second impact syndrome


A rare but catastrophic condition seen in boxing and other ‘head-impact’ sports, which occurs in 2 phases: (1) a concussion or cerebral contusion due to blunt trauma to the head which causes headaches, impaired cognition, incoordination, and decreased speech and motor functions; (2) further trauma—i.e., a second blow or impact—however minor, before the parenchymal changes caused by the first concussion have completely resolved, may cause a coma or sudden death due to cerebral oedema. Most common in young athletes, it is often fatal or leaves the victim with severe neurologic residua
Aetiology Unknown. It has been attributed to dysregulation of the intracranial arterioles

second impact syndrome

Sports medicine A catastrophic condition associated with boxing and other 'head-impact' sports, which occurs in 2 phases; a concussion or cerebral contusion 2º to blunt trauma to the head causes headaches, impaired cognition, incoordination, and ↓ speech and motor functions; if further trauma–ie, a 2nd impact occurs before the Sx resolve, a 2nd blow or impact, however minor, may cause coma or sudden death due to cerebral edema. See Boxing, Concussion, Ultimate fighting.