A study led by the University of Glasgow has revealed differences in the brains of paediatric and adult patients that might explain the sometimes catastrophic outcomes seen in children following a traumatic brain injury.

In findings published in the journal JAMA Network Open, the researchers found the first pathological evidence that the pattern of damage to blood vessels after a severe brain injury appears to be age-dependent. Specifically, in adult brains, vessels showing signs of damage after trauma were often medium or larger-sized. In contrast, in paediatric patients, it was typically the smallest-sized vessels (capillaries) that were damaged.

For the study, the researchers studied postmortem brain tissue samples from 81 paediatric patients (aged 3-18 years) and 62 (aged 19 or over) adults who died shortly after sustaining a traumatic brain injury.

In addition to the vascular pathology, severe brain swelling was far more common among the paediatric cases examined, which the authors suggest might be a result of the differences in blood vessel damage seen after trauma.

Traumatic brain injury represents the leading cause of death and permanent disability in young children and adolescents. Compared to adults, there is an increased risk of catastrophic outcomes in younger patients following TBI, including diffuse brain swelling and so-called second impact syndrome. However, up until now, the cause of these poorer outcomes in paediatric patients was unclear.

Led by consultant neuropathologist Prof. Willie Stewart, Honorary Professor at the University of Glasgow, the study provides crucial information on important differences in the response of brain blood vessels to injury in paediatric and adult patients.

Prof. Stewart said, "This research has considerable implications in terms of understanding TBI in younger people. In contrast to adults, paediatric patients appear especially vulnerable to catastrophic outcomes, which can arise following all injury severities, including mild TBI or concussion. Given this, further research in this area is needed.

"In the meantime, these findings reinforce the reasoning behind our, 'If in doubt, sit them out' approach to concussion management, especially with younger players and in sports like rugby."

In previous findings by Prof. Stewart and collaborators, researchers found that former international rugby players had an approximately 2.5-times higher risk of neurodegenerative disease than expected, with risk of disease varying by subtype, but not by player position. In the FIELD study, the research team reported the first data on neurodegenerative risk among former professional footballers.

In parallel work, also led by Professor Stewart, a specific pathology linked to brain injury exposure, known as chronic traumatic encephalopathy (CTE), has been described in a high proportion of the brains of former contact sport athletes, including former rugby players.