30 Apr 2009
A migraine is a severe, painful headache that is often preceded or accompanied by sensory warning signs such as flashes of light, blind spots, tingling in the arms and legs, nausea, vomiting, and increased sensitivity to light and sound. The excruciating pain that migraines bring can last for hours or even days.
Migraine headaches result from a combination of blood vessel enlargement and the release of chemicals from nerve fibers that coil around these blood vessels. During the headache, an artery enlarges that is located on the outside of the skull just under the skin of the temple (temporal artery). This causes a release of chemicals that cause inflammation, pain, and further enlargement of the artery.
A migraine headache causes the sympathetic nervous system to respond with feelings of nausea, diarrhea, and vomiting. This response also delays the emptying of the stomach into the small intestine (affecting food absorption), decreases blood circulation (leading to cold hands and feet), and increases sensitivity to light and sound.
More than 28 million Americans suffer from migraine headaches, and females are much more likely to get them than males.
What causes migraines?
Some people who suffer from migraines can clearly identify triggers or factors that cause the headaches, but many cannot. Potential migraine triggers include:
• Allergies and allergic reactions
• Bright lights, loud noises, and certain odors or perfumes
• Physical or emotional stress
• Changes in sleep patterns or irregular sleep
• Smoking or exposure to smoke
• Skipping meals or fasting
• Menstrual cycle fluctuations, birth control pills, hormone fluctuations during menopause onset
• Tension headaches
• Foods containing tyramine (red wine, aged cheese, smoked fish, chicken livers, figs, and some beans), monosodium glutamate (MSG), or nitrates (like bacon, hot dogs, and salami)
• Other foods such as chocolate, nuts, peanut butter, avocado, banana, citrus, onions, dairy products, and fermented or pickled foods.
Triggers do not always cause migraines, and avoiding triggers does not always prevent migraines.
What are the symptoms of migraine?
Symptoms of migraine can occur a while before the headache, immediately before the headache, during the headache, and after the headache. Although not all migraines are the same, typical symptoms include:
• Moderate to severe pain, usually confined to one side of the head, but switching in successive migraines
• Pulsing and throbbing head pain
• Increasing pain during physical activity
• Inability to perform regular activities due to pain
• Increased sensitivity to light and sound
Many people experience migraines with auras just before or during the head pain, but most do not. Auras are perceptual disturbances such as confusing thoughts or experiences and the perception of strange lights, sparkling or flashing lights, lines in the visual field, blind spots, pins and needles in an arm or leg, or unpleasant smells.
Migraine sufferers also may have premonitions called prodrome that can occur several hours or a day or so before the headache. These premonitions may consist of feelings of elation or intense energy, cravings for sweets, thirst, drowsiness, irritability, or depression.
How is migraine diagnosed?
Physicians will look at family medical history and check the patient for the symptoms described above in order to diagnose migraine. The International Headache Society recommends the "5, 4, 3, 2, 1 criteria" to diagnose migraines without aura. This stands for:
• 5 or more attacks
• 4 hours to 3 days in duration
• At least 2 of unilateral location, pulsating quality, moderate to severe pain, aggravation by or avoidance of routine physical activity
• At least 1 additional symptom such as nausea, vomiting, sensitivity to light, sensitivity to sound.
Tests such as electroencephalography (EEG), computed tomography (CT), magnetic resonance imaging (MRI), and spinal tap may also be performed that check for:
• Bleeding within the skull
• Blood clot within the membrane that covers the brain
• Dilated blood vessel in the brain
• Too much or too little cerebrospinal fluid
• Inflammation of the membranes of the brain or spinal cord
• Nasal sinus blockage
• Postictal headache (after stroke or seizure)
How is migraine treated and prevented?
Migraine treatment (abortive therapies) and prevention (prophylactic therapies) focus on avoiding triggers, controlling symptoms, and taking medicines. Over-the-counter medications such as naproxen, ibuprofen, acetaminophen (paracetamol), and other analgesics like Excedrin (aspirin with caffeine) are often the first abortive therapies to eliminate the headache or substantially reduce pain. Anti-emetics may also be employed to control symptoms such as nausea and vomiting.
Serotonin agonists such as sumatriptan may also be prescribed for severe migraines or for migraines that are not responding to the over-the-counter medications. Similarly, some selective serotonin reuptake inhibitors (SSRIs) - antidepressants such as tricyclics - are prescribed to reduce migraine symptoms although they are not approved in all countries for this purpose.
Another class of abortive treatments are called ergots, which are usually effective if administered at the first sign of migraine. Other drugs have also been used to treat migraine such as combinations of barbituates, paracetamol or aspirin, and caffeine (Fioricet or Fiorinal) and combinations of acetaminophen, dichloralphenazone, and isometheptene (Amidrine, Duadrin, and Midrin). If vomiting makes drugs difficult to ingest, anti-emetics will be prescribed.
Migraine prevention begins with avoiding things that trigger the condition. The main goals of prophylactic therapies are to reduce the frequency, painfulness, and duration of migraine headaches and to increase the effectiveness of abortive therapies. There are several categories of preventive migraine medicine, ranging from diet changes and exercise to prescription drugs. Some of these include:
• Prescription beta blockers, anticonvulsants, and antidepressants
• Botulinum toxin A (Botox)
• Herbs and vitamins such as butterbur, cannabis, coenzyme Q10, feverfew, magnesium citrate, riboflavin, B12, melatonin
• Surgery that severs corrugator supercilii muscle and zygomaticotemporal nerve in the brain
• Spinal cord stimulator implantation
• Hyperbaric oxygen therapy
• Vision correction
• Exercise, sleep, sexual activity
• Visualization and self-hypnosis
• Chiropractic care or acupuncture
• Special diets such as gluten free
It is possible for people to get medication overuse headache (MOH), or rebound headache, when taking too many medications in an attempt to prevent migraine.