A brain aneurysm, sometimes called a cerebral aneurysm, is a weak spot in a brain artery. The weak spot creates a balloon that fills with blood.
The walls of the artery are weaker near an aneurysm, which means that the aneurysm can break open, or rupture. A ruptured aneurysm is a life threatening condition that can cause serious brain injuries or stroke. However, not all aneurysms rupture.
People with an aneurysm may need ongoing monitoring to ensure that it is not growing. A doctor may need to remove a larger aneurysm.
In this article, we provide an overview of brain aneurysms, including the types, symptoms, causes, complications, and treatments.
According to the National Institute of Neurological Disorders and Stroke, brain aneurysms affect an estimated 3–5% of people in the United States during their lifetime. They are more common in females than in males and tend to affect adults between the ages of 30 and 60 years.
The Brain Aneurysm Foundation state that ruptured brain aneurysms account for just 3–5% of all new stroke cases. If an aneurysm does rupture, it is fatal in about 40% of cases, with 15% of people dying before they reach the hospital.
Doctors classify aneurysms according to the shape of the weak spot in the artery.
There are three main types of aneurysm:
The size of an aneurysm is a significant predictor of whether or not it will rupture:
Some aneurysms grow over time, and a small number grow rapidly. Growth, especially rapid growth, increases the risk that the aneurysm will rupture.
Larger aneurysms are more likely than smaller ones to cause symptoms before they rupture, but most aneurysms do not cause any symptoms during this stage.
When people with an unruptured aneurysm do experience symptoms, they may include:
Sometimes an aneurysm leaks before it ruptures. Doctors call this a sentinel rupture or sentinel bleed.
Sentinel ruptures sometimes cause sentinel headaches. A sudden, severe headache — especially one that does not fit a person's usual headache pattern or that is worse than any other headache they have ever had — could be a sentinel headache.
Other symptoms of a sentinel rupture include:
Anyone who has symptoms of an aneurysm should seek immediate medical care. If a person has previously received a diagnosis of an unruptured aneurysm, it is essential that they make the emergency care team aware of this.
Brain aneurysms are more common in females than in males and more likely to affect adults between 30 and 60 years old. In addition, genetic and lifestyle factors that weaken the walls of blood vessels greatly increase the risk of aneurysm.
Risk factors for brain aneurysms include:
While brain imaging techniques, such as CT scans and MRI scans, can help doctors diagnose some aneurysms, an angiogram allows them to make a definitive diagnosis.
To perform a cerebral angiogram, a doctor will insert a small, thin tube called a catheter into a blood vessel in the groin and direct it into the blood vessels of the brain under X-ray guidance. There, they will inject a dye that makes it easier to see the blood vessels and any unusual structures.
An angiogram can help the doctor assess the size and severity of the aneurysm, as well as its type. This information helps them make appropriate treatment recommendations.Causes and treatments of aneurysm Aneurysms can also affect arteries in other parts of the body. Learn more about their causes, symptoms, and treatment here. Read now
Not all brain aneurysms require immediate treatment. If the aneurysm is small, a doctor may recommend monitoring it over time.
The best treatment option will depend on the following factors:
A person with a family or personal history of aneurysm rupture may need treatment even if the aneurysm is small.
A doctor may recommend an endovascular procedure or surgery to treat the aneurysm.
During an endovascular procedure, a surgeon inserts a catheter through the groin, then navigates to the aneurysm. Next, they pack the aneurysm with metal coils or a stent to redirect the blood flow. Doing this stops blood from flowing into the aneurysm, which prevents rupture.
Surgery for an aneurysm requires an operation on the brain, which will take place under general anesthesia. This procedure usually requires a person to spend several days in the hospital, and it may be necessary to shave the person's head. During the operation, a surgeon clips the aneurysm to prevent blood from flowing into it.
Following this treatment, most aneurysms do not reoccur.
Both endovascular treatment and brain surgery come with risks, including:
An unruptured aneurysm typically does not cause any complications. However, a ruptured aneurysm can cause serious, lasting health conditions, and it can be fatal.
Possible complications of a ruptured brain aneurysm include:
Some aneurysms are not preventable. However, a healthful lifestyle can support blood vessel health and reduce the risk of an aneurysm.
People can reduce their risk using the following strategies:
People who have unruptured aneurysms should talk to a doctor about how to minimize the risk of rupture. Ongoing monitoring can reduce this risk and guide a doctor's treatment decisions.
An aneurysm is not a stroke, but it can cause one. When an aneurysm bursts, this deprives the brain of blood, potentially leading to a stroke.
The symptoms of a ruptured aneurysm and stroke are similar but not identical. While both cause neurological symptoms, such as dizziness or blurred vision, aneurysms also typically cause headaches.
Both conditions are serious medical emergencies that demand immediate treatment. Therefore, a person should see a doctor whether they have symptoms of an aneurysm, stroke, or both.
Learn more about the differences between aneurysms and stroke here.
Among people who survive an aneurysm rupture, about 25% die from complications within 6 months, and 66% have lasting neurological damage.
For this reason, it is important to identify and treat aneurysms as early as possible. Prompt medical care increases a person's chances of survival.