What is the name of the injury characterized by catastrophic brain swelling after a second concussion before prior symptoms have resolved?

• A. Second impact syndrome
• B. Concussion coma
• C. Chronic traumatic encephalopathy
• D. Post-concussive syndrome

Answer: (A)

Second Impact Syndrome is the name for this scenario. It happens when a second concussion occurs before the first concussion has fully resolved, and the brain’s autoregulation is overwhelmed. The result is rapid, diffuse brain swelling that can lead to brain herniation, coma, and death. The crucial point is the timing: a second impact while the first injury is still unresolved triggers catastrophic edema, unlike a normal concussive event.

This differs from other terms. Chronic traumatic encephalopathy is a long-term degenerative condition from repeated head trauma over years, not an acute swelling after a second injury. Post-concussive syndrome describes persistent but non-emergent symptoms after a concussion, without the explosive swelling caused by a second impact. Concussion coma isn’t a standard diagnosis in this context; the defining feature here is the rapid brain swelling following a second injury before healing. If SIS is suspected, remove the person from activity and seek urgent medical care rather than allowing a return to play.