Subdural Hematoma

What is a subdural hematoma?

A subdural hematoma is a type of bleeding inside your head. It happens when blood collects under the dura mater, one of the layers of tissue that protect your brain. It most often happens from a head injury and can be fatal.

The dura mater is one of the meninges — the three layers of membranes that cover and protect your brain and spinal cord. They include:

• Dura mater: This is the outer layer, closest to your skull.
• Arachnoid mater: This is the middle layer.
• Pia mater: This is the inner layer, closest to your brain tissue.

A subdural hematoma develops from a tear in a blood vessel. Blood leaks out of the torn vessel into the space between your dura mater and your arachnoid mater. Active bleeding into this space is called a subdural hemorrhage. A buildup of blood is a subdural hematoma.

More broadly, a subdural hematoma is a type of traumatic brain injury (TBI).

Subdural hematomas can be life-threatening and need immediate medical care.

Types of subdural hematomas

Healthcare providers sort subdural hematomas by:

• How fast they develop.
• How much bleeding occurs.
• How much damage the bleeding causes.

The types of subdural hematomas include:

• Acute: This is the most dangerous type of subdural hematoma. The symptoms are severe and appear right after a head injury, often within minutes to hours. Pressure on your brain increases quickly as the blood pools. If you’re not diagnosed and treated quickly, you could lose consciousness, have paralysis 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 people older than 65. Bleeding occurs slowly and symptoms may not appear for weeks or months. Even minor head injuries can cause chronic subdural hematomas. You may not even recall how your head injury happened due to the delay in developing symptoms.

How common are subdural hematomas?

Subdural hematomas happen in around 1 in 4 people with head injuries.

What are the symptoms of subdural hematomas?

Symptoms of a subdural hematoma may appear immediately following trauma to your head. Or they may develop over time — even weeks to months after the injury.

Signs and symptoms of a subdural hematoma include:

• A headache that doesn’t go away. It’s usually severe in acute subdural hematomas.
• Nausea and vomiting.
• Slurred speech (dysarthria).
• Changes in your vision.
• Dizziness.
• Balance issues or difficulty walking.
• Weakness on one side of your body.

Symptoms of chronic subdural hematoma may also include:

• Memory loss.
• Disorientation.
• Personality changes.

A baby with a subdural hematoma may have an enlarged head. This is because their soft skull can enlarge as blood collects.

Get immediate medical help if you or a loved one have these symptoms.

As bleeding continues and the pressure in your brain increases, symptoms can get worse. Severe symptoms include:

• Paralysis.
• Seizures.
• Breathing problems.
• Loss of consciousness (passing out).
• 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, stroke or dementia.

Any time you experience neurological symptoms, like memory loss, dizziness or muscle weakness, you should see a healthcare provider. Try to give them as much information as possible about when and how your symptoms started.

What causes subdural hematomas?

Head injuries cause most subdural hematomas. Examples of how this could happen include:

• Falling and hitting your head.
• Taking a blow to your head in a car or bike accident.
• Hitting your head while playing sports.
• Getting a head injury from an assault or physical abuse.

What are the risk factors for subdural hematoma?

Anyone can get a subdural hematoma from an accidental head injury. But certain factors can increase your risk, including:

• Age: People 65 and older and babies are more at risk for getting subdural hematomas. As you age, your brain shrinks inside your skull. The space between your skull and brain widens. This makes the tiny veins in the membranes between your skull and brain stretch. These thinned, stretched veins are more likely to tear, even if you experience a minor head injury. Babies don’t have strong neck muscles to protect themselves from head trauma. When someone shakes a baby forcefully, they can develop a subdural hematoma (shaken baby syndrome).
• Playing contact sports: People who play high-impact or extreme sports (like football, rugby or snowboarding) have an increased risk of a subdural hematoma.
• Taking blood thinners: Blood thinners (anticoagulants) slow down your clotting process or prevent blood from clotting at all. If your blood doesn’t clot, bleeding around your brain can be severe and long-lasting, even after a relatively minor injury.
• Hemophilia: This is an inherited bleeding disorder that prevents your blood from clotting. People with hemophilia have a higher risk of uncontrolled bleeding after an injury.
• Alcohol use disorder: Drinking excessive amounts of alcohol causes liver damage over time. A damaged liver can’t produce enough of the proteins that help your blood clot. This increases your risk of uncontrolled bleeding.

