What is a subdural haematoma and what causes it?
A subdural haematoma is a collection of clotting blood that forms in the subdural space. It usually occurs because of an injury to the head. For example, someone falling and hitting their head, or being involved in an accident that causes a head injury. The head injury can damage and cause bleeding from one or more blood vessels near to or within the subdural space. The blood from the bleeding blood vessel(s) collects in the subdural space. The head injury may also cause injury to the brain tissue at the same time. Sometimes a subdural haematoma can be due to spontaneous bleeding. That is, there is no injury that causes the bleeding. This can happen if you have a problem with the clotting of your blood. For example, if you take medication to ‘thin the blood’ (anticoagulation) or if your blood is thinner for another reason (such as with haemophilia or thrombocytopenia). Another rare cause of a subdural haematoma is bleeding from an abnormal blood vessel within the brain called an aneury
