Subdural hematomas are most frequently the result of a head injury. They can occur spontaneously in the elderly, but this is less common. Traumatic subdural hematomas are among the most lethal of all head injuries.

Subdural hematomas are seen in approximately 15% of all head traumas. Tiny "bridging veins" that run between the surface of the brain and its outer covering (dura) stretch and tear, allowing blood to collect. These veins rupture because of the sudden change in velocity of the head during the trauma.

Acute, subacute, and chronic are all adjectives used to describe subdural hematomas and reflect the time course of the collection of blood. Traumatic acute subdural hematomas carry the highest risk to the patient, with a mortality rate of greater than 50% in most studies.

Risks include:

• Head injury
• Very young or very old age
• Anticoagulant medication (blood thinners)
• Chronic alcohol use

• Recent injury or trauma to the head
• Loss of consciousness after original injury
• Headache, steady or fluctuating
• Weakness, numbness or inability to speak
• Slurred speech
• Nausea and vomiting
• Lethargy
• Seizures

In infants:

• Bulging fontanelles
• Increased head circumference
• Separated sutures
• Irritability
• High-pitched cry
• Focal seizures
• Generalized tonic-clonic seizure

Always seek medical attention following a significant head trauma. The evaluation should include a complete neurologic exam.

Signs of weakness, numbness, inabilty to speak, slurred speech, or abnormal level of consciousness will prompt the physicial to order a brain imaging study. A CT scan or MRI scan will be done to evaluate for the presence of a subdural hematoma.

A subdural hematoma is an emergency condition! Treatment goals include lifesaving measures, control of symptoms, and minimizing or preventing permanent brain damage. Lifesaving measures may include support breathing and/or circulation.

Medications prescribed vary according to the type and severity of symptoms and the extent of brain damage. Diuretics may be used to reduce swelling. Anticonvulsant medications such as phenytoin may be used to control or prevent seizures.

Emergency surgery may be required to reduce pressure within the brain. This may involve drilling a small hole in the skull to relieve pressure and allow drainage of the hematoma. Large hematomas or solid blood clots may need to be removed through a larger opening in the skull (craniotomy).

The outlook following a subdural hematoma varies widely depending on the mechanism of head injury, the size of the subdural collection, and how quickly treatment is obtained.

Acute subdural hematomas present the largest challenge, with high rates of death and injury. Subacute and chronic subdural hematomas have good outcomes in most cases, with symptoms going away after drainage of the blood collection. There is a high frequency of seizures following subdural hematoma; however, these seizures are usually well controlled with medication.

• Temporary of permanent weakness, numbness, difficulty speaking
• Seizures
• Brain herniation
• Persistent symptoms such as memory loss, dizziness, headache, anxiety, and difficulty concentrating

Serious head injuries and complications like subdural hematoma require emergency medical attention. 911 and emergency room services should be used. Often, spinal injuries accompany head injuries, so always consider immobilizing the patient's neck if the patient must be moved before medics arrive.