What is subdural hematoma?
A subdural hematoma is a type of bleed inside your head. More precisely, it is a type of bleed that occurs within the skull of head but outside the actual brain tissue. The brain has three membranes layers or coverings (called meninges) that lay between the bony skull and the actual brain tissue. The purpose of the meninges is to cover and protect the brain.
If you have a subdural hematoma, you have experienced a tear in a blood vessel, most commonly a vein, and blood is leaking out of the torn vessel into the space below the dura mater membrane layer. This space is called the subdural space because it is below the dura. Bleeding into this space is called a subdural hemorrhage.
Other names for subdural hematoma are subdural hemorrhage or intracranial hematoma. More broadly, it is also a type of traumatic brain injury (TBI).
How common are subdural hematomas?
Subdural hematomas occur in up to 25% of people with head injuries.
Are subdural hematomas serious?
Yes, a subdural hematoma can be a serious event. Occasionally, the bleed is slow and the body is able to absorb the pooled blood. However, if the hematoma is severe, the buildup of blood can cause pressure on the brain. This pressure can lead to breathing problems, paralysis and death if not treated.
Because you don’t immediately know how severe a brain bleed is until further testing, all blows to the head should be considered a serious event. If you hit your head, get checked out at a hospital.
Are there different types of subdural hematomas?
Yes. Doctors sort subdural hematomas by how fast they develop, how much bleeding occurs, and how much damage the bleeding causes. The types of subdural hematoma are:
- Acute: This is the most dangerous type of subdural hematoma. Symptoms are severe and appear right after a head injury, often within minutes to hours. Pressure on the brain increases quickly as the blood pools. If not diagnosed and treated quickly, you could lose consciousness, become paralyzed or even die.
- Subacute: Symptoms usually appear hours to days or even weeks after the head injury. A subacute subdural hematoma can occur with a concussion.
- Chronic: This type of hematoma is more common in older people. Bleeding occurs slowly and symptoms may not appear for weeks or months. Even minor head injuries can cause chronic subdural hematomas. Due to the delay in developing symptoms, an older person may not even recall how their head injury happened. Also, the changes can be so subtle and occur so slowly that symptoms may not be noticed by the older person or their friends or family.
Are some people more likely to get a subdural hematoma?
Although anyone can get a subdural hematoma from an accidental head injury, certain groups of people are at higher risk. Subdural hematomas are more common in:
- Older adults: As we age, our brains shrinks within our skull and the space between the skull and brain widens. This causes the tiny veins in the membranes between the skull and the brain to stretch. These thinned, stretched veins are more likely to tear in the event of even a minor head injury, such as a fall out of a chair.
- Athletes who play contact sports: Football players and others who play high-impact sports and who might take a blow to the head have an increased risk of a hematoma.
- People who take blood thinners: Blood thinners slow down the clotting process or prevent blood from clotting at all. If blood doesn’t clot, bleeding can be severe and long-lasting, even after a relatively minor injury.
- Hemophiliacs: Hemophilia is an inherited bleeding disorder that prevents blood from clotting. People with hemophilia have a higher risk of uncontrolled bleeding after an injury.
- Alcoholics and people who abuse alcohol: Drinking too much alcohol causes liver damage over time. Damaged livers can’t produce enough of the proteins that help the blood to clot, which increases the risk of uncontrolled bleeding.
- Babies: Babies don’t have strong neck muscles to protect themselves from trauma to the head. When someone abuses a baby by shaking him or her, the baby can develop a subdural hematoma. This type of injury is called shaken baby syndrome.
How do subdural hematomas happen?
Head injuries cause most subdural hematomas. If you fall and hit your head or take a blow to the head in a car or bike accident, a sporting activity or have another type of head trauma, you are at risk for developing a subdural hematoma.
What are the symptoms of subdural hematoma?
Because a subdural hematoma is a type of traumatic brain injury (TBI), they share many symptoms. Symptoms of a subdural hematoma may appear immediately following trauma to the head, or they may develop over time – even weeks to months.
Signs and symptoms of a subdural hematoma include:
- Headache that doesn’t go away. (Headache is usually severe in the case of acute subdural hematoma.)
- Confusion and drowsiness.
- Nausea and vomiting.
- Slurred speech and changes in vision.
- Dizziness, loss of balance, difficulty walking.
- Weakness on one side of the body.
- Memory loss, disorientation, and personality changes, especially in older adults with chronic subdural hematoma.
- Enlarged head in babies, whose soft skulls can enlarge as blood collects.
As bleeding continues and the pressure in the brain increases, symptoms can get worse. Symptoms, at this point, include:
- Breathing problems.
- Loss of consciousness and coma.
Sometimes people have no symptoms immediately following a head injury. This is called a lucid interval. They develop symptoms days later. Also, it’s important to know that subdural hematomas that develop more slowly (the chronic type) might be mistaken for other conditions, such as a brain tumor or stroke.
Special note about head injury and symptoms in seniors: Some of the symptoms of subdural hematoma in older people, like memory loss, confusion, and personality changes, could be mistaken for dementia. The older person may not remember hitting their head. Sometimes, people forget because they are disoriented. Other times, the injury was minor and may have occurred weeks before symptoms appeared. They should still see their healthcare provider for evaluation.