Migraine Headaches: Causes, Symptoms and Treatment
A migraine is a specific form of recurring headache that can sometimes be very intense. A lot of people get migraine attacks, especially women. They are responsible for about one in six of all headaches and are also one of the commonest causes of children’s headaches. Migraine usually only affects one side of the head and causes constant pain with irregular throbbing or pounding, which is made worse by movement of the head or lifting heavy weights. The condition is also associated with disturbed vision, nausea and a dislike of bright light and loud noise. Migraine responds to painkillers but some patients need to take drugs to prevent regular attacks.
Individual migraine attacks can be provoked by triggers which may be hormonal (e.g., menstruation), dietary (e.g., chocolate, caffeine, alcohol, aged cheese, food additives, medications), environmental (e.g., weather and pressure changes, loud sounds, unfamiliar smells, secondhand smoke, bright lights), psychological (e.g., stress, depression), physical exertion, disturbed sleep pattern or entirely specific to each individual (e.g., a migraine attack after a flight).
In the most common form of migraine, the attacks are recurrent, on one side of the head only and throbbing. The pain is made worse by movement, noise and light. Migraine attacks typically last for several hours and can be relieved by sleep. Along with the headache, they usually involve nausea and sensitivity to bright lights and loud noise.
In addition to these symptoms, about one in ten patients get a warning that a migraine is about to start (this is known as an aura). A headache usually follows immediately after the aura though there may be a delay of up to an hour. The aura symptoms consist of visual disturbance and are not usually present during the headache phase. They include:
- Blotting out of part of vision
- Flashing lights
- Seeing jagged lines that look like battlements
- Showers or sparks in the vision
Other less common general symptoms of migraine which can occur include agitation, congestion of the nose with mucus, diarrhea, flushing, irritability and sleepiness. However, there are also some rarer types of migraine. For instance, it is possible to get recurrent auras without headaches. These other types of migraines are:
- Basilar migraine. In this type, dizziness, double vision, unsteadiness or fainting may precede the headache.
- Hemiplegic migraine. Patients with this type of migraine develop unusual symptoms as part of the aura, including weakness of a limb or one side of the body or numbness around the hand or one side of the body accompanied with difficulty speaking. This condition can run in families.
- Ophthalmoplegic migraine. It is characterized by a headache with a very droopy eyelid and an eye which does not move normally.
When it comes to the frequency of migraine attacks, it varies from a rare headache every few months to daily headaches of one or two hours duration.
The precise cause of migraine headaches remains unknown. The headaches often occur during periods of stress or after a stressful time. Some patients may find that chocolate, wine or cheese can bring on an attack. Migraines tend to be common around puberty and can occur in some women when they are pre-menstrual. Increased migraine attacks may also be caused by the use of contraceptive pills.
In general, there are a number of possible triggers for migraine attacks, including:
- Dietary factors. They include foods and drinks such as chocolate, aged cheese, nitrite-laden processed meat, food additives such as monosodium glutamate or aspartame, wine, coffee, as well as missing a meal.
- Hormonal factors. These include menstruation, ovulation, oral contraception and hormonal replacement. For more information on the link between migraine and hormonal fluctuations read this article.
- Psychological factors. Stress, post-stress (weekend or vacation), depression, anxiety and worry have all been linked to migraines.
- Physical environment. Some attacks may be also triggered by glare, flashing lights, visual stimulation, fluorescent lighting, loud sounds, odours, secondhand smoke, weather and pressure changes and high altitude.
- Disturbed sleep pattern. This can include both a lack of sleep or too much sleep.
- Medications. Nitroglycerine, contraceptives that contain estrogen, histamine, reserpine, hydralazine and ranitidine have all been shown to trigger migraine attacks in some individuals.
- Miscellaneous. These may include head trauma, physical exertion or fatigue.
- Individual factors. They are entirely specific to each individual such as getting a migraine attack after a massage or flight.
Although there are a number of well-known triggers that can cause individual migraine attacks, it is less clear what can affect the severity or the frequency of attacks.
Risk Factors for Migraines
Migraine headaches occur in about one in six people at some point in their lives. About six out of ten people who get migraine attacks have a family history of the condition. Migraines are common in women as women are three times more likely to develop them than men. Many women experience attacks shortly before or after onset of menstruation which has to do with hormonal changes. Migraines are also a particular problem around puberty.
