Subdural haematoma

A subdural haematoma is a serious brain condition that is often caused by a head injury. Blood collects between the skull and the surface of the brain.

Symptoms of a subdural haematoma can include:

  • vomiting
  • mental confusion
  • coma

Symptoms can appear quickly or may develop over time depending on the type of subdural haematoma (see below).

Read more about the symptoms of a subdural haematoma.

A subdural haematoma occurs when a blood vessel in the space between the skull and the brain (the subdural space) is ruptured. Blood escapes from the ruptured blood vessel, leading to the formation of a blood clot (haematoma), which places pressure on the brain and may cause brain damage.

Read more about the causes of a subdural haematoma.

Types of subdural haematoma

A subdural haematoma can be:

  • acute – the haematoma forms immediately after the initial injury
  • subacute - the haematoma forms up to a week after the initial injury
  • chronic – the haematoma forms over a period of two to three weeks after the initial injury

These are discussed in more detail below.

Acute subdural haematoma

Acute subdural haematomas are the most serious type of subdural haematoma. They usually occur after severe, high-impact head injuries, often caused by motor vehicle accidents, falls and physical assaults.

An acute subdural haematoma is a medical emergency that requires immediate admission to a hospital. Surgery is usually required to remove the haematoma.

Subacute subdural haematoma

Subacute subdural haematomas are less common, and often harder to detect, than other types of subdural haematoma.

The signs and symptoms can appear days, or even weeks, after an injury and will be similar to those of an acute subdural haematoma.

Chronic subdural haematoma

Chronic subdural haematomas are more commonly seen in older people. It is thought they occur because the natural ageing process makes the brain more vulnerable to injury in some people.

This means that even a minor injury can cause bleeding inside the subdural space (in around half of all cases, the injury is so minor that the person cannot remember it).

The symptoms of a chronic subdural haematoma often develop several weeks after the initial injury, because our brain usually shrinks as we get older, creating more subdural space for the haematoma to expand into before it causes any noticeable symptoms.

Chronic subdural haematomas may also be regarded as a medical emergency. Surgery is usually required.

Read more about how a subdural haematoma is treated.


Acute subdural haematoma carries a high risk of death. Age is an important factor that affects a person’s outlook. For example, people who are:

  • under 40 years old have a 20% risk of dying
  • 40 to 80 years old have a 65% risk of dying
  • 80 years old or over have an 88% risk of dying

People who survive an acute subdural haematoma usually take a long time to recover from the effects of the haematoma. The recovery time will depend on the severity of the haematoma. There can also sometimes be permanent physical and mental disabilities.

Read more about recovering from a subdural haematoma.

Less information is available about subacute subdural haematomas as they are less common. However, the outlook for a subacute subdural haematoma is often better than for an acute subdural haematoma.

The outlook for a chronic subdural haematoma is also much better than the outlook for acute subdural haematoma. However, the condition still carries a moderately high risk of death. An estimated 1 in 20 people will die within the first 30 days after having surgery to treat a chronic subdural haematoma.

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