Migraine

Migraine explained

Migraine is a common condition that can have a major impact on a person's life.[1]

A migraine is a severe recurring headache that may or may not be preceded by an aura - a period during which the person experiences neurological symptoms, for example, visual disturbances or sensory changes.[2]

It is thought that migraines may be triggered by excess, followed by reduced, excitation of the cells of the brain (neurons).[3] However, there appear to be changes in the vascular system as well - for example, the bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. of people who experience migraines may clot more easily than that of others.[4]

The mechanism behind the start of a migraine is not fully understood,[5] although people often find that their migraines may be triggered by certain factors. Examples include:[2]

  • A change of weather
  • Hunger
  • Stress
  • Lack of sleep
  • Alcohol
  • Foods such as chocolate, dairy products or citrus fruit.

Symptoms and signs

Up to 80 per cent of people who experience migraines find that they can anticipate when an attack will occur by recognising certain symptoms; these may be present for up to 2 days before the migraine attack itself. Such symptoms may include:[2]

  • Depression
  • Anxiety
  • Irritability
  • Difficulty concentrating.

When an aura does occur, the neurological symptoms (see below) develop over a period of 5 to 20 minutes and last for less than an hour.[6]

Most symptoms associated with an aura are visual; for example, people experiencing migraines may see shimmering 'zigzags' or irregular patterns, or they may have reduced vision in a specific area of their visual field (scotoma). Sensory auras may consist of numbness, tingling or a pins-and-needles sensation and usually affect the hand, then the face. The person's speech may also be slurred.[2,7]

According to the International Headache Society, the characteristics of a migraine headache include:[6]

  • Pain on just one side of the head
  • A pulsing quality
  • Aggravation by simple physical activity
  • Association with nausea and intolerance of light (photophobiaAn abnormal sensitivity to light.) and noise (phonophobia).

Migraine attacks usually last from 4 to 72 hours. In some cases, a migraine aura may occur without the person experiencing any headache at all.[6]

Risk factors and prevention

Boys tend to experience migraine at an earlier age than girls; however, migraines are 2 or 3 times more common in women than in men.[8] Sometimes, migraines may be linked to the use of oral contraceptives.[1]

Migraines are most common around mid-life, and may be seen more frequently in people with certain other conditions such as epilepsy.[8]

A family history of migraine increases the risk of someone experiencing the condition, which appears to have a geneticRelating to the genes, the basic units of genetic material. component.[5,9] Despite this, specific genes relating to the most common types of migraine have not yet been identified.[10]

Strategies to help prevent migraine attacks include:[11]

  • Avoiding migraine triggers
  • Adopting a healthy lifestyle (including making sure you get regular sleep and exercise, and eat regularly to avoid hunger)
  • Methods such as biofeedback (a means of monitoring physical tension and using learned techniques to control stressRelating to injury or concern.).

Tests and diagnosis

Migraines are diagnosed on the basis of symptoms, rather than routinely performing tests such as imaging of the brain.[1,12]

When someone experiences what may be a migraine, it is important to have what are known as 'secondary headaches' ruled out - that is, headaches caused by an underlying disease (such as an abnormality of the bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. vessels, also known as a vascular malformationAbnormalities in the blood vessels., or an infectionInvasion by organisms that may be harmful, for example bacteria or parasites. such as meningitis). Features that may suggest an underlying disease as a cause include:[13,14]

  • A headache that begins suddenly
  • Worsening pain levels
  • A headache that starts only when the person undergoes exercise
  • Any swelling of the optic disc (papilloedema), as seen using an ophthalmoscope, or other neurological signs
  • Fever and neck stiffness.

These features may prompt a doctor to undertake imaging of the brain,[2,13,14] which can be done with computed tomography (CTA scan that generates a series of cross-sectional X-ray images.) or magnetic resonance imagingA technique for imaging the body that uses electromagnetic waves and a strong magnetic field. (MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field.).

