Epidural vs. Subdural Hematomas: What Are They?

Nothing can give you pause quite like hearing that you have blood collecting in your brain. But where that blood is and why it’s there can make a big difference in what comes next.

Knowing the differences between epidural and subdural hematomas can help you fully understand your diagnosis.

We talked with neurosurgeon Nina Moore, MD, about the similarities and differences.

Epidural hematoma vs. subdural hematoma

Epidural hematomas and subdural hematomas are both conditions where blood has pooled and clotted around your brain. The location of the bleed determines which condition it is:

• Epidural hematomas form in the space between your skull and the outermost layer of meninges, the dura mater. Dura mater helps protect your brain.
• Subdural hematomas are deeper. They form between the dura mater and brain — specifically, the second meningeal layer, the arachnoid layer. They’re more common than epidural hematomas.

“The dura mater is like a bag that holds and protects your brain,” Dr. Moore illustrates. “It’s a thick membrane, a little bit thicker than a sheet of paper. If the hematoma is outside of that layer, it’s epidural. If it’s underneath it, it’s subdural.”

Symptoms of epidural vs. subdural hematoma

Your care team will use brain imaging, like CT scans, to identify hematomas — but your symptoms and what triggers them can be a clue as to what’s happening.

Epidural hematoma symptoms

Epidural hematomas are typically the result of head trauma. That can include things like car accidents, sports injuries or acts of violence. But you may not show symptoms immediately following your injury.

“The classic teaching is that people with an epidural hematoma usually are awake and feeling fine for a period of time after an injury happens. Then, they decline suddenly,” Dr. Moore says.

That decline may include concussion-like symptoms, including:

• Severe headaches
• Nausea
• Vomiting
• Slurred speech
• Dizziness
• Weakness

Some people may even lose consciousness or experience seizures. They can be deadly if untreated.

These risks and others are a good reminder to take any head injury seriously. Seek emergency care by calling 911 (or emergency services in your country) if you show any troubling symptoms.

Subdural hematoma symptoms

Subdural hematoma symptoms can be more subtle, and they have a wider range of causes.

“They aren’t always caused by trauma,” Dr. Moore explains. “They can also result from natural changes in the brain over time. For example, older adults’ brains tend to shrink slightly with age, which can put tension on the veins. Abnormal blood vessels, low blood counts and taking blood thinners can also increase your risk.”

That all can mean that they can linger and grow. Typical signs include:

• Headaches
• Nausea
• Confusion
• Weakness

Over time, a subdural hematoma that’s not addressed can lead to:

• Memory loss
• Personality changes
• Disorientation
• Seizures
• Losing consciousness

Treating epidural and subdural hematomas

Epidural hematomas usually require emergency surgery. Subdural hematomas may require surgery, but not always. Your provider’s recommendations will vary depending on the size of the hematoma and how it affects you.

“Epidural hematomas can progress quickly and are typically treated as a neurosurgical emergency,” Dr. Moore reports. “For subdural hematomas, there can be other options, especially if it’s small or chronic (been there for a while).”

The most common surgery for epidural hematomas is a craniotomy, which involves removing a portion of the skull and clearing out the blood clot.

If you have a subdural hematoma, your team may advise a craniotomy or treatments like:

• Burr holes: A surgeon drills a small hole or holes into your skull and inserts a tube to allow blood to drain.
• Middle meningeal embolization: A surgeon guides a catheter through an artery to the site of the hematoma and blocks the end of the vessel to stop the bleeding.
• Watchful waiting: If it’s small, new and isn’t causing severe symptoms, it may resolve on its own. Your team may recommend waiting and re-imaging at a later date to see if your body absorbs the clot without intervention.

Which is worse: Epidural vs. subdural hematoma?

Hematomas can be dangerous, no matter where they’re located or how they form.

But epidural hematomas that form after a head injury can be particularly dangerous. They’re medical emergencies that can grow quickly and cause you to lose consciousness suddenly.

On the other hand, subdural hematomas, even those that develop slowly, can bring their own set of dangers.

Think about it: You’re probably very likely to seek medical care if you have a pounding headache after, say, falling off a ladder. That can mean getting care quickly.

But if you have a headache that comes on without any clear reason, it may be easier to brush off. It can be a sign of a subdural hematoma from a long-growing brain bleed. But without a clear trigger, it can be hard to pinpoint the cause of such a nonspecific symptom. So, you may be less likely to seek care quickly. And even when you do seek treatment, checking for a subdural hematoma may not be your provider’s first inclination. That can make subdural hematomas tougher to find, which can increase your risk for complications. That may be one reason why survival rates are lower for people with subdural hematomas.

Bottom line: Hematomas warrant expert diagnosis and care. Talk with a healthcare provider about concerning symptoms and seek prompt care for head injuries.