Migraine is a common type of headache, which is often accompanied by symptoms such as nausea, vomiting, or sensitivity to light. Many people feel a throbbing pain at the front or on one side of the head. Its attacks can cause significant pain, which can be severe and last for hours to days.
There are several types of migraine, including:
1. Migraine with Aura:
Some people who get migraines have warning symptoms, called an aura before the actual headache begins. Warning signs may include visual problems (such as flashing lights) and stiffness in the neck, shoulders, or limbs.
2. Migraine without Aura:
Its attacks start without any advance warning and symptoms fall in this category.
3. Migraine without Headache:
Also known as silent migraine. In this type, a person feels warning symptoms (an aura) or other migraine symptoms, such as nausea, and sensitivity to bright light are experienced, but no headache is experienced.
Prevalence of Migraine
- According to the 2011 National Health Interview Survey, 16.6 percent of adults in the US, aged 18 years or above reported having migraine or other severe headaches.
- Recently, the American Migraine Prevalence and Prevention (AMPP) study reported an overall migraine prevalence of 11.7 percent.
- Another recent study estimated the prevalence of headaches occurring on more than 15 days per month (chronic daily headaches) in Southeast Asia to be 1.7 percent.
- A recent Swiss study reported a prevalence of 7 percent for migraine (both with and without aura), and 31.5 percent for migraine and tension-type headaches (felt as pressure on both sides of the head).
Pathophysiology
The exact cause of migraine is unknown, but it is thought to occur due to changes in the brain as well as due to some genetic causes. For many years scientists have believed that expansion (dilation) and constriction (narrowing) of blood vessels on the brain’s surface is the underlying cause of migraine headaches. However, it is now understood that migraine is caused by abnormalities in certain areas of the brain.
A “pain generator” situated in the brain sends signals to the meningeal blood vessels (located in the brain) and causes them to dilate. The dilation of blood vessels activates trigeminal sensory nerves (responsible for sensation in the face).
This is followed by a release of chemical substances such as prostaglandins, serotonin, and other inflammatory substances, which cause pain. Serotonin is responsible for controlling emotions such as attention, sleep, and pain. Therefore, changes in serotonin levels following a migraine attack increase the risk of developing anxiety, panic disorder, and depression.
