A hematoma is a collection of blood outside the blood vessels. This generally occurs when a blood vessel ruptures, allowing the blood to escape and pool in a certain area. We commonly refer to them as bruises, but bruising in and around the brain can be life threatening. There are three types of hematoma that can occur in the brain, each with varying levels of severity.
Epidural/extradural hematomas occur when blood accumulates between the skull and the dura (the thick membrane that covers the outer layer of the brain). In about 90% of victims, a fractured skull from a localized and direct blow to the head causes the injury. Parts of the skull splinter and chip off into the brain, cutting the blood vessels.
Due to the location of the hematoma, on the outer bounds of the brain, injury victims usually recover well with proper treatment. Mortality rates are extremely low and serious brain damage is unlikely. More severe cases, hematomas larger than 1 cm in diameter, may need surgery to reduce the buildup of blood in the brain, but they generally can be treated with medication.
Intracranial hematomas occur when a blood vessel ruptures between your skull and brain or inside your brain. The blood pools and increases pressure on the brain tissue. Too much pressure on the brain can cut off blood supply to brain cells and crush brain tissue causing irreversible consequences. This type of hematoma is potentially fatal and demands immediate treatment, usually surgery to drain the blood and release the pressure on the brain.
These can occur after sudden acceleration or deceleration or a sudden blow to the head. The brain is surrounded in fluid to keep it safe from the bony skull. In the event of a quick stop or something striking the head, the brain moves and forces the fluid out of the way, allowing the brain to hit the skull. This usually causes hematoma.
Subdural hematomas are the most lethal of the cerebral hematomas. They occur when blood collects outside the brain, between the dura (outermost membrane surrounding the brain) and the arachnoid (layer just inside the dura). As with the other hematomas, increased pressure on the brain from the blood pools can stop blood flow to the brain and cause cell damage. If the blood accumulates quickly, causing increasing pressure the hematoma can lead to unconsciousness, coma or death.
Subdural hematomas can be caused by both minor and serious head injuries. In the event of minor head trauma, the bleeding pools slowly, sometimes going unnoticed for weeks. We call these chronic subdural hematomas. People that take anticoagulants medications and have conditions affecting ability to clot are at higher risk for chronic subdural hematomas.
When the blood pools between the dura and arachnoid very rapidly after a serious head trauma, it is called an acute subdural hematoma. These are particularly dangerous because they require immediate treatment to prevent brain damage and death. Surgery is always required to remove the blood and release pressure on the brain.
The varying degrees of cerebral hematoma can be detected by your doctor with the help of a CT scan or MRI test. This will allow them to identify the location of the problem and determine the best way to treat your hematoma.