Medical Monday: What Causes a Migraine, and What Relieves the Pain?

What Happens During a Migraine?

The migraine process starts with some sort of trigger. Triggers vary from person to person, but common ones include changes in sleep patterns (too much or too little); environment (weather, bright lights, odors, or pollution); stress; diet (skipping meals, specific foods, medications); alcohol (especially red wine, beer, and sherry); caffeine; and hormonal changes—mostly fluctuations in estrogen levels.

Once the migraine is triggered, people will generally have a sense that a migraine is coming on, sometimes up to 24 hours prior to the start of the headache. This period is called the “prodrome.” The prodrome is likely caused by some aberrant electrical firing in the brain, producing the vague sense that something is off. These prodromes generally do not change: one person may experience significant hunger; another may feel extremely fatigued or even just have a premonition that a headache is about to start.

This aberrant firing leads to the spread of electrical activity to other regions of the brain (figure 1.1). The spreading electrical activity can be experienced as an aura, as described above, or simply an intensification of the prodromic sensations (figure 1.2).



As this electrical activity spreads, the brain releases chemicals that lead to the dilation of blood vessels in the meninges, a membranous covering that surrounds the brain (figure 1.3). With the increased blood flow, nerve fibers in the meninges that branch off of the trigeminal nerve (the nerve responsible for sensation in the face and scalp) are activated and pain signals travel back through the trigeminal system (figure 1.4). Over-stimulating the nerves responsible for relaying touch from the face (e.g. brushing the hair, touching the face) can lead to additional pain.

Without intervention, these painful attacks can last from 4 to 72 hours, and occasionally even longer.

Hormonal Effects on Migraines

Based solely on the significantly higher number of women suffering from migraines compared with men, it appears that female sex hormones have a significant influence. Further evidence of the impact of female hormones on migraine incidence comes from the most common age range for migraneurs: 15 to 55 years old, corresponding roughly to menarche (first period) and menopause. In fact, before puberty, girls and boys have an approximately equal likelihood of having migraines.

In one study of women going through the menopausal transition, roughly 60 percent of women with headaches (both migraine and tension-type) had no more headaches after menopause, and only 14 percent of postmenopausal women reported migraines. Additional population studies saw similar findings.

What you describe—premenstrual migraines—is a significant subset of migraines as a whole. Four to twelve percent of women with migraines have them only in the two days before or after the start of the period; an additional 50 percent of migraineurs have menstrually related migraines, or migraines that occur more frequently around the start of the period, but can occur at any time during the cycle.

Next page: Treatment of Migraines

Join the conversation

This site uses Akismet to reduce spam. Learn how your comment data is processed.

  • Stephanie Weaver, MPH June 9, 2015 at 1:35 am

    This is an excellent and informative post. I’ve been researching lifestyle approaches to reducing migraine for a year. The best book currently available on the migraine diet is Dr. David Buchholz’ book: Heal Your Headache.

    I’m working on one, with 125 recipes, but it will be at least a year before it’s available.