Migraine

Migraine is a neurological disorder that causes moderate-to-severe headaches, usually on one side of the head. It often comes with nausea, light sensitivity, and sound sensitivity. Some people may also feel dizzy, vomit, or have trouble thinking during an attack. In certain cases, a migraine starts with an aura, which is a strange feeling or vision change before the headache begins.

The frequency of migraine attacks can vary a lot. Some people only have a few attacks a year, while others suffer from chronic migraine with headaches happening very often. Changes in daily routines, like missing meals, not sleeping well, or hormonal shifts, can often trigger an attack. Over time, using pain medicines too often for headaches can actually make migraines worse, leading to something called medication overuse headache.

Scientists believe that migraines happen due to a mix of genetic, environmental, and brain factors that affect nerve cells and chemicals. Managing migraines often includes changing lifestyle habits to avoid triggers, such as managing stress, having regular meals, getting good sleep habits, and exercising. Treatments for mild to moderate migraines can start with over-the-counter medicines like ibuprofen and paracetamol. For more severe cases, triptans are often used, and newer medicines called gepants are now available. Other treatments may include anti-nausea medications and prevention medicines like beta blockers, anticonvulsants, and certain antidepressants.

Migraine affects about 14% of the world's population, or 1.16 billion people, making it one of the most disabling conditions affecting the nervous system. Women are more likely to experience migraines than men, especially beginning at puberty. Migraine frequency often increases after a girl's first period, peaks around perimenopause, and usually decreases after menopause.

Signs and symptoms

Migraines usually cause strong, throbbing pain on one side of the head. People with migraines often feel very sensitive to light, sound, and other senses. The pain can last from a few hours to a few days and can be quite severe.

Migraine attacks can happen in different stages, though not everyone experiences all of them. First, there may be warning signs like mood changes, tiredness, or food cravings up to two days before the headache. Some people see strange lights or patterns before the pain starts. Then comes the headache itself, which can include nausea and a need for a quiet, dark room. After the headache, people might feel tired or have trouble focusing.

Causes

Migraines happen because of a mix of things like genes, the environment, and how the brain works. They often run in families, but it's not because of just one gene. Many genes work together to make someone more likely to get migraines.

Migraines can also happen with other conditions like feeling very sad or worried. This might be because of shared genes or how the brain works.

Genetics

Scientists have found that genes play a big role in whether someone gets migraines. Studies with twins show this. But not all groups of people have been studied enough. It's known that many genes, each adding a small risk, make migraines more likely.

Rare genes can also cause migraines, like in a condition called familial hemiplegic migraine. There are also links to other genetic conditions, but doctors have special ways to tell them apart.

Triggers

Things that might start a migraine are called triggers. These can include feelings, food, sleep, hormones, weather, and too much sensing things like loud noises or bright lights. Triggers can come from inside the body, like stress or not eating, or from outside, like weather changes.

Before a migraine starts, people might feel tired, have trouble focusing, or feel sick. These signs can help someone know a migraine is coming.

Hormonal changes

Women often get migraines more than men, especially because of changes in hormones like estrogen. Migraines can happen more around a woman's period or during certain times of life. Pregnancy can change how often migraines happen too.

Stress

Stress is a well-known trigger for migraines. Learning ways to relax, like through special therapies, can help manage stress and possibly prevent migraines.

Sleep

Not sleeping enough, sleeping too much, or having irregular sleep can trigger migraines. Keeping a regular sleep schedule and good sleep habits can help.

Diet

Skipping meals or not eating regularly can trigger migraines. Some foods and drinks, like alcohol, coffee, or certain cheeses, might also be triggers for some people. Eating regular, balanced meals can help prevent migraines.

Sensory sensitivity

Many people with migraines are very sensitive to light, sound, and smells. This sensitivity can be an early sign that a migraine is coming. Finding quiet, dim spaces can help during a migraine attack.

Light

Being sensitive to light is common with migraines. Bright or flickering lights can make discomfort worse. Staying in a dark room or wearing sunglasses can help.

Sound

People with migraines often hurt more from loud sounds. Keeping quiet and avoiding loud noises can help during an attack.

