Acute cerebral oedema
Acute cerebral oedema or ‘second impact syndrome’ has received media attention due to its catastrophic outcomes. Acute cerebral oedema refers to rapid cerebral swelling that can occur when a second concussive injury is sustained during a ‘vulnerable’ period when the brain has not recovered from an initial insult. Animal models have demonstrated that there is a period of vulnerability during which further injury can result in significant axonal injury with associated ion channel damage. It is thought that a second impact may not be needed for the swelling to develop.
The condition is rare and the only available literature consists of case studies which are inadequate to provide a good understanding of the mechanisms and risk factors. Further research is needed to better understand the pathophysiology and risk factors for ‘second impact syndrome’.