Subdural hematoma. Epidural hematoma.
Subdural hematoma is accumulation of blood between dura and arachnoid matter. Subdural space is anatomically present which determines the larger area and volume of this type of hematoma (300-400cm3). Usually, the source of bleeding is either a torn bridging vein (passing from the brain surface to a dural sinus) or a torn cortical artery in a zone of cerebral contusion. According to the period of formation and time of diagnosis subdural hematomas can be:
- Acute – within first three days;
- Subacute – from 4th to 20th day;
- Chronic – after 21st day- there is capsule formation.
Classification
Acute subdural hematomas that are due to trauma are the most lethal of all head injuries and have a high mortality rate if they are not rapidly treated with surgical decompression.
Acute bleeds often develop after high speed acceleration or deceleration injuries and are increasingly severe with larger hematomas. They are most severe if associated with cerebral contusions. Though much faster than chronic subdural bleeds, acute subdural bleeding is usually venous and therefore slower than the typically arterial bleeding of an epidural hemorrhage.
Chronic subdural bleeds develop over a period of days to weeks, often after minor head trauma though such a cause is not identifiable in 50% patients. They may not be discovered until they present clinically months or years after a head injury. The bleeding from a chronic bleed is slow, probably from repeated minor bleeds, and usually stops by itself.
Clinical presentation of acute subdural hematoma
- Commonly combines with cerebral contusion
- There is progression of headache, deterioration of consciousness and focal neurological deficit depending on the localization.
Clinical presentation of chronic subdural hematoma
- Patient has sustained head injury which he/she does not remember
- Mild to moderate headache
- Mild neurological deficit.
Subdural hematomas are often life-threatening when acute. Chronic subdural hematomas, however, have a better prognosis if properly managed.
Symptoms
Symptoms of subdural hematoma depend mostly on the rate of bleeding:
- In head injuries with sudden, severe bleeding causing a subdural hematoma, person may lose consciousness.
- A person may appear normal for days after a head injury, but slowly become confused and then unconscious several days later. This results from a slower rate of bleeding, causing a slowly enlarging subdural hematoma.
- In very slow-growing subdural hematomas, there may be no noticeable symptoms for more than two weeks after the bleeding starts.
Diagnosis
- CT/MRI