A migraine is often a fairly severe headache and most people will want to seek medical attention the first time they get one. The diagnosis of a migraine is based upon the observation of symptoms, but there are no specific tests for it. Most people will not exactly match the “classical” symptoms of a migraine. For example, they may not have symptoms only on one side of the head or they may not experience nausea.
Nonetheless, a key feature of migraine attacks is that they are intermittent and if there are any continuous symptoms, these should be investigated with a brain scan to make sure the headache is not a result of another more serious condition. In general, the features that a doctor will look for to diagnose a migraine headache without an aura are:
- Attacks is lasting 4-72 hours
- At least two of the following features of the headache are involved:
- It is moderate to severe
- It occurs on one side of the head
- It is aggravated by movement
- The headache is accompanied by at least one of the following:
- Phonophobia (sensitivity to loud noises)
- Photophobia (sensitivity to bright lights)
Where the diagnosis is in doubt, a patient will be referred to a neurologist to rule out more serious disorders which may cause similar symptoms to migraines. The major conditions that need to be ruled out are causes of raised pressure in the brain, including:
- Brain tumours
- Hydrocephalus (an abnormal increase of cerebrospinal fluid around the brain)
- Subdural hematoma (bleeding in the brain of an older person following a bang to the head)
- Subarachnoid hemorrhage (bleeding in the space between the brain and its membrane coverings)
In addition, conditions causing elevated blood pressure in general and, therefore, also in the brain include:
- Pre-eclampsia (a condition causing raised blood pressure in pregnant women)
- Phaeochromocytoma (a rare tumour of the adrenal gland causing increased adrenaline levels, which in turn cause raised blood pressure)
However, these conditions are very rarely confused with migraines because they do not cause a recurring headache over long periods of time.
Other conditions that may cause recurrent headaches that often show symptoms similar to a migraine are:
- Tension headaches. They are the most frequent type of headaches. This is where the pain is all over the head (not just on one side as with a migraine) and is often described as feeling like a tight band or as pressure weighing down. Tension headaches do not get worse as a person walks around or goes upstairs as it usually happens with a migraine. They can recur frequently like a migraine and can occur with a migraine and are, therefore, often difficult to tell apart.
- Cluster headaches. In this condition, short regular attacks of severe one-sided stabbing pains occur, usually around the eye. On the same side as the headache, patients get a red, tearful eye with a small pupil and a drooping eyelid. Some people may also get a running nose, flushing and sweating on this side of the face.
- Cranial arteritis (inflammation of arteries in the brain).
- Head injury.
Diagnostic tests that a general practitioner and a neurologist may need to perform include blood tests, brain scans (e.g., computerized tomography scans, magnetic resonance imaging) and sometimes also a spinal tap if an infection or bleeding in the brain are suspected.
During a migraine attack, treatment is with painkillers and medications to reduce nausea. For severe attacks with aura, a doctor may prescribe medications to shorten the attack known as triptans (e.g., sumatriptan, almotriptan, eletriptan, rizatriptan, frovatriptan, naratriptan, zolmitriptan that are available under various trade names) or sometimes ergotamine and caffeine combination drugs (e.g., Cafergot). For regular migraine attacks, preventive medications such as an antidepressant amitriptyline, anti-seizure drugs (e.g., topiramate, valproate sodium), beta blockers (e.g., metoprolol tartrate, propranolol, timolol) or onabotulinumtoxinA can be used to reduce frequency.
Each of these preventative treatments works for about half the people who try it. Ideally none of these medications should be taken during pregnancy. Women should talk to their doctor well before they plan to get pregnant about necessary adjustments to their migraine treatment.
Some patients may also benefit from complementary treatments for migraines. For alternative migraine treatments read this article.
Preventing Migraine Attacks
Many patients with migraine headaches have a strong family history of the condition and studies have linked this to a particular genetic make-up. Migraine is not a preventable condition but attacks can be reduced by taking regular preventative drugs and by identifying and avoiding the triggers that bring on an attack. For information on identifying foods that can cause a migraine attack read this article.
Where to Seek Advice and Help: The Migraine Trust