How is subdural hematoma diagnosed?

A healthcare provider will do a thorough physical and neurological exam. They’ll ask about:

• Your symptoms.
• How and when your head injury happened.
• Underlying health conditions you have.
• Medications you take.

If the provider thinks you may have a subdural hematoma, they’ll order an imaging test of your head. This may be a computed tomography (CT) scan and/or a magnetic resonance imaging (MRI) scan. These tests allow providers to see clear pictures of your brain and determine the location and amount of bleeding. They can also show other head and neck injuries.

How are subdural hematomas treated?

In an emergency, healthcare providers will stabilize your breathing and other vital signs.

For large or severe subdural hematomas, you usually need surgery. There are two main types:

• Craniotomy: A neurosurgeon temporarily removes a section of your skull so they can access and remove the hematoma. This is the main treatment for acute subdural hematomas.
• Burr holes: A neurosurgeon drills one or more small holes into your skull. They insert a tube through the hole to help drain the blood. They typically leave a drain in place for several days following surgery to allow the blood to continue draining. This is the main treatment for chronic subdural hematomas.

Sometimes, hematomas cause few or no symptoms and are small enough that they don’t require surgical treatment. Rest, medications and observation may be all that you need. Your healthcare provider may order regular imaging tests (such as an MRI) to monitor the hematoma and make sure it’s healing.

Possible surgery complications

Like all surgeries, craniotomies and burr hole surgeries carry a risk of complications. Most of these complications are uncommon, but they can be serious.

Problems that can develop after subdural hematoma surgery include:

• Further bleeding on your brain.
• Infection.
• A blood clot in your leg (deep vein thrombosis).
• Seizures.
• Stroke.

Recovering from a subdural hematoma

The length of time it takes to recover from a subdural hematoma varies from person to person. Your healthcare provider can tell you what to expect based on your unique situation. Some people feel better a few weeks after treatment, while others may never make a full recovery.

If you have persistent symptoms after surgery like memory problems or weakness, you may need further treatment to help you gradually return to your normal activities.

You may have several healthcare providers as a part of your rehabilitation, including:

• Physical therapists: A physical therapist helps you improve how your body performs physical movements. They’ll help you manage symptoms like pain or weakness that make it hard to move.
• Occupational therapists: An occupational therapist helps you improve your ability to do daily tasks. They’ll help you learn how to stand, sit or use different tools to participate in your activities safely.
• Speech-language pathologists (SLPs): SLPs provide education and training to address speech, language, voice and swallowing disorders.

What is the prognosis for someone with a subdural hematoma?

If you have a subdural hematoma, your prognosis (outlook) depends on:

• Your age.
• The severity of your head injury.
• How quickly you received treatment.

About half of people with large acute hematomas survive, but they often have permanent brain damage. Younger people have a higher chance of survival than older adults.

In some cases, the hematoma can come back during the days or weeks after surgery. If this happens, you may need another surgery.

People with chronic subdural hematomas usually have the best prognosis, especially if they have few or no symptoms and remained awake and alert after the head injury.

What are the complications of subdural hematoma?

Without treatment, large hematomas can lead to coma and death. Other complications include:

• Brain herniation: Increased pressure from a pool of blood can squeeze and push brain tissue so it moves from its normal position. A brain herniation is often fatal.
• Repeated bleeding: People older than 65 who are recovering from a hematoma have a higher risk of another hemorrhage due to changes in their brain tissues.
• Seizures: Seizures may develop even after you receive treatment for a hematoma.

Children with severe hematomas may have developmental delays from permanent brain damage.