If you develop symptoms associated with a subarachnoid haemorrhage, such as a sudden severe headache, you will be admitted to hospital for further testing.
(Due to the potential serious nature of a subarachnoid haemorrhage treatment may be given as a precaution even if the diagnosis is still unconfirmed).
There are four main tests used to confirm (or disprove) a diagnosis of a subarachnoid haemorrhage. These are outlined below.
Computerised tomography (CT) scan
A computerised tomography (CT) scan is like an X-ray, but it uses multiple scans or images to build up a more detailed three-dimensional picture of your brain. The scan can be used to detect the presence and location of blood around your brain and any problems that it may be causing. Sometimes a coloured dye is injected into the blood to help pinpoint the source of the bleeding.
Read more about CT scans.
Lumbar puncture
The brain and spinal column are surrounded by a clear liquid called cerebrospinal fluid. If a subarachnoid haemorrhage has occurred, there will be blood in the fluid. To get a sample of cerebrospinal fluid, a needle is inserted into the lower end of your spine and a sample is drawn off. You may find the procedure a little uncomfortable but you will be given a local anaesthetic to numb the area.
Read more about lumbar punctures.
MRI scan
A magnetic resonance imaging (MRI) scan uses strong magnetic fields and radio waves to produce a detailed image of the inside of the body. The scan can be used to detect problems in the blood vessels and, occasionally, detect the haemorrhage itself.
Read more about MRI scans.
Doppler ultrasound
One of the most serious complications associated with subarachnoid haemorrhage is poor blood supply to the brain, called secondary cerebral ischaemia. This may in part be due to arteries in the brain going into spasm (vasospasm), leading to further loss of blood, brain damage and possibly death. Often, vasospasm causes no immediate symptoms so the condition can go unnoticed.
A Doppler ultrasound is a test that uses ultrasound to monitor the flow of blood in the arteries. Sudden changes in the speed of blood flow would indicate that a cerebral vasospasm has occurred, so immediate treatment would then begin.
Read more ultrasound scans.
