A subdural hematoma develops when bridging veins tear and leak blood. These are the tiny veins that run between the dura and surface of the brain. This is usually the result of a head injury.

A collection of blood then forms over the surface of the brain. In a chronic subdural collection, blood leaks from the veins slowly over time, or a fast hemorrhage is left to clear up on its own.

A subdural hematoma is more common in older adults because of normal brain shrinkage that occurs with aging. This shrinkage stretches and weakens the bridging veins. These veins are more likely to break in older adults, even after a minor head injury. You or your family may not remember any injury that might have caused a subdural hematoma.

Risks include:

• Long-term heavy alcohol use
• Long-term use of aspirin, anti-inflammatory medicines such as ibuprofen, or blood thinning (anticoagulant) medicine such as warfarin
• Diseases that lead to reduced blood clotting
• Head injury
• Old age

In some cases, there may be no symptoms. However, depending on the size of the hematoma and where it presses on the brain, any of the following symptoms may occur:

• Drowsiness, confusion, or coma
• Decreased memory
• Problem speaking or swallowing
• Problems with balance or walking
• Headache
• Seizures or loss of consciousness
• Weakness or numbness of arms, legs, face
• Nausea and vomiting
• Vision problems
• Behavioral changes or psychosis

Your health care provider will ask about your medical history. Your physical exam will include a careful check of your brain and nervous system for problems with:

• Balance
• Coordination
• Mental functions
• Sensation
• Strength
• Walking

If there is any suspicion of a hematoma, an imaging test, such as a CT or MRI scan will be done.

The goal of treatment is to control symptoms and reduce or prevent permanent damage to the brain. Medicines may be used to control or prevent seizures.

Surgery may be needed. This may include drilling small holes in the skull to relieve pressure and allow blood and fluids to be drained. Large hematomas or solid blood clots may need to be removed through a larger opening in the skull (craniotomy).

Hematomas that do not cause symptoms may not require treatment. Chronic subdural hematomas often come back after being drained. Therefore, it is sometimes better to leave them alone unless they are causing symptoms.

Chronic subdural hematomas that cause symptoms usually do not heal on their own over time. They often require surgery, especially when there are neurologic problems, seizures, or chronic headaches.

Complications may include:

• Permanent brain damage
• Persistent symptoms, such as anxiety, confusion, difficulty paying attention, dizziness, headache, and memory loss
• Seizures

Contact your provider right away if you or a family member has symptoms of chronic subdural hematoma. For example, if you see symptoms of confusion, weakness, or numbness weeks or months after a head injury in an older adult, contact the provider right away.

Take the person to the emergency room or call 911 or the local emergency number if the person:

• Has seizures
• Is not alert (loses consciousness)

Avoid head injuries by using seat belts, bicycle and motorcycle helmets, and hard hats when appropriate.

Subdural hemorrhage - chronic; Subdural hematoma - chronic; Subdural hygroma

Kolias AG, Taisic T, Chari A, Hutchinson PJ, Santarius T. Medical and surgical management of chronic subdural hematomas. In: Winn HR, ed. Youmans and Winn Neurological Surgery. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 47.

Papa L, Goldberg SA. Head trauma. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 33.

Stippler M, Mahavadi A. Craniocerebral trauma. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 62.

Updated by: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.