Understanding the Link Between Migraine and Vomiting

Migraine is a neurological disorder that is characterized by excruciating, pounding pain, usually on one side of the head. For some people, migraine pain can be so severe that it can disrupt their everyday life. In many cases, migraine pain is also accompanied by nausea and vomiting. Research has shown that vomiting may alleviate or even halt migraine pain. In fact, some people with migraine try to induce vomiting in order to get relief from head pain. Read on to understand the link between migraine and vomiting.

Migraine is a neurological or cerebrovascular disorder that is characterized by extreme, throbbing, or pounding pain, usually only on one side of the head. Migraine is marked by repeated symptoms that typically include nausea, vomiting, sensitivity to touch, smell, sound, or smell, along with a headache. Migraine attacks can hit suddenly without warning, or they may be preceded by an aura, or the common symptoms associated with migraine that people experience a few hours before the migraine episode.^{(1, 2, 3, 4)}

The pain of a migraine episode can often be debilitating in many people, disrupting their day-to-day lives. In most cases, migraine headache is also accompanied by nausea and vomiting. Research has also shown that in many instances, vomiting might relieve or even stop the migraine pain. In fact, many people with migraine try to induce vomiting in order to prevent headaches. Let’s look at the association between migraine and vomiting.^{(5, 6)}

It is not exactly known as to why vomiting stops migraine pain in some people, though there are several explanations behind this.

A study done in 2013 hypothesized many reasons behind why vomiting may stop migraine pain.⁽⁷⁾

1. End-of-a-Migraine Hypothesis: Some experts believe that vomiting represents the final stage of migraine progression. For some people, vomiting is simply a feature that accompanies a migraine attack. It is not entirely understood why a migraine episode ends with vomiting. During a migraine attack, the gut slows down or may even stop moving, a process known as gastroparesis. As the migraine episode ends, the gut starts to move again, and the vomiting is one of the features that mark the working of the gastrointestinal tract again.^{(8, 9)}
2. Decrease in Sensory Input Hypothesis: Vomiting is believed to induce pain-relieving effects by getting rid of the sensory input to the gut. Conversely, once the gastrointestinal tract eliminates itself of the sensory stimulus, it helps boost a feedback loop to halt the migraine.⁽¹⁰⁾
3. Complex Interaction Hypothesis: The pain of migraine may stop due to the interactions that take place between the various nervous systems in the body. This theory is based on the fact that a migraine attack is a complicated interaction between the central nervous system, the enteric nervous system that is located in the gut, and the autonomic nervous system. In this theory as well, vomiting is observed to be the final process of these different interactions, and vomiting marks the shutting down of the migraine attack.⁽¹¹⁾
4. Vagus Nerve Hypothesis: Another hypothesis revolves around the vagus nerve, which is a cranial nerve that gets stimulated by the vomiting. This vagal stimulation can often bring about a break in migraine pain. This can be done with the help of several prescription medications that are categorized as vagal nerve stimulators that have been cleared by the Food and Drug Administration for the treatment of a migraine episode.^{(12, 13)}
5. Neuropeptide Hypothesis: Vomiting may induce certain involuntary chemical effects that help reduce migraine pain. One example is the release of vasopressin, also known as the hormone arginine-vasopressin (AVP). Arginine-vasopressin has long been associated with the relief of migraine.^{(14, 15)}
6. Peripheral Vasoconstriction Hypothesis: Vomiting is also believed to trigger involuntary vascular effects that help alleviate migraine pain. Vomiting causes peripheral blood vessel vasoconstriction, which is said to decrease blood flow to the pain-sensitized blood vessels, thus helping reduce migraine pain.⁽¹⁶⁾

The 2013 review paper suggested that vomiting can help relieve the symptoms of a migraine headache because of the following reasons:⁽³⁾

• Vomiting releases certain chemicals, like endorphins, that help relieve pain.
• Changes in blood flow to help decrease inflammation and pain.
• Vomiting happens at the end of a migraine attack, causing a decrease in symptoms.

An older study from 1986 showed that vomiting acts as a trigger for the release of endogenous opioids. Endogenous opioids are a type of endorphins that help reduce feelings of pain.⁽¹⁷⁾

As mentioned above, the vagus nerve, which is a part of the parasympathetic nervous system, is also believed to play a role.⁽¹⁸⁾ Vomiting can interact with the vagus nerve in a manner that helps alleviate the pain. In fact, vagus nerve stimulation can also induce vomiting, thus relieving migraine headache pain, which is why doctors also use vagus nerve stimulation implants to ease pain in people who have frequent migraine headaches.

Nausea is one of the most common symptoms of migraine headaches. A study in 2013 showed that over 90 percent of people who have migraine headaches experience nausea, while 70 percent of them experience vomiting.⁽¹⁹⁾ The study further suggested that having nausea and vomiting along with migraine headaches was a sign that the person is at a risk of migraine headaches.

However, experts worldwide still remain unclear as to why exactly migraine headaches cause nausea. One possible reason behind this is believed to be the brain activity that causes the headache and also triggers nausea.

In the majority of people, migraine episodes are often accompanied by an aura, also known as prodrome.⁽²⁰⁾ Prodrome is the phase that shows manifests before or during the migraine attack, and it is characterized by food cravings, mood swings, nausea, vomiting, difficulty concentrating, visual disturbances, and sensitivity to sound and light among other symptoms. This phase is typically the period of symptoms that signifies that a migraine attack is oncoming.

In some people, the aura phase might end with vomiting or fatigue and not necessarily cause the follow-up headache typical of migraine attacks.

Another possible explanation behind the association between nausea, vomiting, and migraine could be because of the gut and brain connection. Since the gut and brain are connected and able to communicate with one another, it is expected that if something is happening in the brain, there will be some reaction in the gut as well. A good example of this gut-brain connection is the feeling of butterflies in the stomach when you feel nervous or anxious.⁽²¹⁾

• Understanding The Gut-Brain Axis: Communication between the gut and the brain is known to be bidirectional, meaning that not only can the brain send messages to the gut, but the gut can also send messages to the brain. This is referred to as the gut-brain axis, and it links the central nervous system to the enteric nervous system present in the gut through the vagus nerve. In fact, the vagus nerve also runs right from the brain to the gut.^{(22, 23)}
• Abdominal Migraine: Most people have never heard of an abdominal migraine. This is a type of migraine that usually only happens in children. Nausea and vomiting are the most signs of this condition, while the migraine pain, in this case, is centered in the stomach instead of the head. Children who are prone to experiencing abdominal migraine usually end up having migraine attacks once they grow up.^{(24, 25)}
• Cyclical Vomiting Syndrome: This is also a variant of migraine that is commonly observed in children. A severe episode of nausea and vomiting, in this case, can last for a couple of hours to even a few days. It is followed by a symptom-free period. Episodes of cyclical vomiting syndrome may occur on a regular basis and tend to follow a pattern. It is also possible for these episodes to occur randomly.^{(26, 27)}

Nausea and vomiting are some of the most common symptoms of migraine, along with migraine headaches. Migraine attacks, when combined with these symptoms, can feel excruciating and debilitating, preventing you from leading a normal life. It is interesting to note that in many cases, vomiting helps relieve or even completely stop migraine pain. While the reason for this is not entirely understood, there are several hypotheses experts are exploring that seem to hold promise.

If you also experience nausea and vomiting along with migraine headaches, you should consult your doctor, and they will be able to help you find relief with the right type of migraine treatment.

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