Second Impact Syndrome

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan.


Second impact syndrome (SIS), or repetitive head injury syndrome, describes a condition in which individual experiences a second head injury before complete recovery from an initial head injury. Recently SIS has gained increased attention as many cite athletes sustaining a concussion and returning to the sport early as being particularly at risk. Though it is a relatively rare condition, physicians should be aware of SIS, and educate patients who have experienced or are at risk of experiencing a head injury, as the syndrome is often deadly. The term second impact syndrome entered the medical lexicon in 1984 when Saunders and Harbaugh wrote an article describing a case report of a football player who died four days after suffering a head injury after he returned to play on the day of his death. He collapsed and died after a presumed second head injury.

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