What is a subdural haematoma?

A subdural haematoma is when blood collects between the surface of the brain and the skull. It can be an emergency condition. Most cases occur after a head injury.

Subdural haematomas are classified according to the length of time since the event that caused them:

• Acute subdural haematomas cause symptoms within 2 days of the injury.
• Chronic subdural haematomas may cause symptoms many days or weeks after the injury.

If you have a chronic subdural haematoma, you may have had a mild head injury or no head injury that you can recall. The injury then leads to subtle or slow changes, so symptoms may take longer to develop. Chronic subdural haematomas are more common in older people and are often related to issues with blood clotting.

What are the symptoms of a subdural haematoma?

Symptoms of a subdural haematoma include:

• headache, which is usually severe if you have an acute subdural haematoma
• nausea and vomiting
• drowsiness
• confusion or disorientation
• changes in behaviour
• memory loss
• changes in vision

Your whole body can also be affected by symptoms such as:

• dizziness
• difficulty with balance or walking
• difficulty speaking
• weakness on one side of your body
• numbness or tingling arms or legs

As the size of the subdural haematoma increases, the symptoms can become more severe and include:

• seizures
• loss of consciousness
• coma
• difficulty breathing

What causes a subdural haematoma?

A subdural haematoma is usually caused by a blow to the head, such as may occur in a fall, an assault or a road accident. The blow causes a blood vessel between the surface of the brain and a layer covering the brain to tear. The blood that flows from this blood vessel can't escape the skull, so it gradually puts pressure on the brain, which, if not treated, can lead to paralysis and death.

If you take blood-thinning medicines, you may be at a higher risk of developing a subdural haematoma after a head injury.

How is a subdural haematoma diagnosed?

Your doctor will ask you questions and examine you. If they are concerned about your head injury, you will have brain imaging such as a computed tomography (CT) scan to diagnose any bleeding in or around your brain.

How is a subdural haematoma treated?

The treatment your doctor recommends will depends on the size of haematoma and your symptoms.

If the bleed is very minor and you don't have any symptoms, your doctor may recommend close observation instead of treatment. This involves having regular CT scans to check that the subdural haematoma has resolved over time.

If you have neurological (nerve or brain) symptoms or signs of pressure on your brain, you will usually need emergency surgery to quickly reduce pressure on the brain and remove any blood clots. This is usually followed by treatment with medicines and rehabilitation.

Complications of a subdural haematoma

Left untreated, a subdural haematoma can lead to serious complications including death or long-term disability. Sometimes a subdural haematoma can cause an acquired brain injury (ABI).

Even with surgery, some people experience permanent brain damage and disability.

Resources and support

The NSW Health mild traumatic brain injury factsheet has a helpful guide about monitoring after a visit to the emergency department and when you should seek urgent medical help.

Call Brain Injury Australia on 1800 BRAIN1 (1800 272 461), or download a range of fact sheets about acquired brain injury and how to access support.

Call healthdirect on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.