What is a migraine?
Migraine is a disorder marked by severe headaches that occurs in attacks. It tends to be recurrent and variable in their duration, intensity and frequency of occurrence. Usually a migraine is more one-sided pain of the head although both side may be affected. The condition is often confused with other types of headaches. Typically migraines are chronic and the severity tends to hamper the sufferer’s quality of life.
What are the symptoms of migraines?
Migraines can be broadly classified into two types – migraine without aura or migraine with aura.
Migraine without aura
This is also known as common migraine or hemicrania simplex. It is marked by one-sided (unilateral) headaches which are pulsating in nature. The pain tends to last between 4 to 72 hours and is moderate to severe in intensity. Typically there are other symptoms associated with the pain, such as light and noise sensitivity and at times vomiting.
The attacks are aggravated by routine physical activities. It is the most common and debilitating form of migraines. The mechanism which accounts for these attacks is poorly understood. Changes in blood composition and platelet function either by external or internal influences may play a roles as a trigger.
This type of migraine can occur in some females just before menstruation (premenstrual).
Migraine with aura
It is known as a classical migraine. This type of migrain occurs in association with neurological symptoms (aura) related to localized areas of the brain and brainstem. The aura typically precedes the onset of the pain. Therefore patients are aware that the attack will commence shortly.
Visual disturbances usually affecting one vertical side of the field of vision, one-sided weakness of the body, or unusual sensations on one side of the body or difficulty forming words are some of the symptoms that are present during the aura. Most people experience visual symptoms as part of the aura.
Symptoms of nausea, headache and/or photophobia usually follow the aura. The headache usually lasts for for anywhere from a few hours to up to 72 hours. In some instances there is no headache after the aura. In rare instances, the aura could be prolonged and last up to one week thereby mimicking a stroke.
This is not a type of migraine but is worth mentioning separately. Migraines lasting for more than 72 hours (status migrainosus) or neurological symptoms lasting for more than 7 days (migrainous infarction) are among the complicated versions of migraines.
What causes migraines?
Environmental factors and hereditary factors appear to be the most likely reasons for migraines. Migraines are believed to be due to :
- Increased blood flow due to a abnormal channels between arteries and veins.
- Abnormalities in brain hormones like serotonin which causes platelets to aggregate.
- Various metabolic defects affecting the blood flow to the brain.
Despite these mechanisms, it does not explain migraines in every instance. Furthermore the cause for these abnormalities cannot always be identified or explained. There is the belief that some migraine cases may be associated with psychiatric factors.
What is the treatment for migraines?
Careful history and the patient’s own experience may serve as a guide to avoid triggers such as certain foods or stress.
- Treatment of associated hypertension or premenstrual stress or even use of psychotropic drugs may be necessary.
- Anti-serotonin drugs such as methysergide and cyproheptadine can be used.
- Drugs maintaining cranial arteries in the state of vasoconstriction or at least preventing excessive dilation are used. Ergotamine tartrate tends to constrict dilated vessels and dilate constricted vessels.
- Due to gastric atony associated with migraine, oral drugs are given along with drugs like metoclopramide.
- Clonidine is used prophylactically and drugs such as amitriptyline and propanolol that alter the effect of serotonin can also be used in prophylaxis.
- Acute pain has to be sometimes relieved by strong analgesics like pethidine or pentazocine.
- When the attack is infrequent, less than two a month there is no need for daily medication. Simple analgesics or NSAIDs are used especially when ergotamine cannot be tolerated or is ineffective.