Researchers are still not entirely certain of the cause of Migraines. The pathophysiology of Migraine is complex, and many theories have come and gone over the years. Improved technology, including imaging technology such as PET scans and fMRI have made it easier to observe a Migraine in progress. Researchers have learned how to use drugs to trigger Migraines, making that research easier to conduct.

For many years, the prevalent theory was the "vascular theory," which was that Migraines occurred due to a fraction of a second of vasoconstriction (constricting or shrinking of blood vessels) followed immediately by vasodilation (the dilation or opening of blood vessels too wide).

The vascular theory of Migraine has gradually lost ground over the years. The week before Thanksgiving, I attended an American Headache Society meeting in Arizona. At that meeting, one of the presentations was Migraine Pathophysiology Update, presented by Dr. Andrew Charles, the Director of the Headache Research and Treatment Program at the David Geffen School of Medicine at UCLA. This presentation included information about dilation of blood vessels and Migraine. Here are some statements from that presentation:

• Dilation of blood vessels is neither necessary nor sufficient for causing Migraine pain.
• Cerebral and meningeal blood vessels are not dilated during spontaneous Migraine or Migraine induced by:
  • Nitroglycerin
  • Sildenafil
• Some drugs that induce significant cerebral vasodilation do not cause Migraine.

and:

• Vasodilation may occur as part of the disorder, but is not required for Migraine pain.

Summary and comments:

That vasodilation may occur during Migraine, but doesn't always and is not required for Migraine pain is a fact that we need to keep in mind when reading material about Migraines, what occurs when we encounter a trigger, and what's happening in the brain during a Migraine attack. It's also something to keep in mind when talking with doctors.

If you're reading a book, magazine, online content, etc., and it says vasodilation is necessary for Migraine or that Migraines are caused by vasodilation, it's old information.

If your doctor says that vasodilation is necessary for Migraine, your doctor is behind in his training and information. In that case, I'd suggest finding a doctor who is more knowledgeable, In such cases, it may well be time to consult a Migraine specialist.

____________
Resources:

Charles, Andrew, MD. "Migraine Pathophysiology Update." Presented at the American Headache Society Scottsdale Symposium. November 19, 2010.

Medical review by John Claude Krusz, PhD, MD

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© Teri Robert, 2010. Last updated November 29, 2010.

All content on this site is physician reviewed by Dr. John Claude Krusz.

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