What is a migraine headache?
A migraine headache is a form of vascular headache. Migraine headache is caused by vasodilatation (enlargement of blood vessels) that causes the release of chemicals from nerve fibers that coil around the large arteries of the brain. Enlargement of these blood vessels stretches the nerves that coil around them and causes the nerves to release chemicals. The chemicals cause inflammation, pain, and further enlargement of the artery. The increasing enlargement of the arteries magnifies the pain.
Migraine attacks commonly activate the sympathetic nervous system in the body. The sympathetic nervous system is often thought of as the part of the nervous system that controls primitive responses to stress and pain, the so-called "fight or flight" response, and this activation causes many of the symptoms associated with migraine attacks; for example, the increased sympathetic nervous activity in the intestine causes nausea, vomiting, and diarrhea.
Sympathetic activity also delays emptying of the stomach into the small intestine and thereby prevents oral medications from entering the intestine and being absorbed.
The impaired absorption of oral medications is a common reason for the ineffectiveness of medications taken to treat migraine headaches.
The increased sympathetic activity also decreases the circulation of blood, and this leads to pallor of the skin as well as cold hands and feet.
The increased sympathetic activity also contributes to the sensitivity to light and sound sensitivity as well as blurred vision.
Migraine afflicts 28 million Americans, with females suffering more frequently (17%) than males (6%). Missed work and lost productivity from migraine create a significant public burden. Nevertheless, migraine still remains largely underdiagnosed and undertreated. Less than half of individuals with migraine are diagnosed by their doctors.
What are the symptoms of migraine headaches?
Migraine is a chronic condition with recurrent attacks. Most (but not all) migraine attacks are associated with headaches.
Migraine headaches usually are described as an intense, throbbing or pounding pain that involves one temple. (Sometimes the pain is located in the forehead, around the eye, or at the back of the head).
The pain usually is unilateral (on one side of the head), although about a third of the time the pain is bilateral (on both sides of the head).
The unilateral headaches typically change sides from one attack to the next. (In fact, unilateral headaches that always occur on the same side should alert the doctor to consider a secondary headache, for example, one caused by a brain tumor).
A migraine headache usually is aggravated by daily activities such as walking upstairs.
Nausea, vomiting, diarrhea, facial pallor, cold hands, cold feet, and sensitivity to light and sound commonly accompany migraine headaches. As a result of this sensitivity to light and sound, migraine sufferers usually prefer to lie in a quiet, dark room during an attack. A typical attack lasts between 4 and 72 hours.
An estimated 40%-60% of migraine attacks are preceded by premonitory (warning) symptoms lasting hours to days. The symptoms may include:
1;-sleepiness,
2;-irritability,
3;-fatigue,
4;-depression or euphoria,
5;-yawning, and
6;-cravings for sweet or salty foods.
Patients and their family members usually know that when they observe these warning symptoms that a migraine attack is beginning.
Migraine aura
An estimated 20% of migraine headaches are associated with an aura. Usually, the aura precedes the headache, although occasionally it may occur simultaneously with the headache. The most common auras are:
flashing, brightly colored lights in a zigzag pattern (referred to as fortification spectra), usually starting in the middle of the visual field and progressing outward; and
a hole (scotoma) in the visual field, also known as a blind spot.
Some elderly migraine sufferers may experience only the visual aura without the headache. A less common aura consists of pins-and-needles sensations in the hand and the arm on one side of the body or pins-and-needles sensations around the mouth and the nose on the same side. Other auras include auditory (hearing) hallucinations and abnormal tastes and smells.
For approximately 24 hours after a migraine attack, the migraine sufferer may feel drained of energy and may experience a low-grade headache along with sensitivity to light and sound. Unfortunately, some sufferers may have recurrences of the headache during this period.
How is a migraine headache diagnosed?
Migraine headaches are usually diagnosed when the symptoms described previously are present. Migraine generally begins in childhood to early adulthood. While migraines can first occur in an individual beyond the age of fifty, advancing age makes other types of headaches more likely. A family history usually is present, suggesting a genetic predisposition in migraine sufferers. The examination of individuals with migraine attacks usually is normal.
Patients with the first headache ever, worst headache ever, a significant change in the characteristics of headache or an association of the headache with nervous system symptoms, like visual or hearing or sensory loss, may require additional tests to exclude diseases other than migraine. The tests may include blood testing, brain scanning (either CT or MRI), and a spinal tap.
What is the treatment for moderate to severe migraine headaches?
Migraine-specific abortive medications usually are necessary for moderate to severe migraine headaches. The abortive medications for moderate or severe migraine headaches are different than OTC analgesics. Instead of relieving pain, they abort headaches by counteracting the cause of the headache, dilation of the temporal arteries. In fact, they cause narrowing of the arteries. Examples of migraine-specific abortive medications are the triptans and ergot preparations.
Triptans
The triptans attach to serotonin receptors on the blood vessels and nerves that surround them, constrict the blood vessels, and reduce the inflammation. This stops the headache. The triptan with the longest history of use is sumatriptan (Imitrex). Sumatriptan is available in the US as an injection, oral tablet, and nasal inhaler. Zolmitriptan (Zomig) and rizatriptan (Maxalt) are newer triptans that are available as oral tablets and as tablets that melt in the mouth. Naratriptan (Amerge), almotriptan (Axert) and frovatriptan (Frovalan) are available only as oral tablets.
