Summary of Migraine
Transcript for Migraine
Content Reviewers:Rishi Desai, MD, MPH, Yifan Xiao, MD, Evan Debevec-McKenney, Antonella Melani, MD
Headaches are a type of terrible pain in the head and neck, and there are two main types.
The first are called primary headaches, and they’re more common. These are chronic or recurrent headaches, that account for over 90% of all headaches.
Some examples, are migraine headaches, tension headaches, and cluster headaches.
The second type are called secondary headaches, and these are acute headaches from a specific underlying cause like a serious head injury or a brain tumor.
So normally, throughout the body, there are special neurons that act as pain receptors.
These neurons convert a painful stimulus into an electrical signal that conveys the feeling of “pain” to the brain.
The brain itself does not have pain receptors, but nearby tissues in the head and neck like the blood vessels, meninges, and muscles do have pain receptors.
These pain receptors might be stimulated by a variety of things such as blood vessel spasm like in vasculitis, increased pressure like from a tumor, inflammation like in meningitis, or increased muscle tension like in temporomandibular disorder.
That helps explain the pain in secondary headaches.
Now, in primary headaches the exact mechanisms are unknown.
Tension headaches are the most common primary headache.
It’s called a tension headache because it feels like a band squeezing down on the head applying constant pressure or tension on it.
The pain is mild to moderate, can last a few hours, and usually there are no associated symptoms.
Migraines are the second most common primary headache.
They’re often preceded by symptoms like irritability, depression, and fatigue that can begin hours to days before the headache itself.
Sometimes there can be an aura where people experience strange smells, lights, visual disturbances, or even hallucinations before the onset of the migraine.
The migraine itself usually feels like a pounding or pulsating, typically localized to one side of the head and can last from hours to days.
As if this was not bad enough, these headaches tend to come with nausea and vomiting, irritability, and pain or discomfort with lights, sounds, and smells called photophobia, phonophobia, and osmophobia, respectively.
During childhood, individuals can have nausea and vomiting without the headaches; and that’s called an abdominal migraine.
After a migraine is over, it can leave people feeling sore at the location of the pain and generally fatigued.
To remember the main features of migraines, you can use the mnemonic POUND, where P stands for pulsatile headache, O stands for one-day duration, U stands for unilateral, N for nausea, and D for disabling.
Although the underlying mechanism causing migraines isn’t well understood, there are some clues.
Concentrations of the neurotransmitter, serotonin, increase during the aura, triggering vasoconstriction, and then decrease to lower-than-normal levels during the migraine attack, triggering vasodilation. This change in the blood vessel size may be a trigger for pain receptors, causing the headache.
The initial vasoconstriction may also trigger cortical spreading depression, which is a phenomenon when the brain becomes hypersensitive to certain stimuli like lights, sounds, and smells.