Migraine
Migraine
Migraine is a neurological syndrome characterized by altered bodily perceptions, severe headaches, and nausea. Physiologically, the migraine headache is a neurological condition more common to women than to men. The word migraine was borrowed from Old French migraigne (originally as "megrim", but respelled in 1777 on a contemporary French model). The French term derived from a vulgar pronunciation of the Late Latin word hemicrania, itself based on Greek hemikrania, from Greek roots for "half" and "skull".
The typical migraine headache is unilateral and pulsating, lasting from 4 to 72 hours; symptoms include nausea, vomiting, photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound); approximately one-third of people who suffer migraine headache perceive an aura—unusual visual, olfactory, or other sensory experiences that are a sign that the migraine will soon occur.
Initial treatment is with analgesics for the headache, an antiemetic for the nausea, and the avoidance of triggering conditions. The cause of migraine headache is idiopathic; the accepted theory is a disorder of the serotonergic control system, as PET scan has demonstrated the aura coincides with diffusion of cortical depression consequent to increased blood flow (up to 300% greater than baseline).
There are migraine headache variants, some originate in the brainstem (featuring intercellular transport dysfunction of calcium and potassium ions) and some are genetically disposed. Studies of twins indicate a 60 to 65 percent genetic influence upon their propensity to develop migraine headache. Moreover, fluctuating hormone levels indicate a migraine relation: 75 percent of adult patients are women, although migraine affects approximately equal numbers of prepubescent boys and girls; propensity to migraine headache is known to disappear during pregnancy, although in some women migraines may become more frequent during pregnancy.
Signs and symptoms
The signs and symptoms of migraine vary among patients. Therefore, what a patient experiences before, during and after an attack cannot be defined exactly. The four phases of a migraine attack listed below are common but not necessarily experienced by all migraine sufferers. Additionally, the phases experienced and the symptoms experienced during them can vary from one migraine attack to another in the same migraineur:
- The prodrome, which occurs hours or days before the headache.
- The aura, which immediately precedes the headache.
- The pain phase, also known as headache phase.
- The postdrome.
Aura
For the 20–30% of individuals who suffer migraine with aura, this aura comprises focal neurological phenomena that precede or accompany the attack. They appear gradually over 5 to 20 minutes and generally last fewer than 60 minutes. The headache phase of the migraine attack usually begins within 60 minutes of the end of the aura phase, but it is sometimes delayed up to several hours, and it can be missing entirely. Symptoms of migraine aura can be visual, sensory, or motor in nature.
Visual aura is the most common of the neurological events. There is a disturbance of vision consisting usually of unformed flashes of white and/or black or rarely of multicolored lights (photopsia) or formations of dazzling zigzag lines (scintillating scotoma; often arranged like the battlements of a castle, hence the alternative terms "fortification spectra" or "teichopsia"). Some patients complain of blurred or shimmering or cloudy vision, as though they were looking through thick or smoked glass, or, in some cases, tunnel vision and hemianopsia. The somatosensory aura of migraine consists of digitolingual or cheiro-oral paresthesias, a feeling of pins-and-needles experienced in the hand and arm as well as in the nose-mouth area on the same side. Paresthesia migrate up the arm and then extend to involve the face, lips and tongue.
Other symptoms of the aura phase can include auditory or olfactory hallucinations, temporary dysphasia, vertigo, tingling or numbness of the face and extremities, and hypersensitivity to touch.
Enhancements reminiscent of a zigzag fort structure |
Negative scotoma, loss of awareness of local structures |
Positive scotoma, local perception of additional structures |
Mostly one-sided loss of perception |
Management
Conventional treatment focuses on three areas: trigger avoidance, symptomatic control, and prophylactic pharmocological drugs. Patients who experience migraines often find that the recommended migraine treatments are not 100% effective at preventing migraines, and sometimes may not be effective at all. Pharmological treatments are considered effective if they reduce the frequency or severity of migraine attacks by 50%.
Children and adolescents, are often first given drug treatment, but the value of diet modification should not be overlooked. The simple task of starting a diet journal to help modify the intake of trigger foods like hot dogs, chocolate, cheese and ice cream could help alleviate symptoms.
For patients who have been diagnosed with recurring migraines, migraine abortive medications can be used to treat the attack, and may be more effective if taken early, losing effectiveness once the attack has begun. Treating the attack at the onset can often abort it before it becomes serious, and can reduce the near-term frequency of subsequent attacks.
Paracetamol or non-steroidal anti-inflammatory drug (NSAIDs)
The first line of treatment is over-the-counter abortive medication.
- Regarding non-steroidal anti-inflammatory drugs, a randomized controlled trial found that naproxen can abort about one third of migraine attacks, which was 5% less than the benefit of sumatriptan.
- Paracetamol (known as acetaminophen in North America) benefited over half of patients with mild or moderate migraines in a randomized controlled trial.
- Simple analgesics combined with caffeine may help. During a migraine attack, emptying of the stomach is slowed, resulting in nausea and a delay in absorbing medication. Caffeine has been shown to partially reverse this effect. Excedrin is an example of an aspirin with caffeine product. Caffeine is recognized by the U.S. Food and Drug Administration as an Over The Counter Drug (OTC) treatment for migraine when compounded with aspirin and paracetamol. Even by itself, caffeine can be helpful during an attack, despite the fact that in general migraine-sufferers are advised to limit their caffeine intake.