Traditionally, triptans were prescribed for moderate or severe migraines after OTC analgesics and other simple measures failed. Newer studies suggest that triptans can be used as the first treatment for patients with migraines that are causing disability. (Significant disability is defined as more than 10 days of at least 50% disability during a three-month period.). Triptans should be used early after the migraine begins, before the onset of pain or when the pain is mild. Using a triptan early in an attack increases its effectiveness, reduces side effects, and decreases the chance of recurrence of another headache during the following 24 hours. Used early, triptans can be expected to abort more than 80% of migraine headaches within two hours.
The U.S. Food and Drug Administration (FDA) has issued a warning about taking triptans together with medications of the SSRI (selective serotonin reuptake inhibitor) or SNRI (selective serotonin/norepinephrine reuptake inhibitor) classes. Taking these medicines together can cause a serious condition called serotonin syndrome.
Side effects of triptans
The most common side effects of triptans are facial flushing, tingling of the skin, and a sense of tightness around the chest and throat. Other less common side effects include drowsiness, fatigue, and dizziness. These side effects are short-lived and are not considered serious.
The most serious side effects of triptans are heart attacks and strokes. Triptans are effective in migraine headaches because they narrow arteries in the head; however, they also can narrow arteries in the heart. In individuals without existing carotid or coronary artery disease, the narrowing caused by triptans usually does not cause problems. However, persons whose carotid and coronary arteries are narrowed by atherosclerosis or who suffer from intermittent spasm of the coronary arteries (a condition called Prinzmetal's or variant angina), the narrowing caused by triptans can further reduce the flow of blood through the arteries and have been reported to cause heart attacks and strokes. Therefore, triptans should not be used by those who have had heart attacks and strokes, or those who have symptoms of atherosclerosis such as angina, transient ischemic attack (TIAs), and intermittent claudication.
Healthy adults may have atherosclerosis and narrowing of the coronary arteries that are "silent", that is, without past strokes, transient ischemic attacks, heart attacks, or angina. Therefore, before prescribing a triptan, a doctor should evaluate patients for possible atherosclerosis if they have one or more risk factors for developing atherosclerosis. These risk factors include cigarette smoking, diabetes mellitus, high blood pressure, high levels of LDL ("bad") cholesterol in the blood, obesity, male and over 40 years of age, female and postmenopausal, or a family member(s) who has had heart attacks at an early age. Some patients who are at risk should receive their first dose of a triptan in the doctor's office while being monitored with an electrocardiogram (EKG).
Triptans can interact with other drugs. For example, there have been rare reports of triptans causing a "serotonin syndrome" when given together with a selective serotonin reuptake inhibitor. Selective serotonin reuptake inhibitors (SSRIs) are a class of medications widely used to treat depression. The symptoms of serotonin syndrome include confusion, fever, tremor, high blood pressure, diarrhea, and sweating. Certain triptans such as sumatriptan, zolmitriptan, and rizatriptan can interact with monoamine oxidase inhibitors. Propranolol (Inderal) can raise rizatriptan blood levels. Cimetidine (Tagamet) can increase zolmitriptan blood levels.
Triptans should not be used in pregnant women and are not generally used in young children.
Ergots
Ergots, like triptans, are medications that abort migraine headaches. These may be combined with caffeine and/or other pain relief medications in combination products. Examples of ergots include ergotamine preparations (Ergomar, Wigraine, and Cafergot) and dihydroergotamine preparations (Migranal, DHE-45). Ergots, like triptans, cause constriction of blood vessels, but ergots tend to cause more constriction of vessels in the heart and other parts of the body than the triptans, and their effects on the heart are more prolonged than those of the triptans. Therefore, they are not as safe as the triptans. The ergots also are more prone to cause nausea and vomiting than the triptans. The ergots can cause prolonged contraction of the uterus and miscarriages in pregnant women.
Midrin
Midrin is used to abort migraine and tension headaches. It is a combination of isometheptene (a blood vessel constrictor), acetaminophen (a pain reliever), and dichloralphenazone (a mild sedative). It is most effective if used early during a headache; however, because of its potent blood vessel constricting effect, it should not be used in persons with high blood pressure, kidney disease, glaucoma, atherosclerosis, liver disease, or taking monoamine oxidase inhibitors.
What other medications are used for treating migraine headaches?
Narcotics and butalbital-containing medications sometimes are used to treat migraine headaches; however, these medications are potentially addicting and are not used as initial treatment. They are sometimes used for individuals whose headaches fail to respond to OTC medications but who are not candidates for triptans either due to pregnancy or the risk of heart attack and stroke.
In migraine sufferers with severe nausea, a combination of a triptan and an antinausea medication, for example, prochlorperazine (Compazine) or metoclopramide (Reglan) may be used. When nausea is severe enough that oral medications are impractical, intravenous medications such as DHE-45 (dihydroergotamine), prochlorperazine (Compazine), and valproate (Depacon) are useful.
