Headache

A guide to headache causes and treatments

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Migraine

Migraine is the commonest cause of disabling headaches in the general population. Epidemiological studies throughout the world, using the International Headache Society’s definition of headache, have all shown that about 18 per cent of women and six per cent of men have had at least one migraine-type headache in the previous year. Migraine occurs equally in all western countries.There is evidence from the US that fewer people of Chinese origin are affected. Migraines are actually a little commoner in young boys than in young girls, but after puberty they are two or three times more common in women than in men, depending on the time of life. Migraine becomes less frequent in older patients.

Migraine with aura
In surveys of people affected by migraine in the general population, only about 18 per cent said that their attacks were preceded by an aura, which typically lasts for 20-30 minutes before the headache. In the majority of cases there is a visual disturbance. This may consist of blurred vision, flashing lights or, occasionally, a zigzag disturbance which moves across the person’s field of vision from the centre towards the edge over the course of around half an hour. The affected person may be unable to see properly for some time while this disturbance is going on.

Tingling and numbness affecting the face, lips, tongue, cheek or fingertips are also common and may occur at the same time as the visual disturbance, or more rarely before or after it.

Weakness in one of the arms or legs is less often seen, but speech disturbances are more common. Problems with speech are limited to slurring words in most cases, but some people experience difficulty in finding their words, again usually for 20-30 minutes. As was explained earlier, these symptoms are all believed to be due to an electrical disturbance on the surface of the brain. They are not actually caused by a disturbance of blood flow in the brain, and the risk of permanent damage to the brain is very small even after repeated attacks.

Migraine without aura
The majority of people affected by migraine do not have attacks preceded by an aura. The headache is severe, usually disabling, may be throbbing and is often made worse by exercise – even walking upstairs. It is often, but by no means exclusively, on one side of the head and it is sometimes confined to either the front or the back, though it sometimes affects the whole of one half of the head (the term migraine is derived from the Latin word ‘hemicrania’, which literally means ‘half skull’). Most affected people feel nauseous and some vomit - often repeatedly throughout the attack. Diarrhoea is not uncommon and some people pass a lot of urine, often as the headache itself is subsiding.

Migraine often runs in families. Many people report that other family members, particularly the female ones, also get migraines. Recent studies have shown that migraine is two or three times more common in immediate blood relatives (parents, children, brothers and sisters) of affected people than it is in the general population. It seems likely that the combination of several different genes dictates whether or not a person will develop migraine. A great deal of research is going on at present to try to identify which genes these are, but progress is slow in a very complex condition.

How is migraine treated?
It has been recognised for many years that migraine is very disabling, even though life expectancy is not affected. Not only are some people confined to bed for days at a time, but those who do get to work are clearly rather less effective when they get there, and the overall cost to British business has been estimated to be several million pounds a year. Many drug companies are therefore attempting to develop new, more effective treatments for headache in the form of both curative and preventative drugs.

Painkillers
Most people affected by migraine will already have tried paracetamol, aspirin and perhaps anti-inflammatory drugs such as ibuprofen (Nurofen), before they seek advice from their doctor.There are a number of effective drugs which are only available on prescription, including more substantial doses of anti-inflammatory drugs called Triptans. Ergotamine, which is contained in preparations such as Cafergot or Migril, remains available but is less often prescribed. All these  treatments have their advantages and disadvantages. Aspirin, paracetamol and ibuprofen are relatively safe in the majority of people unless they take a considerable overdose. All anti-inflammatory drugs can cause indigestion and even stomach ulcers.

Codeine and related drugs will often cause constipation, and the risk of them causing a continuous headache has already been discussed. Triptans are relatively more expensive; and while they have proved highly effective in about 80 per cent of affected people, some develop short-term side effects such as tingling and aching muscles, and those who get relatively prolonged headaches often find that the pain returns after the effect of the drug has worn off. Ergotamine is particularly powerful but it is poorly absorbed by mouth and often worsens the nausea and vomiting. It is particularly likely to cause a continuous headache if taken too frequently.

Prevention
If headaches occur twice or more each month, daily drug treatment should be considered. A wide variety of different drugs have been shown to be effective in the prevention of migraine in a number of large-scale trials. In many cases their usefulness was at first discovered by chance, and no-one has yet been able to explain why most of these drugs work.

Beta blocking drugs
Beta blockers are used to treat angina and high blood pressure. They work by blocking the beta receptor for adrenaline on the heart. It has been found that some, but by no means all of these drugs are of use in treating migraine. The useful drugs include propranolol, metoprolol and atenolol.

Although these drugs slow up the heart and lower the blood pressure slightly, this levels out when all the beta receptors have been blocked. Many people affected by migraine seem to require larger doses of these drugs, but most are able to tolerate them without undue side effects. A few people find that dizziness when they stand up or coldness of the fingers and toes in cold weather limit the dose they are able to take. These drugs are effective in about two thirds of people and can be taken safely for many months or years if necessary.

Pizotifen
This is a drug which acts on receptors for the neuro-transmitter serotonin and also proves helpful in about two thirds of people. It does not affect the blood pressure but can make people feel sleepy and often increases the appetite. If you are prescribed this drug you will find that you won’t put on weight if you eat what you normally eat rather than listening to your appetite.

Methysergide (a drug that is related to ergotamine) is much older in its use and requires specialist advice. It often proves effective in people who have not been helped by other treatments. Some people benefit from anti-nflammatory painkillers taken on a regular basis, others from the anti-epilepsy drug sodium valproate (Epilim) and topiramate (Topamax), and others from antidepressants, particularly amitriptyline and dothiepin (Prothiaden).

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