Key takeaways

  • A stroke occurs when the brain does not get enough blood, often due to a blockage. An aneurysm is a bulge in a blood vessel wall that can burst and cause bleeding in the brain.
  • While some symptoms overlap, like paralysis and speech difficulties, a sudden, severe “thunderclap” headache is more indicative of a burst aneurysm or hemorrhagic stroke.
  • Both conditions require immediate medical attention. While recovery is possible, lasting complications like impaired speech, movement, or cognitive function can occur.

A brain aneurysm is a type of structural problem in a blood vessel in the brain, and a stroke is brain damage that occurs due to an insufficient blood supply to a region of the brain.

An aneurysm often does not cause symptoms unless it bursts or ruptures. Most diagnoses happen during imaging tests for another condition. A doctor will likely monitor the aneurysm and provide medical or surgical treatment to prevent it from worsening or rupturing.

All cases of stroke and ruptured brain aneurysm are medical emergencies, as they can be life threatening. The symptoms can be similar.

They can all lead to paralysis on one side, a loss of balance, difficulty speaking, and headache. However, an aneurysm or hemorrhagic stroke is more likely to produce a “thunderclap” headache, sometimes described as the worst headache a person has ever had.

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Some symptoms are the same for a stroke or an aneurysm, but there are also differences.

Symptoms of a stroke

A stroke is a type of brain damage that occurs due to insufficient blood supply to a region of the brain, usually due to an interruption in blood flow in an artery in the brain.

A person who is having a stroke may experience:

It is important to call for an ambulance if a person has these symptoms.

Symptoms of an aneurysm

Aneurysms that have not burst do not tend to produce symptoms, but a doctor may diagnose an intact aneurysm during a scan for another condition. However, if an aneurysm becomes large, symptoms can start to appear, and there is a higher risk of it bursting.

Around 30 to 50% of people say they had a sudden and severe “thunderclap” headache between 6 and 20 days before a major burst, possibly due to a minor hemorrhage or leak. Doctors call this a sentinel bleed. It is a sign that an aneurysm may burst.

Other signs of an unruptured aneurysm include:

  • vision changes
  • pain above or around the eye
  • numbness or weakness on one side of the face
  • speaking problems
  • headaches
  • loss of balance
  • problems with focusing and thinking

Possible signs of an unruptured brain aneurysm may include:

  • dizziness
  • double vision
  • droopy eyelids

Anyone who has a diagnosed brain aneurysm and develops symptoms should seek medical help as soon as possible. The symptoms may be a warning sign that the aneurysm is going to burst with potentially severe consequences.

The symptoms of a burst aneurysm in the brain can range from mild to severe.

According to the Hunt & Hess scale, grade 1 symptoms include a mild headache and slight neck stiffness. Grade 5 symptoms include a coma and unusual body position known as decerebrate posturing, where the back is arched, and the arms and legs held straight out.

A ruptured aneurysm can also cause:

It is essential to seek medical help if anyone has a sign of a stroke or a burst aneurysm, as both can be life threatening.

There are two main types of stroke: ischemic and hemorrhagic.

An ischemic stroke happens when blood clots, plaque, or other particles block an artery. As a result, the areas of the brain that blood vessel supplies can go through ischemic damage. This occurs due to a starvation of blood, oxygen, and nutrients.

blood can no longer reach all the parts of the brain. This is the most common reason for a stroke.

A hemorrhagic stroke results from a bleed. A blood vessel — or possibly an aneurysm — bursts or leaks, and blood enters parts of the brain where it would not usually be, causing damage. Extremely high blood pressure can trigger a brain hemorrhage if a person has a brain aneurysm.

Around 20% of strokes are hemorrhagic. Hemorrhagic stroke can occur for many reasons, one of which is due to a brain aneurysm.

An intracerebral hemorrhage involves bleeding into the brain tissue. Around half of hemorrhagic strokes are of this type. Intracerebral hemorrhages occur as a result of events such as head trauma, bleeding due to a brain tumor, and hemorrhagic conversion of an ischemic stroke.

Subarachnoid bleeding happens over the surface of the brain. A ruptured brain aneurysm causes subarachnoid bleeding as the blood vessels are present on the surface of the brain and when they rupture, they cause blood to flow into the subarachnoid space. Around 85% of subarachnoid hemorrhages are linked to an aneurysm. Around half of all hemorrhagic strokes are of this type.

An aneurysm is a bulge that results from a weakness in a blood vessel wall. This can increase the risk of further weakening and bleeding. In severe cases, the bulge may burst, leading to significant bleeding in the brain.

Aneurysms vary in shape and size. They can happen anywhere, but the most common locations are the biggest artery leaving the heart, known as the abdominal aorta, and the arteries in the brain.

Why does an aneurysm burst and bleed?

An artery in the brain can burst and bleed because the blood vessel walls become weak. This can lead to a subarachnoid bleed

According to the National Institute of Neurological Disorders and Stroke (NINDS), about 25% of people with a burst brain aneurysm die within the first 24 hours. In another 25%, it will be fatal within 6 months due to complications.

