(Extra-axial Haematoma; Subdural Haemorrhage; SDH)
How to Say It: sub-dur-al hee-ma-toe-ma
by Cynthia M. Johnson, MA
A hematoma is a collection of blood. A subdural hematoma (SDH) happens in the space between the covering of brain (the dura) and the brain. It can put pressure on the brain.
SDH is most often caused by a head injury. This may be due to traumas such as car accidents, assault, and falls.
This problem is more common in men, older adults, infants, and toddlers, and people on blood-thinning medicines. Other things that may raise the risk are:
The blood may pool quickly or take some time to build up. This will affect how fast symptoms happen.
Problems may be:
You will be asked about your symptoms and health history. A physical exam will be done.
Pictures may be taken of the brain and the structures around it. This can be done with:
Treatment will depend on the size and severity of the SDH. It will also depend on the symptoms a person is having. Options are:
This problem is often caused by a head injury. These can be hard to prevent.
American Academy of Otolaryngology—Head and Neck Surgery
Brain Injury Association of America
Brain Injury Canada
Ontario Brain Injury Association
Fomchenko EI, Gilmore EJ, et al. Management of Subdural Hematomas: Part I. Medical Management of Subdural Hematomas. Curr Treat Options Neurol. 2018 Jun 23;20(8):28.
Subdural hematoma. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/subdural-hematoma. Accessed October 7, 2020.
Subdural haematoma. Patient UK website. Available at:
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Accessed October 7, 2020.
Last reviewed September 2020 by EBSCO Medical Review Board Rimas Lukas, MD
Last Updated: 5/25/2021