Traumatic brain injury (TBI) is a complex management condition.Mild to moderate presentation is dealt with mostly in a non-ICU setting, while severe TBI ends up in intensive care units.The presentation and course of severe TBI is a team effort, and attempts are made to prevent complications and reduce morbidity.One condition which is still not clear and usually presents after initial stabilization is sympathetic overactivity.Here we will try to go over unanswered questions about this condition.We do not believe that the suggested answers to these questions are all set in stone and will change as we have a better understanding.