The word derives from HEMICRANIA, the ancient Greek for half a skull, and is a common condition characterised by recurring intense headaches, generally on one side of the head and usually accompanied by visual or gastrointestinal disturbances, or both. Attacks may last minutes to days, with total freedom between episodes.
Attacks may be provoked by a wide variety of causes including: anxiety, emotion, depression, shock, and excitement; physical and mental fatigue; prolonged focusing on computer, television or cinema screens; noise, especially loud and high-pitched sounds; certain foods – such as chocolate, cheese, citrus fruits, pastry; alcohol; prolonged lack of food; irregular meals; menstruation and the pre-menstrual period. However, often the trigger remains unidentified. Anything that can provoke a headache in the ordinary individual can probably precipitate an attack in a migrainous subject.
The precise cause is not known, but the generally accepted view is that in susceptible individuals, one or other of these causes produces spasm or constriction of the blood vessels of the brain. This in turn is followed by dilatation of these blood vessels which also become more permeable and allow fluid to pass into the surrounding tissues. This combination of dilatation and outpouring of fluid is held to be responsible for the headache.
Two types of migraine have been recognised: classical and common. The former is relatively rare and the headache is preceded by a slowly extending area of blindness in one or both eyes, usually accompanied by intermittent ‘lights’. The phenomenon lasts for up to 30 minutes and is followed by a severe, often unilateral (one-sided) headache with nausea, sometimes vomiting and sensitivity to light. Occasionally, transient neurological symptoms such as weakness in a limb may accompany the attack. The common variety has similar but less severe symptoms. It consists of an intense headache, usually situated over one or other eye. The headache is usually preceded by a feeling of sickness and disturbance of sight. In 15–20 per cent of cases this disturbance of sight takes the form of bright lights: the so-called AURA of migraine.
consists, in the first place, of trying to avoid any precipitating factor. Patients must find out which drug, or drugs, give them most relief and must always carry these with them; it is a not uncommon experience to be aware of an attack coming on and to find that there is a critical quarter of an hour or so during which treatment is effective. If not taken within this period, they may be ineffective and the unfortunate sufferer finds him or herself prostrate with headache and vomiting. In addition, sufferers should lie down; at this stage a few hours’ rest may prevent the development of a full attack.
When an attack is fully developed, rest in bed in a quiet, darkened room is likely to help; any loud noise or bright light intensifies the headache or sickness. The less food that is taken during an attack the better, provided that the individual drinks as much fluid as he or she wants. Group therapy, in which groups of around ten migrainous subjects learn how to relax, is often of help in more severe cases, whilst in others the injection of a local anaesthetic into tender spots in the scalp reduces the number of attacks. Drug treatment can be effective and those afflicted by migraine may find a particular drug or combination of drugs more suitable than others. ANALGESICS such as PARACETAMOL, aspirin and CODEINE phosphate sometimes help. A combination of buclizine hydrochloride and analgesics, taken when the visual aura occurs, may prevent or diminish the severity of an attack in some people. A previously commonly used remedy for the condition is ergotamine titrate, which causes dilated blood vessels to contract, but this must only be taken under medical supervision. In many cases METOCLOPRAMIDE (an antiemetic), followed ten minutes later by either aspirin or paracetamol, can be effective if taken early in an attack. In milder attacks, aspirin, with or without codeine and paracetamol, may be of value. SUMATRIPTAN (5-hydroxytryptamine [5HT1] AGONIST – also known as a SEROTONIN agonist) is of value for acute attacks. It is used orally or by subcutaneous injection, but should not be used for patients with ischaemic heart disease. Naratriptan is another 5HT1 agonist that is an effective treatment for acute attacks; others are almotriptan, rizariptan and zolmitriptan. Some patients find BETA-ADRENOCEPTOR-BLOCKING DRUGS (BETA BLOCKERS) such as propranolol a valuable prophylactic. A few patients with migraine may develop it in association with a congenital heart derangement called patent foramen ovale (PFO), treatment of which may help their symptoms.