Smell

Strong smells can be bothersome for those with migraines. Using fragrance-free products and good ventilation can help reduce exposure to strong smells.

Weather

Changes in weather like temperature or air pressure sometimes trigger migraines, but studies don't always agree on this.

Mechanism

Migraine is a complex pain disorder that involves both blood vessels and nerves in the brain’s protective layers, called the meninges. The trigeminal nerve, which is located within the dura mater, helps carry information about pain from the face to the brain. The hypothalamus, a part of the brain, also plays a role by receiving signals from the trigeminal nerve and can influence its activity.

When a migraine begins, changes in the hypothalamus and nearby brain areas can lead to increased activity in the pain pathway. This can cause pain signals to be sent more strongly to the brain. Special chemicals, like CGRP, are released and can cause blood vessels to widen and send more pain signals. These changes lead to the headache and other symptoms that people with migraine experience.

Diagnosis

The diagnosis of a migraine is based on looking at signs and symptoms. Keeping a headache calendar helps track when headaches happen, how long they last, and what symptoms come with them. Migraines can be grouped based on whether a person sees special patterns or feelings before the headache (called aura) or not, and how often they happen.

According to the International Classification of Headache Disorders, doctors usually figure out if someone has migraines by looking at the pattern of headache features and related symptoms, instead of using lab tests or imaging. Neuroimaging tests are not needed to diagnose migraine, but might be used if there are unusual symptoms or problems that make it hard to tell if it’s really a migraine. The American Headache Society says imaging is only needed when there are "red-flag" symptoms or strange findings during an exam.

To diagnose migraine without aura, doctors use the "5, 4, 3, 2, 1 criteria":

• Five or more headache attacks (for migraine with aura, only two attacks are needed)
• Lasting from four hours to three days
• Two or more of these features:
  • Affects one side of the head
  • Throbbing pain
  • Moderate to severe pain
  • Made worse by routine physical activity
• One or more of these:
  • Nausea and/or vomiting
  • Sensitivity to light (photophobia) and sound (phonophobia)

If someone has two of these: light sensitivity, nausea, or can't work or study for a day, migraine is more likely. If a person has four out of five of these features — throbbing headache, lasting 4–72 hours, pain on one side, nausea, or symptoms that interfere with daily life — there is a 92% chance it is a migraine. With fewer than three of these symptoms, the chance drops to 17%.

Classification

Main article: ICHD classification and diagnosis of migraine

Migraine was first classified in 1988 by the International Headache Society (IHS). They updated it in 2004, and a third version came out in 2018. This classification groups migraine with other primary headache disorders like tension headaches and cluster headaches.

Migraine is classified into several groups:

• Migraine without aura — headaches without warning signs before them.
• Migraine with aura — headaches that come with warning signs, which can sometimes happen without a headache or with a different kind of headache.
  • Subtype: hemiplegic migraine and sporadic hemiplegic migraine, where aura comes with weakness.
  • Subtype: migraine with brainstem aura (MBA), where aura includes trouble speaking, dizziness, ringing in the ears, or other brainstem symptoms, but not weakness. Retinal migraine involves vision problems or temporary blindness in one eye.
• Episodic syndromes that may be associated with migraine — conditions often seen in children, like cyclical vomiting, abdominal migraine (stomach pain with nausea), and benign paroxysmal vertigo of childhood (spinning sensation).
• Complications of migraine — unusually long or frequent migraines, or those linked to seizures or brain changes.
• Probable migraine — conditions that look like migraine but don’t fully meet all the criteria.
• Chronic migraine — headaches on at least 15 days a month for more than three months, with at least eight days meeting migraine criteria.

Abdominal migraine

Abdominal migraine is most often found in children, but sometimes in adults. It is diagnosed using criteria from the Rome IV and ICHD III classifications. It includes sudden, repeated attacks of stomach pain that may come with nausea and vomiting. These attacks last at least one hour and can affect daily life. The average attack lasts about 17 hours. Abdominal migraine often happens in people with a personal or family history of typical migraine, and children may develop typical migraine later. Abdominal migraine, migraine, and cyclical vomiting syndrome share similar symptoms.

