What to Know About Subdural Hematoma

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A subdural hematoma describes a type of bleeding that causes irritation and pressure in the brain. It is sometimes also called a subdural hemorrhage.

Subdural hematomas happen in a region called the subdural space. The subdural space is the area between the surface of the brain and the dura, a layer of protective tissue located between the brain and the skull.

This article looks at the symptoms, causes, and treatment of subdural hematoma.

Patient in wheelchair talking to doctor

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Symptoms of a Subdural Hematoma

Most of the time, subdural hematomas are small or medium in size. These do not usually progress to the point where they cause severe symptoms. In some cases, however, a subdural hematoma can become large enough to push against the brain. This can cause significant neurological symptoms.

When symptoms do occur, they can vary depending on the hematoma's size and location. Symptoms can include any combination of the following:

  • Headaches: This is the most common symptom of a subdural hemorrhage because the pressure from the blood on the brain is likely to cause pain.
  • Dizziness
  • Lethargy
  • Loss of consciousness: When a subdural hemorrhage is large, it can disrupt the normal functioning of the brain.
  • Seizures: Severe pressure on the brain can disrupt the brain's normal electrical activity, resulting in a seizure.
  • Weakness of one arm, leg, and/or side of the face: Pressure on one side of the brain may impair strength on the opposite side of the body.
  • Vision changes
  • Confusion

If a subdural hemorrhage involves significant amounts of blood, the pressure can cause a stroke.

In severe cases, significant pressure can lead to loss of consciousness or even death. This can happen if the blood is located near the brainstem, which controls breathing and other important automatic functions.

What Causes a Subdural Hematoma?

A subdural hemorrhage is typically caused by bleeding of a vein.

The bleeding may occur slowly, and might not produce severe symptoms right away. Symptoms may develop over time as the blood gradually puts increasing pressure on the brain.

A subdural hematoma may be caused by:

  • Head trauma
  • A tumor or an infection

It can also occur without a known cause. Blood thinners may increase the chances of subdural hematoma, especially in older adults.

A subdural hematoma that happens without an obvious cause is called a spontaneous hematoma.

How Subdural Hematomas Are Treated

A subdural hematoma may resolve on its own. For people with mild to moderate bleeding, the symptoms will often go away without treatment. Even so, subdural hematomas always need to be evaluated by a healthcare provider, as they can be life-threatening.

If your subdural hematoma does not require treatment, you should avoid strenuous activity while the blood is clearing up. This kind of activity could increase the risk of head trauma.

Sometimes, the blood must be removed through a surgical procedure such as:

During a burr hole procedure, the surgeon drills one or two holes in the skull and drains the hematoma through the dura.

During a craniotomy, the surgeon creates an opening in the skull and removes the blood with suction. Any remaining blood is flushed away and the skull fragment is replaced. 


A subdural hematoma is bleeding that occurs in the space between the brain and the dura. It can be life-threatening if it is large and puts significant pressure on the brain. Symptoms may include dizziness, loss of consciousness, vision changes, and confusion, among others. 

Subdural hematomas may be caused by head injuries or other factors like tumors or infections. They do not always need treatment, but they should always be evaluated by a healthcare provider. Subdural hematomas are often treated with surgery.

A Word From Verywell

A subdural hemorrhage is a significant medical problem, but most people experience good recovery. If you have had a subdural hemorrhage that requires surgical intervention, you might not experience complete recovery until a few months after your procedure.

As you are recovering, you may experience fatigue, headaches, or neurological symptoms that are expected to gradually improve.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Aspegren OP, Åstrand R, Lundgren MI, Romner B. Anticoagulation therapy a risk factor for the development of chronic subdural hematoma. Clin Neurol Neurosurg. 2013;115(7):981-4. doi:10.1016/j.clineuro.2012.10.008

  2. National Library of Medicine. Subdural hematoma.

  3. Johns Hopkins Health. Burr holes.

Additional Reading

By Jose Vega MD, PhD
Jose Vega MD, PhD, is a board-certified neurologist and published researcher specializing in stroke.