Subdural haematoma - Diagnosing subdural haematoma

Subdural haematomas are diagnosed based on a person’s medical history, symptoms and the results of an imaging scan of the brain.

Acute subdural haematomas

Due to the nature of the condition, most cases of acute subdural haematomas are diagnosed in an accident and emergency (A&E) department.

After a head injury, healthcare professionals use the Glasgow Coma Scale (GCS) to assess how severely your brain has been damaged. The GCS scores you on:

your verbal responses (whether you can speak appropriately or make any sounds at all)
your physical response (whether you can move voluntarily or in response to stimulation)
how easily you can open your eyes

A slightly different version of the GCS is used for children under five years old.

If you achieve a score of 15 (the highest possible score) it indicates that you know who and where you are, that you can speak and move as instructed, and that your eyes are open.

A score of 3 (the lowest possible score) means that you cannot open your eyes and you cannot move or make a noise. This score indicates that your body is in a deep coma.

Depending on your score, head injuries are classed as:

minor – a GCS score of 14 to 15
moderate – a GCS score of 9 to 13
severe – a GCS score of 3 to 8

A GCS score of 8 or below is commonly seen in people with an acute subdural haematoma. As a precaution, anyone with a GCS score below 15 should be given a CT scan within one hour of the request being made by A&E staff.

If you have an acute subdural haematoma, it usually shows up on a CT scan as a white semi-circular mass, just under the surface of your skull.

Chronic subdural haematoma

Diagnosing cases of chronic subdural haematoma can be more difficult for two reasons:

many of the symptoms of a chronic subdural haematoma are shared by other health conditions, such as dementia, Parkinson’s disease or brain tumour
many people cannot recall sustaining a head injury that could be associated with the onset of symptoms

It may therefore take several days or weeks before the correct diagnosis is confirmed and you may be referred for a series of tests designed to rule out other possible causes of your symptoms.

Most cases of chronic subdural haematoma can be diagnosed using a CT scan because the haematoma will often show up as a mass that is of a different density to the brain. However, in some cases, the blood clot can take on a similar density, which makes it harder to detect.

If this is the case, you may have an MRI scan.