Presented by: Meredith Barad, MD
Clinical Assistant Professor, Anesthesia
October 22, 2015
Migraine headaches are the most common type of headache, affecting 13 percent of all Americans. It’s the most prevalent health issue in the United States, affecting 36 million people—more cases than diabetes, cancer, and heart disease. Women are three times more likely to suffer from migraine than men, and the incidence in women seems to be associated with hormonal changes such as menstruation, pregnancy, and menopause.
More than six of 10 diagnosed patients report that their migraine episodes leave them severely impaired. While they can start in young children and teens, migraines tend to peak in during the 30s and start to diminish in the 50s, especially in women. An early age of onset is associated with poor outcome.
Almost two-thirds (63 percent) of migraineurs report experiencing migraine one to four times a month; 4 percent suffer from chronic headache of 15 days or more a month. For an official diagnosis of migraine, a person must have had at least five attacks, each lasting four to 72 hours.
“The course can vary over the lifetime,” said Meredith Barad, MD, a pain management specialist and clinical assistant professor of anesthesiology, at a presentation sponsored by the Stanford Health Library. “There’s not one pattern—it varies by individual.”
A migraine headache can cause intense unilateral throbbing or a pulsing sensation in one area of the head and is commonly accompanied by nausea, vomiting, and extreme sensitivity to light and sound. Attacks can cause debilitating pain that can last for hours or days.
There are two basic types of migraine—with and without an aura. About 15 to 30 percent of people experience a visual aura, a reversible symptom that manifests gradually about an hour before the onset of headache. Auras involve blind spots (scotomas), flashes of light, or squiggly lines, and can also include numbness, dizziness, changes in speech (aphasia), or tingling in the arms or legs (paresthesia).
A migraine is defined as a brain state of altered excitability capable of activating the trigeminovascular system in genetically susceptible individuals. The trigeminovascular system sustains the connection between blood vessels and neurons: When blood vessels dilate they activate neuropeptides that incite sensory nerve cells to fire, sending signals up the brainstem to the thalamus and cerebral cortex—the main areas of pain perception.
“We all have a ‘gate’ that is involved in how we perceive pain, but for migraineurs the gate is easier to open,” Dr. Barad said. “The volume gets turned way up, and they can’t turn it back down. They are in a vicious cycle of neuro-inflammation and neural excitation, and the process just keeps going.”
Triggers and Warning Signs
For susceptible individuals, a trigger like weather, stress, dehydration, certain foods or smells, or a change in routine or hormones can activate a cascade that alters the body’s status quo (homeostasis). Peripheral triggers include allergies, which induce mast cells to make histamine that then activate the trigeminovascular system. Triggers vary dramatically from person to person,and can include alcohol, loud sounds, skipping meals, and bright lights.
Migraines may be caused by an inherited susceptibility to stimulus in the brain, causing oversensitive sensory perceptions of pain, Dr. Barad said. About 60 percent of people whose parents have migraine will have the condition as well. Familial hemiplegic migraine (FHM) is one example in which migraineurs share the condition with family members. Researchers have identified 13 specific genes associated with FHM that include mutations in CACNA1A, ATP1A2, FHM2, genes that are involved in signaling between neurons in the brain.
Many people have warning signs that a migraine is imminent, a phase called prodrome. These predictive symptoms can arise about 24 hours in advance and include yawning, lethargy, irritability, and cravings—signs that the brain may be priming itself for a headache. There may be sensory sensitivity to sound, light, or sudden movement, neck pain, or allodynia (when normal movement feels painful). There also may be physical signs such as restlessness or itchy or drooping eyes (ptosis).
Treatment involves lifestyle modification, preventive and rescue medication, and alternative therapies. Behavioral strategies and lifestyle changes can make a tremendous difference, Dr. Barad said. Keep to a routine and stick to schedules for meals, exercise, and sleep. The idea is to optimize patterns to reduce stress and control triggers. She also recommends sticking to a low dose of caffeine, avoiding key food triggers like sulfites (found in red wine and dried fruit), nitrates (found in cured and processed meats), and MSG.
Although there’s no cure, medications can help reduce the frequency and severity of migraines. Preventive medications are used to reduce the frequency, severity, and length of migraines and are taken regularly, often on a daily basis. Patients are first prescribed the lowest dose to allow the body to adjust slowly, since many of these medications have side effects like weight gain, fatigue, and sleep disruption. It takes about six weeks before there is a therapeutic effect, so patients need to be conscientious about going back to their doctor for re-evaluation and follow-up care.
The most effective (Level A) medications include topiramate (an anticonvulsant drug), valproic acid (an anticonvulsant), and beta blockers (which modulate neural pathways). Level B options include selective serotonin re-uptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and tricyclic antidepressant (TCA). Some herbal remedies also appear to have a preventive effect on migraines; these include extract of feverfew, butterbur, and riboflavin.
Acute medication, or “rescue” drugs are used to alleviate the pain of a migraine and work if taken within the first 90 minutes of onset. Triptans has been shown to reduce pain within two hours for most people and appear to alleviate other migraine symptoms, such as nausea and sensitivity to light, noise, and motion. Other treatments include ergot, which is effective but nauseating for most people; dopamine antagonists. NSAIDs (aspirin and ibuprofen) should be used sparingly as a rescue drug, not as a preventive measure, Dr. Barad said.
Multiple studies have shown the benefit of alternative therapies such as biofeedback, acupuncture, and meditation. At migraine onset, Dr. Barad suggests sleep or rest in a dark room. “Sensory deprivation helps to put the ‘gate’ back in place,” she said.
Studies have shown great response using botox for people with chronic headache—15 or more headache days per month—who are not responsive to more than three other treatments. After botox was injected in 31 sites on the head, 40 to 60 percent of the PREEMPT study participants experienced less frequent headaches.
Dihydroergotamine, or DHE, appears to work on intense headaches within 48 hours. A greater occipital nerve block, used in conjunction with medication, cuts off pain messages from a major nerve at each side of the head to help break the cycle of perceived pain. A sphenopalatine ganglion block uses a similar approach to diminish pain messages from the sinuses.
Dr. Barad also described a new approach using a CGRP modulator, which takes a genetic approach to treat migraine by dampening the neuropeptides that excite neuronal activity—a key source of migraine pain. Three monoclonal antibodies are administered monthly as maintenance, and early results have been very promising, she said.
About the Speaker
Meredith Barad, MD, is a clinical assistant professor of anesthesiology and or neurology specializing in pain management and headache disorders. She received her MD from Stanford, where she completed a residency and did her fellowship in pain management. She is Board Certified in pain medicine and neurology from the American Board of Psychiatry and Neurology.
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