A subdural hematoma (SDH) is a collection of blood that clots in the subdural region of the brain. This region is a space between the skull and the outside of the head. The pooling of blood puts pressure on the brain. SDH can be classified by the time between the trauma and symptoms:

  • Acute—less than 48 hours
  • Subacute—2-12 days
  • Chronic—more than 12 days

This can be serious and life-threatening. It requires care from your doctor.


SDH is most often caused by:

  • Head injury due to trauma (eg, from falls or car accidents)

Head Injury

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Risk Factors

The following factors increase your chance of developing a SDH:

If you have any of these risk factors, tell your doctor.


If you have any of these symptoms, do not assume it is due to SDH. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:

  • Loss of consciousness
  • Bruising around the head or eyes
  • Headache
  • Nausea or vomiting
  • Personality changes
  • Limb weakness
  • Fatigue/sleepiness
  • Confusion
  • Speech difficulties
  • Visual impairment


Your doctor will ask about your symptoms and medical history. She will also do a physical exam. You may be referred to a neurologist for special testing.

Tests may include:

  • CT scan—a type of x-ray that uses a computer to make pictures of structures inside the head
  • MRI scan—a test that uses magnetic waves to make pictures of structures inside the head
  • Blood tests
  • Neurological examination
  • EEG (electroencephalogram)—a noninvasive test used to evaluate brain function


Talk with your doctor about the best treatment plan for you. Treatment will depend on:

  • Symptoms
  • Size and severity of the hematoma

Treatment options include the following:

Monitoring and Observation

For minor injury with little or no symptoms, your doctor may advise that you watch for symptoms to develop in the days and weeks that follow.

Neuropsychological Testing

You may need more testing done. These tests assess how your brain functions. The results can help your doctor determine:

  • How you are recovering
  • Whether you are ready to return to high-impact activities


In some cases, your doctor may prescribe antiseizure medication.


This usually involves making “burr holes” in the scalp and skull and draining the clotting blood. Sometimes a section of the skull is removed to relieve pressure. This is called a craniotomy.


To help reduce your chance of SDH, take these steps:

  • Wear proper helmets when playing sports.
  • Reduce the risk of fall or injury. Safeguard your home and workplace.
  • Have regular blood tests if you are taking blood thinning medicine.
  • Limit your alcohol intake to a moderate level. This means:
    • Two or fewer drinks per day for men
    • One or fewer drinks per day for women