Brain Aneurysm

A brain aneurysm, also called a cerebral or intracranial aneurysm, is a swelling or bulge in a blood vessel in the brain. It develops where the wall of an artery has become weak, allowing it to balloon outwards as blood flows through. Aneurysms vary in size and most often form where blood vessels branch.

It is important to separate two situations. An unruptured aneurysm has not burst and frequently causes no symptoms at all. A ruptured aneurysm has burst and is bleeding, which is a serious, life-threatening emergency that needs immediate hospital treatment.

Most unruptured brain aneurysms produce no symptoms and are only discovered during tests done for another reason. A larger unruptured aneurysm that presses on nearby tissue can sometimes cause pain above or around one eye, a drooping eyelid, blurred or double vision, numbness on one side of the face, or a dilated pupil.

A ruptured aneurysm typically causes a sudden, extremely severe headache, often described as the worst headache of a person's life and unlike any felt before. Other signs include a stiff neck, sensitivity to light, nausea and vomiting, blurred or double vision, sudden confusion, weakness, seizures, or loss of consciousness.

Call emergency services immediately if you or someone else has a sudden, agonising headache that comes on like a thunderclap, particularly if it is accompanied by a stiff neck, vomiting, sensitivity to light, slurred speech, weakness, a drooping face, seizures or loss of consciousness. These can be signs that an aneurysm has ruptured.

A ruptured brain aneurysm is a medical emergency. Acting fast and getting to hospital quickly can be the difference between life and death and can affect how well a person recovers. Do not wait to see if the headache passes.

Aneurysms form in areas where the artery wall is weaker, but the exact reason one develops is not always known. Several factors raise the risk, including smoking, high blood pressure, increasing age, and a family history of brain aneurysms. Heavy alcohol use and the use of certain drugs such as cocaine also increase risk.

Some inherited conditions, such as polycystic kidney disease and certain connective tissue disorders, are linked to a higher chance of brain aneurysms. Having one of these risk factors does not mean an aneurysm will definitely form or burst, but reducing the factors you can control is helpful.

If a rupture is suspected, doctors usually arrange an urgent CT scan of the head to look for bleeding around the brain. If the scan does not show bleeding but suspicion remains, a lumbar puncture may be done to check the fluid around the brain and spinal cord for signs of blood.

To see the blood vessels in detail and locate an aneurysm, imaging such as CT angiography, MRI angiography, or a catheter cerebral angiogram may be used. These tests show the size, shape and position of the aneurysm, which helps the team decide whether and how to treat it.

A ruptured aneurysm needs emergency treatment to stop the bleeding and prevent it bleeding again. Two main procedures are used. In endovascular coiling, a thin tube is guided through the blood vessels to pack the aneurysm with tiny coils, sealing it off from the inside. In surgical clipping, a small metal clip is placed across the base of the aneurysm during an operation.

For an unruptured aneurysm, treatment is not always needed. The team weighs the risk of it bursting against the risks of treatment, taking into account the aneurysm's size, shape and location, as well as the person's age and health. Some aneurysms are simply monitored with regular scans, while others are treated to prevent a future rupture.

You cannot guarantee an aneurysm will not form, but you can lower your risk by not smoking, keeping blood pressure within a healthy range, eating a balanced diet, staying active, and avoiding heavy alcohol use and recreational drugs. People with a strong family history may be offered screening in some cases.

The outlook depends greatly on whether the aneurysm has ruptured. Many small unruptured aneurysms never cause problems. A ruptured aneurysm is serious and can be fatal or cause lasting effects, but prompt emergency treatment and specialist rehabilitation improve the chances of recovery. Recovery time varies from person to person.