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Stroke health centre

Bleeding in the brain

What is bleeding in the brain?

A brain haemorrhage, also known as subarachnoid haemorrhage, is bleeding in the brain.

Subarachnoid haemorrhage is a type of stroke, accounting for around 1 in 20 of all strokes.

A subarachnoid haemorrhage is caused by an artery in the brain bursting and causing bleeding in the surrounding tissues, that kills brain cells.

The most common symptom reported for a subarachnoid haemorrhage is a severe headache that comes on suddenly.

What happens during a brain haemorrhage?

When blood from a trauma irritates brain tissues, it causes swelling. This is known as cerebral oedema. The pooled blood collects into a mass called a haematoma. These conditions increase pressure on nearby brain tissue, and that reduces vital blood flow and kills brain cells.

Bleeding can occur inside the brain, between the brain and the membranes that cover it, between the layers of the brain’s covering, or between the skull and the covering of the brain.


What causes bleeding in the brain?

There are several risk factors and causes of brain haemorrhages. The most common include:

  • Head trauma. Injury is the most common cause of bleeding in the brain for those under 50.
  • High blood pressure. This long-term condition can, over a long period of time, weaken blood vessel walls. Untreated high blood pressure is a major preventable cause of brain haemorrhages.
  • Aneurysm. This is a weakening in a blood vessel wall that swells. It can burst and bleed into the brain, leading to a stroke.
  • Blood vessel abnormalities. Weaknesses in the blood vessels in and around the brain may be present at birth and diagnosed only if symptoms develop.
  • Amyloid angiopathy. This is an abnormality of the blood vessel walls that sometimes occurs with ageing. It may cause many small, unnoticed bleeds before causing a large one.
  • Blood or bleeding disorders. Haemophilia and sickle cell anaemia can both contribute to decreased levels of blood platelets.
  • Liver disease. This condition is associated with an increased risk of bleeding in general.
  • Brain tumours.

What are the symptoms of brain bleeding?

The symptoms of a brain haemorrhage can vary. They depend on the location of the bleeding, the severity of the bleeding, and the amount of tissue affected. Symptoms may develop suddenly or over time. They may progressively worsen or suddenly appear.

If you exhibit any of the following symptoms, you may have a brain haemorrhage. This is a life-threatening condition, and you should call 999 or go to the accident and emergency department of your local hospital immediately. The symptoms include:

  • A sudden severe headache
  • Seizures with no previous history of seizures
  • Weakness in an arm or leg
  • Nausea or vomiting
  • Decreased alertness, lethargy
  • Changes in vision
  • Tingling or numbness
  • Difficulty speaking or understanding speech
  • Difficulty swallowing
  • Difficulty writing or reading
  • Loss of fine motor skills
  • Loss of coordination
  • Loss of balance
  • An abnormal sense of taste
  • Loss of consciousness

Bear in mind that many of these symptoms are often caused by conditions other than brain haemorrhages.

WebMD Medical Reference

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