When is a headache more than just a headache? A sudden and intense headache, or unusual headaches that persist or recur without warning, might be a sign of a brain aneurysm (cerebral aneurysm).
This condition occurs when one or more blood vessels in the brain weaken, causing the walls of vessels to bulge or balloon. An aneurysm can tear or rupture, leading to stroke or bleeding around the brain.
"Cerebral aneurysms are scary," says Dr. Alex Hoang, a neurosurgeon at Houston Methodist. "We think of it as a ticking time bomb, because if it ruptures, it could be deadly."
Not all brain aneurysm ruptures are fatal, and millions of people live with small, undetected aneurysms. The keys to prevention and survival are understanding the risk factors, recognizing the warning signs and seeking medical help quickly.
"Aneurysms can vary in size, location and risk of rupture," says Dr. Kurt Yaeger, also a neurosurgeon at Houston Methodist. "Not all aneurysms need to be treated — some can be safely observed. In general, though, it is safest and easiest to treat unruptured aneurysms, which makes consulting a specialist after a brain aneurysm diagnosis very important."
The signs of a brain aneurysm
A brain aneurysm can develop slowly with no noticeable symptoms. If symptoms do appear, they will vary depending on the location in the brain and the size or shape of blood vessels involved.
Symptoms of an unruptured brain aneurysm
A small area of weakened blood vessels might be present for years without being detected. Researchers believe that 1 in every 50 people in the U.S. — nearly 7 million Americans — live with an unruptured cerebral aneurysm.
In some cases, a care team will spot an aneurysm while a patient is getting imaging tests for an unrelated reason, such as an accident-related head injury.
An unruptured aneurysm can trigger neurological problems, such as headaches or facial weakness or numbness. Patients might have eye problems or pain that lead them to the doctor. The bulging area can press on parts of the brain that control one or both eyes, causing discomfort.
"I have seen patients that had a droopy eyelid, double vision and a dilated pupil," says Dr. Hoang, "and those were signs of a large aneurysm compressing one of the nerves that controls function in the eye."
Symptoms of a leaking brain aneurysm
As an aneurysm grows, weakened vessels can leak blood. This can lead to recurring headaches, known as sentinel headaches, that grow increasingly intense. Like a military sentinel on watch, the brain gives out warnings that a serious problem may be lurking.
Patients who get sentinel headaches often describe them as having no focal point, with pain not associated with a specific activity, food, medication or illness such as the flu. Sentinel headaches might appear days or weeks before a ruptured aneurysm, but not all patients will have these warning signs.
If leaking blood reaches the fluid surrounding the spinal cord, it can cause neck stiffness or pain, nausea or vomiting, or sudden drowsiness. If you have a sudden, severe headache, especially with other symptoms, seek immediate medical help.
Symptoms of a ruptured brain aneurysm
Nearly every patient who survives a ruptured aneurysm reports a thunderclap headache — often described as the worst headache of their life, with sudden pain so intense it's almost immediately debilitating. In fact, a thunderclap headache that lasts for five minutes will typically peak within just 30 seconds.
A thunderclap headache might also cause nausea, vomiting, neck pain or stiffness, double vision, sensitivity to light or loss of consciousness.
A ruptured cerebral aneurysm is always a medical emergency. The sudden rush of blood into the brain (subarachnoid hemorrhage) is often fatal. Survivors face serious, long-term brain injury. Call 911 if you or someone near you has these symptoms or anything similar to a stroke.
"Time is of the essence in treating ruptured aneurysms in order to prevent further stroke," Dr. Yaeger stresses. "We consider this an emergency and would want to care for you in the hospital as soon as possible."
The importance of early detection
While most people understand that immediate medical help is key with heart attack or stroke, signs of a brain aneurysm aren't as well known. Research shows that every 18 minutes, someone in the U.S. has a ruptured brain aneurysm. The consequences can be dire.
"Brain aneurysm rupture is a medical emergency," says Dr. Hoang.
With timely treatment, there is a much lower risk of severe complications such as seizures, blood clots, infections and bleeding. The chance for a successful recovery increases with care from physical, occupational and speech therapists. "About 50% of patients need advanced care to recover," Dr. Hoang adds.
Risk factors for brain aneurysms
As with many brain conditions, there is no single cause of brain aneurysm. Patients often have underlying factors, such as:
- Family history
- History of tobacco use
- Uncontrolled high blood pressure
- Head injury, infection or another acute condition
- Atherosclerosis, which narrows arteries in the brain
- Circulatory disorders
"An aneurysm typically doesn't go away, but you can limit the risk of rupture by modifying your risk factors — stopping smoking and keeping your blood pressure under control, for instance," Dr. Yaeger explains. "For patients with small aneurysms, monitoring via annual screening tests is critical for ensuring the aneurysm hasn't grown."
How to monitor your health
If you are at risk of a brain aneurysm or have one, work with your doctor to control your blood pressure. Uncontrolled blood pressure is a major risk factor for developing an aneurysm and is associated with poor outcomes after rupture. Controlling blood pressure can prevent some ruptures. Some blood pressure medications can reduce the risk of rupture by 8%.
Family history is also key. If you have two family members — say a parent or an aunt or uncle — who had an aneurysm, there is about a 20% risk it could be genetic. Talk with a doctor about genetic testing. At least 17 genetic variants are associated with cerebral aneurysm, and some are linked to more complications or multiple ruptures.
When to see a doctor for a brain aneurysm
Seek emergency care for a thunderclap headache or other debilitating symptoms, and talk with a health care provider if you have unusual or persistent symptoms. You may need a referral to a specialist at Houston Methodist's Cerebrovascular Center for advanced care.
If you are diagnosed with an unruptured or leaking aneurysm, or if genetic testing shows a familial connection, you may also be eligible to participate in a neurology clinical trial for new therapies that aren't available at other institutions.
