Health A-Z

Medical Content Created by the Faculty of the Harvard Medical School


What Is It?

A subdural hematoma occurs when a blood vessel near the surface of the brain bursts. Blood builds up between the brain and the brain's tough outer lining. The condition is also called a subdural hemorrhage.

In a subdural hematoma, blood collects immediately beneath the dura mater. The dura mater is the outermost layer of the meninges. The meninges is the three-layer protective covering of the brain.

A subdural hematoma is a life-threatening problem because it can compress the brain.

Most subdural hemorrhages results from trauma to the head. The trauma damages tiny veins within the meninges.

In young, healthy people, bleeding usually is triggered by a significant impact. This type of impact might occur in a high-speed motor vehicle accident.

In contrast, older people may bleed after only a minor trauma. For example, it might happen from falling out of a chair.

A subdural hematoma is also more common in people:

  • Taking medications that thin the blood

  • Who abuse alcohol

  • Who have seizures

An acute subdural hemorrhage is bleeding that develops shortly after a serious blow to the head. Blood accumulates rapidly, causing pressure to rise within the brain. This can result in loss of consciousness, paralysis or death.

When bleeding develops slowly, it is known as a chronic subdural hemorrhage. Bleeding may develop over a period of weeks to months

This form of bleeding is much more common in older people. The head trauma that causes chronic subdural hemorrhage is often minor. Many of those affected cannot recall a head injury.

Page 1 of 9     Next Page:  Subdural Hematoma Symptoms
Click here to to redeem your SparkPoints
  You will earn 5 SparkPoints
From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.

You can find more great health information on the Harvard Health Publications website.