Blood test may help predict epilepsy after head trauma

A common blood test already used in many Danish emergency departments may help doctors identify patients who have an increased risk of developing epilepsy after a head injury. This is shown by a new study from researchers at Aarhus University.

Every year, thousands of Danes are treated in emergency departments after a blow to the head. Most recover without lasting consequences, but a smaller group develop epilepsy in the months or years after the accident. Until now, doctors have had limited knowledge about who is most at risk.

According to the researchers, the protein S100B, which is measured in the blood of many patients with head trauma, may be used to assess the risk.

“Our study suggests that the S100B level in people with head trauma can be used to assess who is at particular risk of developing epilepsy,” says postdoctoral researcher Kasper Lolk from the Department of Public Health at Aarhus University.

The study includes more than 10,000 Danes who had the protein S100B measured in their blood after a head injury between 2013 and 2022.

Particularly relevant in cases with visible brain injuries
S100B is a protein that is released from brain cells when an injury occurs. In Danish emergency departments, the measurement is already used to assess whether patients with minor head injuries need a CT scan.

The researchers found that elevated S100B levels were associated with an increased risk of epilepsy – but only in patients who also had detectable lesions in the brain.

In this group, patients with high S100B levels had up to a 21 percent risk of developing epilepsy within five years.

“The S100B level correlates with the severity of traumatic brain injury, which is also the most important risk factor for post-traumatic epilepsy. Therefore, it is not surprising that the association is mainly seen in patients with detectable brain lesions,” explains Jakob Christensen, clinical professor of epilepsy at the Department of Clinical Medicine at Aarhus University.

Existing diseases increase vulnerability
The study also shows that patients with certain existing diseases have a particularly high risk of developing epilepsy after a head trauma.

This includes people with cerebrovascular diseases and people with alcohol abuse.

“Our study suggests that existing diseases may make the brain more vulnerable to the consequences of head trauma. Cerebrovascular diseases and alcohol abuse can both increase the risk of bleeding after head trauma, and brain hemorrhage is associated with a significantly increased risk of subsequent epilepsy,” says Jakob Christensen.

Need for more research
The researchers emphasize that further studies are needed before the measurement of S100B can be used as a prognostic tool in clinical practice.

Among other things, more precise knowledge is needed about the extent of brain injuries and the timing of blood sampling. The results also need to be confirmed in other studies.

“In the short term, there is a need for additional studies that examine the significance of S100B in more detail. In the longer term, the hope is that this knowledge can be used to prevent the development of epilepsy in people who have suffered a head injury,” says Kasper Lolk.