Migraine can be defined as an episodic headache, lasting from 4 to 72 hours, associated with nausea and vomiting. Some attacks of migraine are preceded by an aura (classical migraine), typically of visual symptoms. There is complete freedom from symptoms between attacks. Daily headaches are not migraine.

The name migraine is derived from the word hemicrania meaning a one-sided headache, although the headache can be generalized. But migraine is more than just a head-ache and the headache is not necessarily the major symptom. Most people feel sick and are often unable to continue their normal daily activities.

Some have to lie still in a quiet, darkened room until the attack is over. Many cannot bear even the thought of food but others find eating takes the edge off the nausea.

Migraine has been likened to a power cut as the whole body seems to shut down until the attack is over. Lethargy is a common symptom and every task seems to take twice as long – if it is possible to tackle it at all. The stomach stops functioning normally, making it harder for medication to be absorbed into the bloodstream, especially if treatment is delayed. Sometimes an attack ends with vomiting but in most cases the headache improves after a good sleep or gradually fades away.

An attack of migraine can be very frightening. Those experiencing the visual disturbances of the aura are often scared of perman-ently losing their vision. Strokes and brain tumours are also common fears. Fortunately, such sinister causes are rare and other symptoms may be apparent before headaches. Although the symptoms of migraine can be disturbing, they are not life threatening and the body returns to normal between attacks.

SYMPTOMS OF MIGRAINE
Headache Visual disturbances Feeling sick Vomiting Aversion to light Aversion to food Lethargy

Duration of attacks

The headache of a migraine usually eases within 24 hours of starting but can last anything from part of a day to three days. Often it takes another day or so to get back to normal as symptoms of tiredness and feeling washed out remain even after the headache has gone. A few feel extra well after an attack – possibly due to relief that the attack is over.

Children often have short and sharp attacks lasting only a few hours. With increasing age the attacks typically last longer but are less severe, and the aura may become more frequent.

Between attacks sufferers feel their usual selves – forgetting how bad they felt until the next attack.

Frequency of attacks

The frequency of migraine varies considerably both between indivi-duals and in the same person. The attacks may come once or twice a month during a bad patch but a few unlucky people might have a spell of attacks occurring once or twice a week. This could be followed by a gap of several months or even years without an attack, for no apparent reason. In general, attacks become less frequent after the age of 55 although this is not always the case.

How common is migraine?

At a conservative estimate, migraine affects at least five million people in the UK, i.e. about 10 per cent of the population. It is difficult to give a precise figure because some people may only have three or four attacks in a lifetime and not recognize them as migraines. Most population studies to date are based on the results of questionnaires. These can give misleading figures as it is very difficult to diagnose migraine correctly by questionnaire.

Although migraine affects at least 10 per cent of the population, it is difficult to assess how common the condition is and how many new cases there are, partly because so few people with migraine visit the doctor.

Many sufferers have seen close relatives struggle through attacks and are under the false impression that little can be done to help them. Others feel they are wasting the doctor’s time because between attacks they are healthy.

Another problem is that a uni-versally accepted definition of migraine was only introduced in 1988. Previous studies undertaken before this date used inconsistent criteria, therefore making it impos-sible to compare results.

However, several studies have been undertaken using the new definition and the results from different countries are similar.

In Denmark, 1,000 men and women aged between 25 and 64 were interviewed about their general health and headaches. The researchers found that eight per cent of men and 25 per cent of women questioned had had an attack of migraine at some time in their lives.

A survey in America set out to analyse the results of a question-naire sent to 15,000 households. Replies were received from 63 per cent of people aged between 12 and 80. From this group, six per cent of men and 18 per cent of women reported having one or more migraine headaches each year.

Who gets migraine?

Sex

Migraine affects more women than men – the ratio is three to one. Hormonal changes in women are the obvious reason for this difference between the sexes and accounts for the fact that, until puberty, migraine is equally prevalent in boys and girls.

Age

At least 90 per cent of the popul-ation with migraine have their first attack before the age of 40. For most people the migraine starts during their teens or early twenties, although it has been diagnosed in young children and even babies. It is rare for migraine to start in people over the age of 50.

Even though migraine starts in the young, it may not become a problem until later life. Studies show that women are most likely to have problems with migraine when they reach middle age. In men the pattern is fairly consistent throughout their lives.

Migraine usually improves in later life for both sexes, although a few continue to have attacks.

Intelligence

For many years it was thought that migraine sufferers were more intelligent than non-sufferers. This myth was dispelled when it was found that people who have had more years of education are more likely to seek treatment from a doctor. In fact migraine affects people from all walks of life regardless of race, intelligence or social class.

Trigger factors

Although doctors do not know why people get migraine, it is known that certain factors are involved in triggering an attack. Most people have read or been told that they should avoid cheese, chocolate and red wine if they have migraine.

Unfortunately, for most people simply avoiding certain foods is insufficient to prevent the attacks. This is because trigger factors build up over a period of time and act in combination to cross the threshold of an attack. This explains why missing a meal or having a glass of wine does not always trigger an attack.