Patients themselves often start off with paracetamol, aspirin, ibuprofen, or other simple analgesics that are useful for tension headaches. OTC drugs may provide some relief, although they are typically not effective for most sufferers.
In all, the U.S. Food and Drug Administration has approved three OTC products specifically for migraine: Excedrin Migraine, Advil Migraine, and Motrin Migraine Pain. Excedrin Migraine, as mentioned above, is a combination of aspirin, acetaminophen, and caffeine. Both Advil Migraine and Motrin Migraine Pain are straight NSAIDs, with ibuprofen as the only active ingredient.
Analgesics combined with antiemetics
Antiemetics by mouth may help relieve symtoms of nausea and help prevent vomiting, which can diminish the effectiveness of orally taken analgesia. In addition some antiemetics such as metoclopramide are prokinetics and help gastric emptying which is often impaired during episodes of migraine. In the UK there are three combination antiemetic and analgesic preparations available: MigraMax (aspirin with metoclopramide), Migraleve (paracetamol/codeine for analgesia, with buclizine as the antiemetic) and paracetamol/metoclopramide (Paramax in UK). The earlier these drugs are taken in the attack, the better their effect.
Some patients find relief from taking other sedative antihistamines which have anti-nausea properties, such as Benadryl which in the US contains diphenhydramine (but a different non-sedative product in the UK).
Serotonin agonists
Sumatriptan and related selective serotonin receptor agonists are excellent for severe migraines or those that do not respond to NSAIDs or other over-the-counter drugs. Triptans are a mid-line treatment suitable for many migraineurs with typical migraines. They may not work for atypical or unusually severe migraines, transformed migraines, or status (continuous) migraines.
Serotonin specific reuptake inhibitors (SSRIs) are not approved by the U.S. Food and Drug Administration (FDA) for treatment of migraines, but have been found to be effective by clinical consensus.
Antidepressants
Tricyclic antidepressants have been long established as highly efficacious prophylactic treatments. These drugs, however, may give rise to undesirable side effects, such as insomnia, sedation or sexual dysfunction. SSRIs antidepressants are less established than tricyclics for migraines prophylaxis. Despite the absence of FDA approval for migraine treatment, antidepressants are widely prescribed. In addition to tricyclics and SSRIs, the anti-depressant nefazodone may also be beneficial in the prophylaxis of migraines due to its antagonistic effects on the 5-HT2A and 5-HT2C receptors It has a more favorable side effect profile than amitriptyline, a tricyclic antidepressant commonly used for migraine prophylaxis. Anti-depressants offer advantages for treating migraine patients with comorbid depression.
Ergot alkaloids
Until the introduction of sumatriptan in 1991, ergot derivatives (see ergoline) were the primary oral drugs available to abort a migraine once it is established.
Ergot drugs can be used either as a preventive or abortive therapy, though their relative expense and cumulative side effects suggest reserving them as an abortive rescue medicine. However, ergotamine tartrate tablets (usually with caffeine), though highly effective, and long lasting (unlike triptans), have fallen out of favour due to the problem of ergotism. Oral ergotamine tablet absorption is reliable unless the patient is nauseated. Anti-nausea administration is available by ergotamine suppository (or Ergostat sublingual tablets made until circa 1992). Ergot drugs themselves can be so nauseating it is advisable for the sufferer to have something at hand to counteract this effect when first using this drug. Ergotamine-caffeine 1/100 mg fixed ratio tablets (like Cafergot, Ercaf, etc.) are much less expensive per headache than triptans, and are commonly available in Asia. They are difficult to obtain in the USA. Ergotamine-caffeine can't be regularly used to abort evening or night onset migraines due to debilitating caffeine interference with sleep. Pure ergotamine tartrate is highly effective for evening-night migraines, but is rarely or never available in the USA. Dihydroergotamine (DHE), which must be injected or inhaled, can be as effective as ergotamine tartrate, but is much more expensive than $2 USD Cafergot tablets.
Steroids
Based on a recent meta analysis a single dose of IV dexamethasone, when added to standard treatment, is associated with a 26% decrease in headache recurrence.
Other agents
If over-the-counter medications do not work, or if triptans are unaffordable, the next step for many doctors is to prescribe Fioricet or Fiorinal, which is a combination of butalbital (a barbiturate), paracetamol (in Fioricet) or acetylsalicylic acid (more commonly known as aspirin and present in Fiorinal), and caffeine. While the risk of addiction is low, butalbital can be habit-forming if used daily, and it can also lead to rebound headaches. Barbiturate-containing medications are not available in many European countries.
Amidrine, Duradrin, and Midrin is a combination of acetaminophen, dichloralphenazone, and isometheptene often prescribed for migraine headaches. Some studies have recently shown that these drugs may work better than sumatriptan for treating migraines.
Antiemetics may need to be given by suppository or injection where vomiting dominates the symptoms.
Recently it has been found that calcitonin gene related peptides (CGRPs) play a role in the pathogenesis of the pain associated with migraine as triptans also decrease its release and action. CGRP receptor antagonists such as olcegepant and telcagepant are being investigated both in vitro and in clinical studies for the treatment of migraine.
Preventive treatment
Preventive (also called prophylactic) treatment of migraines can be an important component of migraine management. Such treatments can take many forms, including everything from taking certain drugs or nutritional supplements, to lifestyle alterations such as increased exercise and avoidance of migraine triggers.
