You might develop signs and symptoms of an intracranial hematoma right after a blow to your head, or they may take weeks or longer to appear. You might seem fine after a head injury, a period called the lucid interval.
However, with time, pressure on your brain increases, producing some or all of the following signs and symptoms:
- Increasing headache
- Drowsiness and progressive loss of consciousness
- Unequal pupil size
- Slurred speech
As more blood fills your brain or the narrow space between your brain and skull, other signs and symptoms may become apparent, such as:
When to see a doctor
An intracranial hematoma can be life-threatening, requiring emergency treatment.
Seek immediate medical attention after a blow to the head if you:
- Lose consciousness
- Have a persistent headache
- Have difficulties such as vomiting, weakness, blurred vision, unsteadiness
If signs and symptoms aren't immediately evident after a blow to the head, watch for physical, mental and emotional changes. For example, if someone seems fine after a blow to the head and can talk but later becomes unconscious, seek immediate medical care.
Also, even if you feel fine, ask someone to keep an eye on you. Memory loss after a blow to your head can make you forget about the blow. Someone you tell might be more likely to recognize the warning signs and get you medical attention.
Head injury, often from motor vehicle or bicycle accidents, falls, assaults, and sports injuries, is the most common cause of intracranial bleeding (hemorrhage).
If you're an older adult — especially if you're taking an anticoagulant or an antiplatelet drug, such as aspirin — even mild head trauma can cause a hematoma.
You can have a serious injury even if there's no open wound, bruise or other obvious damage.
There are three categories of hematoma — subdural hematoma, epidural hematoma and intraparenchymal hematoma.
This occurs when blood vessels — usually veins — rupture between your brain and the outermost of three membrane layers that cover your brain (dura mater). The leaking blood forms a hematoma that presses on the brain tissue. An enlarging hematoma can cause gradual loss of consciousness and possibly death.
The three types of subdural hematomas are:
- Acute. This most dangerous type is generally caused by a severe head injury, and signs and symptoms usually appear immediately.
- Subacute. Signs and symptoms take time to develop, sometimes days or weeks after your injury.
- Chronic. The result of less severe head injuries, this type of hematoma can cause slow bleeding, and symptoms can take weeks and even months to appear. You might not recall injuring your head. For example, bumping your head while getting into the car can cause bleeding, especially if you're on blood-thinning medication.
All three types require medical attention as soon as signs and symptoms appear so that permanent brain damage can be prevented.
The risk of subdural hematoma increases as you age. The risk is also greater for people who:
- Take aspirin or other blood-thinning medication daily
- Abuse alcohol
Also called an extradural hematoma, this type occurs when a blood vessel — usually an artery — ruptures between the outer surface of the dura mater and the skull. Blood then leaks between the dura mater and the skull to form a mass that presses on brain tissue. The most common cause of an epidural hematoma is trauma.
Some people with this type of injury remain conscious, but most become drowsy or go into a coma from the moment of trauma. An epidural hematoma that affects an artery in your brain can be deadly without prompt treatment.
This type of hematoma, also known as intracerebral hematoma, occurs when blood pools in the brain. There are many causes, including trauma, rupture of an aneurysm, vascular malformation, high blood pressure and tumor. There are also diseases that can cause spontaneous leakage of blood into the brain. A head trauma can result in multiple severe intraparenchymal hematomas.