What Is a Subdural Hematoma and Why Does It Occur?

A subdural hematoma usually goes unnoticed because it occurs between the surface of the brain and its outer covering. Today we will find out what causes it to appear.
What Is a Subdural Hematoma and Why Does It Occur?

Last update: 27 December, 2022

A subdural hematoma is an accumulation of blood between the surface of the brain and its outer covering, known as the dura mater. Its appearance can cause different complications, which, if not treated, can lead to death.

To detect a subdural hematoma, a CT or MRI scan is needed. However, paying attention to certain symptoms can also alert us to its presence:

  • Slurred speech and the inability to pronounce words correctly.
  • Problems with balance and difficulty walking.
  • Headaches with nausea and vomiting.
  • Seizures or loss of consciousness.
  • Weakness or numbness of the extremities.

Faced with any of these symptoms, it’s best to go to the doctor or emergency room as soon as possible. A subdural hematoma is an emergency situation that should be treated as soon as possible.

The causes of a subdural hematoma

We have already seen the symptoms that alert us to the presence of a subdural hematoma. However, we will now turn our attention to the possible causes that can lead to it.

Severe head injury

One of the main causes is a severe head injury. Due to a traffic accident, a physical assault, a fall in which we have hit our head, or an accident at work, we may have done much more damage than we thought.


Subdural hematomas produced by these circumstances may disappear spontaneously.

However, those that don’t won’t manifest any symptoms until weeks later. Older people who fall frequently are more at risk of getting a subdural hematoma. Repeated falls can lead to repetitive head trauma with serious consequences.

Anticoagulant drugs

Some anticoagulant drugs, such as heparin or warfarin, can contribute to the development of a subdural hematoma. These drugs are intended to prevent the formation of clots.

If someone takes these drugs and suffers a fall, the risk of hematoma increases. The reason is that after the blow and the venous rupture that this will trigger, the blood won’ stop flowing. Therefore, it will accumulate in the subdural space and rapidly increase in size.


Older people aren’t only at risk of suffering a subdural hematoma due to falls. There’s another reason why they’re more susceptible.

Aging causes the brain to shrink, causing it to pull on the dura mater, drawing it into itself. This causes the blood vessels to stretch, making them more fragile and prone to tearing.

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Certain diseases such as cancer or liver disease can weaken the blood vessels. This makes them much more vulnerable to suffering a subdural hematoma in an accident, fall, or blow.

If we have experienced some of the above causes and we have nausea, headaches, fainting or balance problems, it would be advisable to visit the doctor. In this way, you would rule out a possible subdural hematoma.

Subdural hematomas in children

If a child has a subdural hematoma and the parents are acting suspiciously, then a possible case of child abuse should be investigated.

Repeated blows to children can eventually cause a hematoma of this type. Therefore, doctors will always investigate and analyze the situation to rule out any possible suspicion of abuse.

If there’s no evidence of abuse within the home, they will try to find out if the child is a victim of bullying or has been involved in a fight recently. A fall or a blow with some kind of instrument can also cause a subdural hematoma.

Despite this, we must bear in mind that children tend to fall regularly and hit themselves quite often when they play. Therefore, once we have ruled out all the above options, we can verify that the hematoma is the result of a circumstance unrelated to any kind of abuse.

Remember that at the slightest suspicion that we may have a subdural hematoma, we should ask for help as soon as possible. If we don’t do this, the pressure in the brain will increase to such an extent that it could cause us to go into a coma. In the most serious cases, it can even cause death.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Papa L, Goldberg SA. Head trauma. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 34.
  • Ducruet, A. F., Grobelny, B. T., Zacharia, B. E., Hickman, Z. L., DeRosa, P. L., Anderson, K., … Connolly, E. S. (2012). The surgical management of chronic subdural hematoma. Neurosurgical Review. https://doi.org/10.1007/s10143-011-0349-y
  • Stippler M. Craniocerebral trauma. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley’s Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier; 2016:chap 62

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.