IED blast postconcussive syncope and autonomic dysregulation.

Concussions are the most frequent battle injury sustained in Afghanistan. The Concussion Restoration Care Center provides multidisciplinary care to concussed service members in theater. The Concussion Restoration Care Center has managed over 500 concussions, the majority being from improvised explosive device (IED) blasts. Syncope following a concussion without a loss of consciousness is rarely reported in the literature. The pathophysiology of concussion from a blast injury may be distinct from a concussion secondary to blunt trauma. Two cases of syncope following concussions with an alteration of consciousness are presented, and a mechanism of action is proposed. Post-IED blast concussive symptom frequency at initial presentation on a cohort of patients is reported, with 1.3% of patients experiencing postconcussive syncope. Syncope following an IED blast may be related to centrally mediated autonomic dysregulation at the brain stem level. Syncope should be added to the list of possible symptoms that occur following concussions, in particular concussions following a blast injury.