Subdural hematoma (blood in the subdural space) is a frequent complication of head injuries. To localize and understand this issue, it is necessary to say a few words about the anatomy of the brain and intracranial space.
The brain is covered with 3 layers. Closest to the brain is the pia mater, the middle layer is called arachnoid mater and the layer farthest from the brain is known s the dura mater. Dura mater is in close contact with the skull bones. The term subdural hematoma can be translated as presence of blood under the dura mater, i.e. between the dura and arachnoid mater.
The subdural hematoma has some very important differences from the epidural hematoma. Aside from slightly different localization, the subdural hematoma comes from the intracranial veins and represents venous bleeding. Due to local anatomical arrangement, the bleeding starts after blows to the head from the front or back direction. Venous bleeding is usually less severe than arterial and it has a greater tendency to stop by itself.
Acute subdural hematoma
This situation occurs when the bleeding is strong and the hematoma is growing fast. The patient may suffer from signs of intracranial hypertension such as headache, nausea and vomiting. The risk of sudden death is significant.
Chronic subdural hematoma
The bleeding usually proceeds very slowly or it stops. The hematoma gradually increases and slightly oppresses the brain or it even dose not grow anymore and stabilizes. However, even the stabilized subdural hematoma may rebleed after some time and symptoms of an acute subdural hematoma may occur weeks or months after the injury. Classic symptoms of a chronic subdural hematoma include recurring headaches, personality changes, fatigue and dementia. Dementia in a subdural hematoma can be sometimes mistakenly confused with incipient Alzheimer's disease. If the brain oppression slowly continues, it can begin to manifest with muscle paralysis and sensitivity disorders in various body parts and this can ultimately lead to death.
The best diagnostic method is the computed tomography of the brain, which is an ideal examination in people with recent history of a head injury. The hemorrhage has a half-moon shape located between the dura mater and arachnoid mater. Large hematomas may push the brain tissue to other side of the skull. Magnetic resonance imaging is also fully potent to confirm the hematoma, but it is a less accessible method.
The prevention is to avoid blows to the head and seek medical assistance after any major head injury.
Small subdural hematomas may be only monitored, but large ones with clinical symptoms should be treated. The primary method of treatment is neurosurgical intervention, when the patient’s skull is opened, the bleeding stopped and the blood and blood clots drained.