A person may experience intense thunderclap headaches if a brain aneurysm fully ruptures. These last for at least 5 minutes, although they usually peak within 30 seconds.

A brain aneurysm is a compromised spot on a brain artery. This spot gradually fills up with blood, bulging out, and sometimes rupturing.

Whether ruptured or not, an aneurysm can cause painful headaches.

This article looks at the main features of brain aneurysm headaches, including how long they usually last.

It also looks at both brain aneurysm symptoms, compares brain aneurysm headaches and migraine, and discusses seeking medical attention.

A woman lying in bed wondering how long her brain aneurysm headache will last. -2Share on Pinterest
Guido Mieth/Getty Images

As the National Institutes of Health (NIH) explain, most smaller brain aneurysms are asymptomatic.

However, larger brain aneurysms can cause headaches. Brain aneurysms always cause headaches when they rupture.

Unruptured brain aneurysms can cause chronic headaches. When a brain aneurysm slightly ruptures, a sudden and severe headache may result. Doctors call them “sentinel headaches.”

These are different from the intense thunderclap headaches that happen when the artery is fully ruptured.

Learn more

Learn more about brain aneurysms, their causes, and how to prevent them.

Unruptured vs. ruptured

According to the NIH, large and unruptured brain aneurysms sometimes press again nerves.

This can cause pain above and behind the eye. Indeed, some scientists estimate that chronic headaches affect between 18–36% of people with an unruptured brain aneurysm.

When brain aneurysms rupture fully, large volumes of blood leak into the brain. As a 2022 review explains, this always suddenly causes an extremely severe headache. Doctors call these “thunderclap headaches.”

People who have had thunderclap headaches describe them as the most painful headaches they have ever experienced.

Thunderclap headaches always reach peak intensity within 1 minute, although this typically happens within 30 seconds. They last for a minimum of 5 minutes.

Sometimes, a brain aneurysm will burst only slightly, causing relatively small blood leaks. Doctors call these “warning leaks” because they can precede a full rupture.

This can cause a sudden but less intense headache. Doctors call them “sentinel” headaches.

In around 30–50% of full brain aneurysm ruptures, the affected individual reports having experienced a sentinel headache, between 6 and 20 days prior.

Because brain aneurysms affect the brain, they can cause a wide variety of problems, when ruptured or unruptured.

The NIH details signs and symptoms of a brain aneurysm, besides headaches. When unruptured, these include:

Some signs of a ruptured brain aneurysm include:

Ruptured brain aneurysms can also cause heart attacks.

Migraine is a disorder that causes episodes of intense headaches.

Because there are similarities between migraine headaches and brain aneurysm headaches, doctors who diagnose one condition must carefully rule out the other.

However, there are also significant differences between these types of headaches.

The following table compares brain aneurysm headaches with migraine headaches.

DurationSeverityAssociated symptomsLocation
Migraine headachesMost migraine episodes last 4–72 hours. Some can last days at a time. They typically come on fairly slowly.Mostly mild to severe, although some migraine headaches can be extremely debilitating.Headache episodes commonly accompany symptoms like nausea, sensitivity to light, and sensitivity to sound. They typically affect only one side of the head.
Unruptured brain aneurysm headacheResearch suggests that these headaches can be chronic. They can last between several minutes, to several days.Mostly moderately severe.Causes symptoms similar to those of migraine headaches.These headaches also typically affect only one side of the head.
Ruptured brain aneurysm headacheThese headaches come on very quickly. They last for at least 1 minute and may persist until successful treatment.Extremely severe.These can come with nausea and sensitivity to light.In around 30% of cases, these headaches affect only one side of the head.

A ruptured brain aneurysm is a serious medical emergency.

The NIH states that anyone who experiences a severe and sudden headache should seek immediate medical attention. This is especially true if the headache comes with other symptoms of brain aneurysm rupture.

Individuals with symptoms of unruptured brain aneurysms should also seek medical advice.

This section answers some frequently asked questions about brain aneurysms.

Does a headache from an aneurysm go away?

Yes, but not always.

Even with treatment, around 40% of people with an unruptured brain aneurysm will experience long-term chronic headaches.

Research shows similar figures for people who survive a brain aneurysm rupture.

Can unruptured aneurysm headaches come and go?

Yes, although they can also be more constant.

Brain aneurysms can cause many different types of headaches.

An unruptured brain aneurysm can manifest as recurrent or chronic headaches. Even with successful treatment, many people who have had an unruptured brain aneurysm will continue to experience these headaches.

When a brain aneurysm ruptures, this brings on a sudden, severe headache. Partial ruptures induce sentinel headaches, while full ruptures bring on a thunderclap headache. The latter are more intense, and always peak within 1 minute. However, they last for a minimum of 5 minutes.

A ruptured brain aneurysm is a medical emergency. Anyone with a sudden and severe headache should immediately seek medical advice.