by EBSCO Medical Review Board
(Extra-axial Haematoma; Subdural Haemorrhage; SDH)


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.

Head Injury
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Risk Factors

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:

  • Headache
  • Changes in thinking or behavior
  • Bruising around the head or eyes
  • Vision problems
  • Speech problems
  • Loss of consciousness


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:

  • Monitoring the injury for changes
  • Medicines to ease brain swelling, such as steroids
  • Surgery to ease pressure on the brain


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: Accessed October 7, 2020.

Subdural haematoma. Patient UK website. Available at: Accessed October 7, 2020.

Revision Information

  • Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
  • Review Date: 09/2020
  • Update Date: 05/25/2021