Every year, thousands of Danes are treated in emergency departments after a blow to the head. The vast majority recover without lasting damage, but a smaller group develops epilepsy in the months or years following the accident. 

Until now, doctors have had only limited knowledge of who is at particular risk. But a new Danish study suggests that a common blood test, already taken routinely in many emergency departments, may help identify the most vulnerable patients.

"Our study indicates that S100B levels in people with head trauma can be used to assess who is at particular risk of developing epilepsy," says postdoc Kasper Lolk from the Department of Public Health at Aarhus University, who led the study.

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

Particularly relevant in cases of visible brain damage

S100B is a protein 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.

"S100B levels correlate with the severity of traumatic brain injury, which is also the most important risk factor for post-traumatic epilepsy. It is therefore not unexpected that the association is seen primarily in patients with detectable brain lesions," explains Jakob Christensen, clinical professor in epilepsy at the Department of Clinical Medicine at Aarhus University.

Pre-existing conditions increase vulnerability

The study also showed that patients with certain pre-existing conditions were at particularly high risk. This was especially true for individuals with cerebrovascular disease and alcohol misuse.

"Our study suggests that pre-existing conditions can make the brain more vulnerable to the consequences of head trauma. Cerebrovascular disease and alcohol misuse can both increase the risk of bleeding after head trauma, and brain haemorrhage in particular is associated with a markedly elevated risk of subsequent epilepsy," says Jakob Christensen.

Further studies needed

The researchers emphasise that additional research is needed before S100B can be adopted as a prognostic tool in clinical practice. More precise information is needed regarding the extent of brain damage and the timing of blood sampling, and the results need to be confirmed in other studies.

"In the short term, further studies are needed to examine the significance of S100B in greater 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.

Behind the research findings

• Study type: Prospective, register-based cohort study
• Collaborators: Department of Neuroscience and Physiology, University of Gothenburg, Gothenburg; Neurology Services, Sahlgrenska University Hospital, Gothenburg
• External funding: The Lundbeck Foundation, Novo Nordisk Foundation.
• Potential conflicts of interest: Jakob Christensen has received honoraria for participation in scientific advisory boards and lecture activities for UCB Nordic and Eisai, and has received travel support from UCB Nordic.
• Link to scientific article: https://onlinelibrary.wiley.com/doi/10.1002/epi.70049?af=R

Contact 

Postdoc Kasper Lolk
Aarhus University, Department of Public Health
lolk.ncrr@au.dk 
Phone: 87166296