Thursday, June 17, 2010

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.[1][2] 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".[3]
The typical migraine headache is unilateral (affecting one half of the head) and pulsating, lasting from 4 to 72 hours;[2] symptoms include nausea, vomiting, photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound).[4][5][6] 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.[7]
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 unknown; the most common theory is a disorder of the serotonergic control system.
There are migraine headache variants, some originate in the brainstem (featuring intercellular transport dysfunction of calcium and potassium ions) and some are genetically disposed.[8] Studies of twins indicate a 60 to 65 percent genetic influence upon their propensity to develop migraine headache.[9][10] 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.

Management
Conventional treatment focuses on three areas: trigger avoidance, symptomatic control, and prophylactic pharmacological 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. Pharmacological treatments are considered effective if they reduce the frequency or severity of migraine attacks by 50%.[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.[31]
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.[citation needed]
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.[51]
• Paracetamol (known as acetaminophen in North America) benefited over half of patients with mild or moderate migraines in a randomized controlled trial.[52]
• Simple analgesics combined with caffeine may help.[53] 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.[54] Even by itself, caffeine can be helpful during an attack,[55][56] despite the fact that in general migraine-sufferers are advised to limit their caffeine intake.[56]
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.[57]
Analgesics combined with antiemetics
Antiemetics by mouth may help relieve symptoms 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).[58] 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
Main article: triptans
Sumatriptan and related selective serotonin receptor agonists are excellent for severe migraines or those that do not respond to NSAIDs[51] or other over-the-counter drugs.[52] 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.
Selective serotonin 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.[50]
Antidepressants
Tricyclic antidepressants have been long established as highly efficacious prophylactic treatments.[50] 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.[50] 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[59] and 5-HT2C receptors[60][61] 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.[50]
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 and Romania (Cofedol). 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.[62]
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.[63]
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.[64]
[edit] Status migrainosus
Status migrainosus is characterized by migraine lasting more than 72 hours, with not more than four hours of relief during that period. It is generally understood that status migrainosus has been refractory to usual outpatient management upon presentation.
Treatment of status migrainosus consists of managing comorbidities (i. e. correcting fluid and electrolyte abnormalities resulting from anorexia and nausea/vomiting often accompanying status migr.), and usually administering parenteral medication to "break" (abort) the headache.
Although the literature is full of many case reports concerning treatment of status migrainosus, first line therapy consists of intravenous fluids, metoclopramide, and triptans or DHE.[65]
[edit] Herbal treatment
The herbal supplement feverfew (more commonly used for migraine prevention, see below) is marketed by the GelStat Corporation as an OTC migraine abortive, administered sublingually (under the tongue) in a mixture with ginger.[66] An open-label study (funded by GelStat) found some tentative evidence of the treatment's effectiveness,[67] but no scientifically sound study has been done. Cannabis, in addition to prevention, is also known to relieve pain during the onset of a migraine.

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