Migraine

Definitions & Key takeaways

A migraine is a type of headache that presents with recurrent episodes of (usually) unilateral, throbbing headaches. It may be accompanied by sensitivity to light, nausea and vomiting, and a preference for a quiet environment.

Sometimes there can be an aura where people experience strange smells, lights, visual disturbances, or even hallucinations before the onset of the migraine. The cause of migraine is not yet known, but it is believed to have a genetic predisposition, and risk factors such as alcohol, hormonal changes in women, fasting, disorganized sleeping patterns, etc.

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Introduction0:00–0:31

Migraine is a primary type of headache, meaning it happens on its own, not because of something like a head injury or tumor.
The word migraine comes from Greek and means half of the skull, because the pulsating pain often affects just one side of the head.
Now, let's take a moment to talk about pain. Imagine you're trying to hit a nail with a hammer, but accidentally smack your thumb instead.
Special nerve cells called pain receptors immediately detect the hit and convert it into an electrical signal that travels up your spinal cord to your brain, which interprets the signal as pain.

Physiology0:31–1:07

Interestingly, the brain itself doesn't have pain receptors, so it doesn't actually feel pain. So when you have a headache, it's not the brain that hurts, it's the structures around it, like the venous sinuses and the meninges, especially the dura mater.
Now the innervation of these structures comes from the trigeminal ganglion, which sends C fibers and A delta fibers along the trigeminal nerve, particularly the ophthalmic branch.

Tension headaches1:07–1:39

Together these fibers form part of the trigeminal vascular system, which connects the trigeminal nerve to the blood vessels and meninges.
When this system is activated, the C fibers release calcitonin gene-related peptide, or CGRP, a key chemical involved in pain signaling and inflammation.
Interestingly, CGRP receptors are located on A delta fibers, allowing local crosstalk between these fibers. When CGRP binds to receptors on nearby A delta fibers, it makes them more responsive to stimuli, enhancing the transmission of pain signals.

Migraines1:39–3:44

While the exact cause of migraine remains a mystery, we think that the trigeminovascular system and CGRP play a major role.
During a migraine episode, C fibers release CGRP, stimulating CGRP receptors on A delta fibers and vascular smooth muscle cells of the dura mater.
Eventually this leads to vasodilation and promotes neurogenic inflammation, contributing to migraine pain. Also, migraines tend to run in families, suggesting a genetic predisposition, because many individuals with migraines have relatives who also experience the condition.
Besides genetics, migraines are about twice as common in biological females than in biological males. For some individuals, a migraine doesn't start with pain, but with a warning phase called an aura.
This happens because of abnormal ion channel activity in cortical neurons, which triggers a process known as cortical spreading depolarization.
During this process, a slow wave of neuronal depolarization moves across the cerebral cortex, followed by a period of hyperpolarization and temporary suppression of neuronal activity.
This wave of electrical changes, also called the spreading depression of Lia, results in temporary sensory disturbances known as auras.
These include visual changes like flashing lights or blind spots, tingling sensations, and speech difficulties. Now, several factors are known to trigger migraine episodes.
One major group includes daily habits, such as eating a high carbohydrate diet, physical inactivity, and stressful life events.

Cluster headaches3:44–4:36

It's worth mentioning that when psychological stress is involved, migraine attacks often occur after a stressful period, typically at the end of the work week, like on a Friday evening, or following a challenging pathology exam.
The second group of triggers covers hormonal changes. For example, estrogen containing oral contraceptives can worsen migraine symptoms.
Additionally, migraines tend to become more frequent during certain phases of the menstrual cycle. Now, there are several different types of migraines.
First, we have the common migraine, also known as migraine without aura. In this case, migraine usually presents as a one-sided pulsating headache that gets worse with movement.
It can last up to 72 hours, and is often accompanied by nausea, vomiting, and sensitivity to light, known as photophobia, as well as sensitivity to sound, known as phonophobia.

Diagnosis4:36–4:47

Usually before a migraine episode, patients experience a prodrome of malaise, irritability, or behavioral change that might last for some hours or even days.

Treatment4:47–5:55

You can use the pneumonic pound to remember the most important features of migraines. P stands for pulsatile pain, O for one-sided, U for lasting up to 72 hours, N for nausea and vomiting, and D for disabling intensity.
Next, we have migraine with aura. In this type, temporary neurological symptoms appear before or along with the headache.
For example, a person can experience visual disturbances, including shimmering silvery zigzag lines that gradually float across the visual field.
These can last up to 40 minutes and might leave behind a temporary visual field loss known as scotoma. Next, they might report sensory symptoms, such as tingling or numbness that spreads from one part of the body to another.

Summary5:55–9:53

Finally, there might be speech difficulties, which can be mistaken for a transient ischemic attack or stroke. In rare cases, a person may experience an aura without the subsequent headache, known as a migraine aura without headache, or simply silent migraine.
Although migraines usually occur in episodes lasting up to 72 hours, in severe cases they can appear in a more malignant form.
In this type, individuals experience daily headaches with minimal pain-free intervals. They can also develop temporary cognitive symptoms such as difficulty concentrating, memory problems, and mental fog, which can significantly disrupt daily functioning and quality of life.
And if a person reports headaches 15 or more days per month for at least 3 months, with at least 8 days showing migraine features, we call this chronic migraine.
These headaches can include both migraine and tension type headaches, which represent a constant mild to moderate pressure or tightness around the head.
Risk factors for chronic migraine include obesity, overusing acute headache medications, drinking too much caffeine, stress, and having sleep disorders.
Now, to diagnose migraine, a person must have at least 2 of the following 4 features. These include a one-sided headache, pulsating pain, moderate to severe intensity, and headache aggravated by movement.
Also, they must present with at least one of the associated features, such as nausea or vomiting, photophobia, and phonophobia.
If abnormal neurological signs are present, be sure to order a brain MRI to rule out other conditions like infections, tumors, or structural abnormalities.
Finally, let's look at how to prevent and treat migraines. Prevention focuses on reducing exposure to common triggers, such as getting enough sleep, staying physically active, managing stress, and avoiding estrogen-based contraceptives.
However, when a migraine attack does occur, pain relievers like acetaminophen, aspirin, or other NSAIDs can help. For more severe attacks, triptans such as sumatriptan are effective at stopping the migraine.
For frequent migraines, consider prophylaxis with vasoactive medications, certain antidepressants, or even anti-epileptic medications.
Lastly, anti-CGRP monoclonal antibodies show promise in preventing migraines. All right, as a quick recap.
Migraine is a type of primary headache that typically presents with a one-sided pulsating headache of moderate to severe intensity, often worsened by physical activity.
It can last up to 72 hours, and is often accompanied by nausea, vomiting, and increased sensitivity to light and sound. During a migraine attack, levels of CGRP rise, contributing to neurogenic inflammation and vasodilation.
Several risk factors can increase the risk of migraine, including a high carbohydrate diet, lack of physical activity, and stress.