Both conditions result from problems in the blood vessel walls.
Some of the risk factors and the symptoms are the same, but there are key differences.
Symptoms of a stroke
A brain aneurysm is different from a stroke, but it can lead to a stroke. It is important to know the signs of both conditions.
Most strokes happen because of a blocked artery.
A person who is having a stroke may experience:
- drooping on one side of the face
- an inability to lift the arms
- weakness or numbness in one arm
- slurred speech or inability to talk
- complete paralysis of the body along one side
- sudden vision disturbance
- confusion or difficulty understanding other people
- loss of balance or coordination
- difficulty swallowing
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.
Symptoms are likely to appear only if the size of the bulge is large. Then the aneurysm has a high risk of bursting.
Anyone with a diagnosis of a brain aneurysm who develops symptoms should seek medical help as soon as possible, as treatment may prevent a burst.
An intact brain aneurysm may produce symptoms such as:
- vision problems, such as double vision
- pain above or around the eye
- an enlarged pupil in the eye
- weakness or numbness of the face
- loss of balance
- speaking difficulties
- problems with thinking
A burst aneurysm in the brain usually causes:
- an extreme "thunderclap" headache
- stiff neck
- sensitivity to light
- collapse, seizure, or coma
A sentinel bleed is a small bleed that happens when a person has an aneurysm. This can be a sign that an aneurysm is going to burst. Symptoms include headaches.
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.
Aneurysm versus stroke symptoms
If an aneurysm has not burst, there are not usually any symptoms.
A sudden headache is the main difference between a burst aneurysm and a stroke that results from a blood clot.
Within seconds of a brain aneurysm bursting, there is usually a severe headache.
Other signs and symptoms may differ between a burst aneurysm and common stroke. Sudden extreme headache is the one that is noticeably different, however.
What is a stroke?
A stroke is a medical emergency. Blood supply to parts of the brain suddenly stops, starving these parts of oxygen and nutrients. This can cause the death of brain tissue.
A stroke can be ischemic or hemorrhagic.
Ischemic stroke: An artery is blocked, and blood supply no longer reaches all the parts of the brain.
Hemorrhagic stroke: A blood vessel bursts or leaks, and blood enters parts of the brain where it would not normally be.
The two types of hemorrhagic stroke are:
Intracerebral: Bleeding occurs within the brain.
Subarachnoid: Bleeding happens over the surface of the brain, and blood enters the fluid-filled space between the brain and the underside of the skull bone. It is uncommon. A physical effort or straining can trigger it.
Most strokes are ischemic.
What is an aneurysm?
An aneurysm is a bulge in an artery. It bulges because of a weakness in an artery wall. This makes the artery open to further weakening, and it could burst.
Aneurysms vary in shape, size, and location.
Aneurysms can affect any blood vessel. The most important aneurysms affect the biggest artery leaving the heart and the arteries in the brain.
Why does an artery burst and bleed?
A thunderclap headache is a classic sign of a burst aneurysm.
An artery in the brain may burst and bleed because the walls of the blood vessel become weak.
This can be due to a subarachnoid hemorrhage type of stroke, as mentioned above, or because of an aneurysm.
A person who has an aneurysm has a higher risk of a stroke or bleeding in the brain. A person with a burst aneurysm needs immediate medical attention.
Burst aneurysms are dangerous
When a brain aneurysm bursts, it is a medical emergency that needs urgent treatment. Without immediate help, a burst aneurysm can be fatal.
The National Institute of Neurological Disorders and Stroke (NINDS) say that about 25 percent of people who have a burst brain aneurysm die within the first 24 hours. In 25 percent of cases, it will be fatal 6 months due to complications.
Survival depends on a number of factors, including age, general health, and how quickly the person receives medical care.
With treatment, a person may survive a burst brain aneurysm, but complications can remain.