Choosing treatments

Because migraines differ so much from person to person, it is important that treatment is geared to the individual. [1] Different aspects include:

Treatment of an acute attack

An acuteHas a sudden onset. migraine attack may be treated using simple painkillers, specific anti-migraine medications and/or therapy to treat nausea.[1]

Painkillers used to treat acuteHas a sudden onset. migraine attacks include:[1]

  • Paracetamol
  • Aspirin
  • Non-steroidal anti-inflammatoryAny drug that suppresses inflammation drugs (NSAIDsA group of drugs that provide pain relief and reduce inflammation. )
  • Cyclooxygenase 2 inhibitors
  • Opiates.

Sometimes, simple painkillers such as NSAIDsA group of drugs that provide pain relief and reduce inflammation. cannot relieve a migraine. In these cases, migraine-specific drugs may help. These anti-migraine medications include:[1,2,15]

  • Triptans
  • Ergot alkaloids.

Triptans work in several ways, for example, by constricting the cranial bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. vessels and reducing the excitation of the nerveBundle of fibres that carries information in the form of electrical impulses. cells (neurons).[2] If one type of triptan is not effective, another may still work.[1,15]

Ergot alkaloids are not used as often as triptans because they can cause side-effects such as medication-overuse headache.[16]

Treatment for nausea can be effective in relieving migraine pain as well as easing the queasiness that might accompany a migraine attack.[16]

Prophylactic (preventive) treatment (drugs) where appropriate

If you suffer from recurrent migraines that interfere with the daily activities of life, you may consider taking preventive medication.[1,2,15] This should be started at a low dose and increased slowly, guided by how well you respond to the treatment. Sometimes, a matter of months may be needed before the benefit is seen.[2,11] Keeping a diary can make it easier to assess your response.[2]

A wide range of preventive treatments is currently in use.[15] The most effective include beta-blockersA group of drugs that block beta-receptors to slow the heart rate, or constrict the airways and arteries. , tricyclic antidepressants and anti-seizureUncontrolled electrical activity within the brain, leading to convulsions or an alteration in mental state. medications. NSAIDsA group of drugs that provide pain relief and reduce inflammation. may also help.[2,15,17]

Small studies suggest that the herb feverfew may be effective in the prevention of migraine - reducing the frequency of attacks as well as their duration[18] - although findings have been conflicting.[19]

Other measures, such as relaxation training

If you suffer from migraine, a variety of options are available that do not involve taking medication. Evidence suggests that these treatments are very effective in migraine therapy and may halve migraine symptoms compared with receiving no treatment. Examples include:[20]

  • Relaxation training
  • Biofeedback therapy
  • Stress-management training
  • Cognitive behavioural therapy (CBT).

Outlook and living with migraine

Migraine can impact on many aspects of a person's life, for example, on their social and family life, as well as affecting them in the workplace.[21,22]

Lifestyle changes can lead to less frequent, as well as shorter, attacks.[21] Prophylactic medications and additional preventive measures such as stressRelating to injury or concern.-management therapy can also minimise the overall impact of migraines.

Migraine has been found to be associated with an increased risk of ischaemic stroke Any sudden neurological problem caused by a bleed or a clot in a blood vessel. - that is, a stroke caused by a clot blocking the bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. supply to the brain.  This risk is greater among women and those who have other risk factors such as smoking and using oral contraceptives.[4]

Fortunately, many risk factors for stroke Any sudden neurological problem caused by a bleed or a clot in a blood vessel. (and for cardiovascular disease in general) can be modified, bringing any risk down to a minimum.

References: 
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  2. Evans RW. Migraine: a question and answer review. Med Clin N Am 2009; 93: 245-62.
  3. Rogawski MA. Common pathophysiologic mechanisms in migraine and epilepsy. Arch Neurol 2008; 65: 709-14.
  4. Schürks M, Rist PM, Bigal ME et al. Migraine and cardiovascular disease: systematic review and meta-analysis. BMJ 2009; 339: b3914.
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