Blast Injuries

U.S. Army photo by Sgt. Gustavo Olgiati

How do explosive blasts cause a TBI?

  • Blasts from various forms of improvised explosive devices (IEDs) are a common cause of combat-related injury in the military and were the most common cause of combat-related concussions during Operation Enduring Freedom and Operation Iraqi Freedom
  • There are four different mechanisms through which a blast can cause injury:
    • Primary injury: Atmospheric over-pressure followed by under-pressure or vacuum
    • Secondary injury: Objects placed in motion (shrapnel) by the blast hitting the service member
    • Tertiary injury: Service member being thrown by the blast and hitting their head against the ground, a wall, or other solid surface
    • Quaternary injury: Other injuries from the blast such as burns and crush injuries
  • For passengers in vehicles hit by a blast, such as an IED, it’s common to sustain both a primary and tertiary injury

Does a blast cause different brain injuries than blunt trauma?

  • There currently is no evidence to suggest significant differences between blast and blunt injury:
    • MRI imaging studies, such as diffusion tensor imaging, don’t indicate microstructural differences
    • No cognitive differences have been identified between blunt and blast induced concussions

How should TBI from a blast injury be treated?

  • Since most evidence suggests that blast and blunt TBI are very similar, there’s no difference in the treatment
  • All service members who sustain a concussion following a blast are thought to have injury not only from the blast, but also from blunt trauma