique that uses magnetism, radio waves, and a computer to produce images of body structures. The MRI scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The patient may be given a sedative, such as alprazolam (Xanax®), to decrease anxiety and stress associated with the procedure. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. An MRI in patient's with migraines may be performed for a more complete evaluation of the brain, and can visualize blood vessels in the brain to detect aneurysms (tears in blood vessels) and other vascular abnormalities that can be causative agents in migraines. Copyright© 2007 Natural Standard Inc.
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