If you drink a glass of wine when other triggers are present, such as after an exhausting and stressful day at work or around the time of your period, an attack may result.

Triggers may change over the years even though the attacks themselves are the same. Stress, late nights etc. may have been the most important triggers when you were younger but in later years neck and back problems may play a greater role.

Specific foods

Twenty per cent of sufferers link certain foods to their migraine. The most common foods are chocolate, cheese and citrus fruits, commonly referred to as the three Cs. Alcohol, particularly red wine, is also a recognized trigger.

There is clear evidence that certain foods can provoke migraine in a few susceptible individuals. There is no scientific evidence that migraine has an allergic basis and food intolerance is a more accepted term.

Allergy tests are of little value in testing for intolerance to implicated foods as the tests are not sensitive or specific enough.

Whatever the mechanism, many people strictly avoid suspect foods without first discovering whether or not they contribute to their own headache. Anyone who thinks that a certain food is precipitating attacks should eliminate that food from their diet for two months, keeping a diary to see if there is any change in their attacks. If the frequency of attacks is unchanged, the food can be reinstated and another suspected food eliminated for a further two months. However, the only certain way of identifying food triggers is to avoid all suspected foods by following a strict elimination diet. This should only be done under the supervision of a doctor or dietician because of the risk of malnutrition.

Most people find that they can control their migraines by identifying other triggers, making only minimal changes to their diet.

Lack of food

Missing meals, snack lunches or eating sugary snacks instead of a proper meal can all lead to an attack. Breakfast is a particularly important meal. Some migraine sufferers have controlled their attacks by eating small nutritious snacks at frequent intervals.

Changes in sleeping pattern

Sleepless nights, overwork and too many late nights can result in becoming over-tired and triggering a migraine. Conversely, sleeping in, even for just half-an-hour longer than usual or lying in bed dozing, starts up a headache in many people. Unfortunately, this is often at a weekend when they want to relax.

Hormonal changes in women

Many women relate their attacks to the menstrual cycle and may have had their first migraine around the time of their first period. Taking the oral contraceptive pill can aggravate migraine, although a few women do notice an improvement.

It is wise to stop the Pill if attacks become more frequent or more severe. It should not be taken by women who have attacks of classical migraine and should be discontinued by those whose attacks convert from common to classical.

Pregnancy usually leads to an improvement in migraine after the first trimester but attacks return after the baby is born.

The menopause is the most difficult time for women with migraine but little is known about the effects of hormone replacement therapy on migraine in women. The link between headaches and hormones is covered.

Head and neck pain

Muscle tension affecting the neck and shoulder muscles is a common problem, particularly if you sit hunched over a desk or VDU all day or do a lot of driving. Local pain in the head and neck can cause headaches as well as triggering migraine.

As your body ages the bones undergo arthritic changes which sometimes aggravate migraine because this puts the muscles that support the bones under more stress.

In a few cases, migraine can be aggravated by specific dental problems such as problems with wisdom teeth, bite and jaw joint. It is worthwhile checking with your dentist, especially if you grind your teeth at night or have problems with your jaw locking when you open your mouth wide.

Exercise

Hard physical exercise, especially if you are unfit, can be a trigger. Regular exercise, without overdo-ing it, can help prevent migraine attacks. It can help breathing and strengthen muscles.

Exercise also stimulates the body to release its own natural pain killers and promotes a general sense of well-being.

Travel

Be careful on long journeys, especially if they involve a change in meal and sleep patterns. Allow enough time so that you are not rushed, and take something to eat in case meals are delayed.

Stress

Anxiety and emotion do play an important part in migraine but other triggers such as missing meals or not sleeping properly often go hand in hand with stress. Some people have more attacks when under stress; others cope with stress but have attacks when they eventually have a chance to relax. Even pleasant things can be stressful, for example, promotion at work or a heavy, but interesting, assignment. Stress in one guise or another is unavoidable but it is important to recognize that these stresses exist and find ways of dealing with at least some of them.

Other causes

Bright lights, loud noise, strong smells, changes in the weather, smoky environments and hot stuffy rooms (such as the cinema) can all trigger attacks in susceptible people. Why do some people get migraine and not others? Pain is usually nature’s way of telling you that something is wrong and helps to prevent further injury to the body, so an attack of migraine may have a protective role against a build up of triggers. It is generally thought that migraine can run in families, typically from mother to daughter. Although it is true to say that migraine sufferers usually have a family history of migraine, no specific gene has been identified.

Migraine is such a common condition that there is a high likelihood of there being at least one other member of the family with migraine without it being an inherited condition but researchers continue to look for a genetic link. It is possible that everyone has the potential to experience migraine but that the threshold for an attack is higher in some people than in others.

These people would need a greater number of triggers present at any one time to precipitate an attack than those people with a lower threshold.

KEY POINTS

• Migraine is an episodic headache, lasting four to 72 hours, associated with nausea and vomiting.
  
• The frequency of attacks varies between individuals and in the same person.
  
• Migraine affects women more than men and rarely starts after the age of 50.
  
• Changes in blood flow to the brain are thought to underlie migraine attacks but trigger factors are also involved.