Subdural haemorrhage is the flow of blood from the blood vessels in dura – the outer envelope (meninges) of the brain. It differs from extradural haemorrhage because the ruptured blood vessels are located on the lower, not from upper side of dura. Since these internal vessels are smaller than external vessels, blood leakage will probably be weaker; the blood is usually leaking slowly into the space between dura and arachnoid (middle cerebral cortex). Therefore, it will often take a long time – up to several weeks – before the ever-increasing pressure on the brain tissue under the dura starts to trigger noticeable symptoms.
Symptoms that may eventually appear in subdural bleeding include drowsiness, confusion, vision disorders, weakness or numbness on one side of the body, and persistent or frequent headaches and nausea. Such symptoms may appear and disappear during several days or weeks, but will gradually get even worse.
Subdural haemorrhage is very rarely one of the complications in head injury. It most commony happens if older people fall, and sometimes they forget this accident when the symptoms appear.
What to do?
If you notice any of the symptoms described, contact your doctor immediately. Since the symptoms are similar to symptoms of a mild stroke, do not forget to tell your doctor if you have recently suffered head injuries (even if this injury was insignificant). Your doctor will probably send you to the hospital for diagnostic tests, i.e. X-rays, arteriography, radioisotope recording, and probably brain scan (so-called computerized axial tomography) to determine the cause of your symptoms. If the tests confirm the diagnosis of subdural haemorrhage, treatment is similar to that of extradural haemorrhage.