Survival depends on various factors, including age, general health, and how quickly the person receives medical care.

A person with a ruptured brain aneurysm also has a risk of:

  • further bleeding
  • changes to sodium levels in the brain, which can cause brain cells to swell
  • an increase in fluid around the brain, known as hydrocephalus
  • vasospasm or contractions in blood vessels in the brain, which can disrupt blood supply
  • seizures
  • brain swelling, known as cerebral edema

These, in turn, can lead to further problems, including another stroke or permanent brain damage.

What causes a brain aneurysm remains unclear, but some health experts suggests that oxidative stress and inflammation may play a role.

Brain aneurysm

Brain aneurysms can affect anyone, but they appear more likely in people who:

An existing aneurysm is more likely to burst if:

  • it is large or growing in size
  • the person smokes
  • uncontrolled hypertension
  • there is a family or personal medical history of an aneurysm bleeding

Ways of reducing the risk of developing an aneurysm or having one burst include:

Stroke

Here are some factors that increase risk of a stroke:

Steps that can help prevent a stroke include:

  • regular exercise
  • quitting smoking
  • seeking treatment for diabetes, high blood pressure, and other health conditions
  • maintaining a moderate weight

According to the NINDS, it is not always possible to prevent a stroke, but by paying attention to risk factors, 80% of strokes could be avoided.

Treatment options may include:

Hemorrhagic stroke or burst aneurysm

Treatment aims to stop bleeding and prevent further bleeding, but a person may also need treatment to manage or prevent complications. Treatments may also vary due to the underlying cause.

Possible options can include:

  • using the drug nimodipine to reduce the risk of further bleeding
  • surgery to close the aneurysm or prevent blood from pushing into it through either neurosurgical clipping or endovascular coiling
  • drugs to manage blood pressure
  • pain management
  • treatment to manage blood pressure, support breathing, manage electrolytes and glucose, and prevent vasospasm
  • anti seizure medication

An intact brain aneurysm

A doctor may recommend treatment for an intact brain aneurysm if there is a risk of it bursting.

If the aneurysm is small or there is a lower risk of it bursting, the doctor will monitor it. A healthcare professional will weigh the risks of surgery and the risk of rupture. The risks and benefits of surgery are not the same for all individuals.

Clipping or coiling surgery may help prevent a high risk brain aneurysm from rupturing. This procedure repairs the blood vessel by removing the weak outpouching of the blood vessel.

Any type of stroke or a burst brain aneurysm will need emergency treatment, as both can be life threatening. A doctor may also recommend surgery for any aneurysm at risk of rupturing or monitor a low risk aneurysm.

The prognosis for any stroke or a burst aneurysm varies widely, depending on the severity, how soon a person receives treatment, their age, and so on.

The mortality rate for a hemorrhagic stroke due to a ruptured brain aneurysm is around 25% within 24 hours. Around 18% of people who have a hemorrhagic stroke die suddenly before reaching the hospital. In high income countries, around 15% of people do not survive longer than 30 days after an ischemic stroke.

Those who survive may face long term complications, including a risk of recurrence. There may also be brain damage that affects:

  • movement and coordination
  • speech
  • the ability to think and reason

Recovery can take weeks or months, and a person may continue to experience problems. Ongoing rehabilitation can help an individual remain independent and daily functioning, but some people will need long-term full time assistance.

Here are some questions people often ask about strokes and aneurysms.

Are all strokes caused by aneurysms?

No, but 85% of the 50% of hemorrhagic strokes that are subarachnoid hemorrhages are due to brain aneurysms.

Are there warning signs before an aneurysm ruptures?

Often, brain aneurysm does not cause significant symptoms when they are small or before they burst. However, they can cause subtle symptoms before they burst.

They may include dizziness, weakness on one side of the face, a loss of balance, vision changes, and other symptoms.

Around half of those who have a ruptured aneurysm experience a sudden onset headache 6 to 20 days before the rupture occurs.

Are all strokes caused by aneurysms?

A ruptured aneurysm is a common cause of hemorrhagic strokes, where bleeding occurs in or around the brain. However, most strokes are ischemic. Ischemic stroke is brain damage that occurs due to a lack of adequate blood supply to a region of the brain.

Aneurysms and stroke are not the same, but a ruptured aneurysm can lead to a hemorrhagic stroke and bleeding in or around the brain.

Symptoms of an aneurysm that has burst or is likely to burst include a thunderclap headache. This is also a sign of a hemorrhagic stroke. Other common symptoms include weakness or paralysis in one side of the face and difficulty speaking and thinking.

An ischemic stroke results from a blockage rather than bleeding in the brain. Any stroke can be life threatening. With rapid treatment, a person can recover. However, they may continue to experience problems with speech, movement, thinking, and other functions.

For this reason, it is essential to seek emergency medical treatment if anyone appears to be experiencing a stroke or burst aneurysm.