- a higher chance of another burst aneurysm
- long-term brain damage
- problems relating to the nervous system
Risk factors and prevention
Factors that increase the risk of a stroke or an aneurysm include:
- high blood pressure
- older age
Smoking is dangerous for anyone who has an intact aneurysm, since it raises the risk of it bursting.
Stroke risk factors and prevention
A number of risk factors raise the risk of a stroke. The biggest preventable risk factors are:
- smoking or other tobacco use
- lack of physical activity
- poor diet
There are also genetic factors, such as a family history of heart disease or stroke. A person cannot prevent these.
Factors that are partly avoidable or manageable include:
Aneurysm risk factors and prevention
Major risk factors that increase the chances of a brain aneurysm are:
- high blood pressure
- the use of certain substances, such as cocaine and amphetamines
- excessive alcohol consumption
These also raise the risk of an aneurysm bursting.
Having both risk factors together adds to the risk by a greater amount than simply adding together the two individual factors.
Other risk factors that are not preventable are:
- family history and other genetic factors
- hormonal factors
- being aged between 40 and 65 years
A person may have a higher risk if they have one or more of the following health conditions:
- polycystic kidney disease
- arteriovenous malformations, or tangles of blood vessels in the brain
- a head trauma
- a brain tumor
- infection in the arterial wall of the brain
Genetic risk can interact with other factors for aneurysm. Smoking, for example, can be more risky for some people than for others.
One way to prevent an aneurysm forming is to take regular exercise. This also has wider health benefits.
A study published in 2013 found that factors that may help reduce the risk of an aneurysm bursting include:
- quitting or avoiding smoking
- maintaining healthy cholesterol levels
- maintaining a healthy blood pressure
The treatment options for stroke and aneurysm are different.
Rehabilitation after a stroke can help a person to recover from the effects.
The treatment of a stroke depends on the type of stroke. However, a subarachnoid hemorrhage or hemorrhagic stroke has the same treatment as a stroke caused by a burst brain aneurysm.
Treatment depends on the type.
Treatment for an ischemic stroke includes:
- drugs to dissolve clots and others to prevent further clotting
- blood thinners, such as warfarin
- drugs to lower blood pressure
- statins to reduce cholesterol levels
The person may have surgery if there is severe narrowing of the main supply vessel to the brain
Survivors of a stroke may also undergo a program of stroke rehabilitation.
Treatment for a subarachnoid hemorrhage after a burst brain aneurysm is covered below.
Burst brain aneurysms or hemorrhagic stroke
If there is a hemorrhage or a brain aneurysm has burst, the doctor will usually refer a person to a specialist neurology center.
Treatment may include:
- immediate drug treatment with nimodipine
- surgery can close the aneurysm or prevent blood from pushing into it
Two different types of surgery are available:
- neurosurgical clipping
- endovascular coiling
Clipping involves the surgeon finding the aneurysm in the brain and applying a small metal clip. The clip is usually placed directly across the bulging part of the artery.
For coiling, the brain is reached with a catheter rather than through an opening in the skull. This is inserted at the groin or leg and travels up to the brain in an artery. Coils made of platinum are placed in the aneurysm to prevent blood from entering.
This reduces the risk of losing blood supply to any part of the brain and improves the chances of a better outcome.
Intact brain aneurysms
A brain aneurysm that has not yet burst can be treated 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. The risks of surgery are not worth taking with a low-risk aneurysm.
Clipping or coiling surgery may help prevent a high-risk brain aneurysm from rupturing. It can stop blood from flowing into the aneurysm.
Both a stroke and a burst aneurysm need emergency treatment, as both can be life-threatening.
If a person survives a stroke or a burst aneurysm, they may have complications such as difficulty with speaking, thinking, and coordination.
It is important to monitor an existing aneurysm to prevent it from bursting, and to take measures, such as avoiding or quitting smoking, to reduce the risk of a stroke or an aneurysm.
Following a varied and healthful diet, maintaining a healthy weight, and getting enough exercise can also reduce the risk of many health problems, including an aneurysm or stroke.