Differential diagnosis

Other conditions that can look like migraines include temporal arteritis, cluster headaches, acute glaucoma, meningitis and subarachnoid hemorrhage. Temporal arteritis usually happens in people over 50 and causes tenderness on the temples. Cluster headaches cause severe pain around the eyes, nose stuffiness, and tears. Acute glaucoma brings vision problems. Meningitis comes with fever. Subarachnoid hemorrhage starts very quickly. Tension headaches usually affect both sides, aren’t throbbing, and are less disabling.

People with stable headaches that meet migraine criteria generally do not need neuroimaging to check for other brain issues.

Management

Main article: Management of migraine

Managing migraine involves both preventing attacks and treating them when they happen. Preventive treatment helps reduce how often and how bad future headaches might be. This can include changing daily habits like sleeping and eating regularly, staying hydrated, managing stress, and exercising moderately. Avoiding certain foods and too much caffeine can also help. For children and teens, techniques like relaxation and special therapies can lessen migraines without medicine side effects.

When a migraine starts, early treatment works best. Over-the-counter medicines like ibuprofen and paracetamol can help with milder headaches. Stronger medicines are used for more severe pain. It’s important not to use certain medicines too often, as this can lead to more frequent headaches. Other treatments may be used for very bad or long-lasting migraines. Different medicines have been tested to see which work best and have the fewest side effects.

Prognosis

For people who have occasional migraine headaches, the right mix of medicines can help control the headaches and reduce their effect on daily life. Many people with migraine don’t get a proper diagnosis, and fewer than half seek help from a doctor.

Repeated migraine pain can cause changes in the brain, and some people may develop chronic migraine, where headaches happen very often. This change affects about 3% of migraine sufferers each year, leading to 8% having chronic migraine at any time.

Migraine can be more complex for women, especially those who experience aura — visual disturbances before a headache. Migraine with aura is linked to a higher risk of certain health issues, like stroke, especially in women using estrogen-containing birth control. However, migraine without aura does not seem to increase the risk of these health problems. Preventative treatment can help lower the risk of strokes in those with migraine with aura.

People with migraine, especially women, may sometimes have more white matter lesions in the brain, though the meaning of these findings is not fully understood.

Epidemiology

Migraine is a common condition that affects many people. About one-third of women and one-fifth of men experience it at some point in their lives. Worldwide, roughly 1.16 billion people have migraines in any given year.

In the United States, around 18% of women and 6% of men have migraines each year. In Europe, the numbers range from 12% to 28% of people having migraines at some point. Migraine is slightly less common in Asia and Africa compared to Western countries. The chance of having migraines increases around the time of puberty and stays high until after age 50. Before puberty, boys and girls are equally likely to have migraines, but after puberty, women experience them more often than men.

Economic impact

Migraines cause a lot of money to be spent on medical care and lost work time. In 2012, they cost about 50–111 billion euros each year in Europe. By 2017, the United States spent around 78 billion US dollars on migraines. People with chronic migraines cost even more. Even when people go to work during a migraine, they are less effective, and families also feel the effects.

Research

Migraine is a big problem for many people, but it does not get as much money for research as it should. In the US in 2019, migraine research received only 7.8% of the funding it needed based on how much it affects people. In Europe, migraine was the brain disease that received the least funding compared to how much it costs the economy.

History

An early description that matches migraine is found in the Ebers Papyrus, written around 1500 BCE in ancient Egypt.

The word migraine comes from the Greek word for "pain in half of the head." In 200 BCE, writings from the Hippocratic school of medicine talked about the visual changes that can happen before a headache and some relief through vomiting.

A doctor named Aretaeus of Cappadocia divided headaches into three types. Another doctor, Galen of Pergamon, thought the pain came from the head's covering and blood vessels. In 1887, a French librarian split migraine into two types: migraine with visual changes and migraine without.

Many treatments have been tried for migraine. In 1868, people started using a substance from a fungus called ergot. A medicine called ergotamine was isolated in 1918 and used for migraine in 1925. In 1959, a new medicine called methysergide was made. The first triptan medicine, sumatriptan, was developed in 1988. During the 20th century, better studies helped find and confirm effective ways to prevent migraine.