Gunshot injuries are challenging conditions because of the unique characteristics of the wounding agents producing soft tissue damage that may be compounded by the formation of an expanding temporary cavity (cavitation). Variations in ballistic performance leading to higher energy transfer by the projectile, including bullet tumbling, deformation, and fragmentation, cause increased soft tissue injury and may also lead to more extensive bone comminution compromising local blood supply. Once life-threatening injuries have been excluded or properly addressed, the emergency management of localized trauma from bullets and shotgun pellets may be complicated due to progressive tissue necrosis within the zone of injury. Additionally, the risk of infection should be tackled, especially in high energy bone injuries. War experience suggests a baseline separation between wounds with limited tissue destruction which can routinely be managed as simple penetrating injuries and those resulting from high energy transfer to the tissues involving a substantial amount of necrotic elements surrounding the wound channel which call for a more aggressive surgical approach. A further justification for such a distinction is the need for antibiotic therapy, which varies according to most studies depending on the wounding mechanism, the nature of the wound, and the extent of tissue injury. The emergency physician should also be aware of the possibility of “bizarre” bullet paths resulting in occult injuries of important anatomic structures.

Gunshot injuries are challenging conditions because of the unique characteristics of the wounding agents producing soft tissue damage that may be compounded by the formation of an expanding temporary cavity (cavitation). Variations in the ballistic performance leading to higher energy transfer by the projectile, including bullet tumbling, deformation and fragmentation, cause increased soft tissue injury and may also lead to more extensive bone comminution compromising local blood supply. Once life-threatening injuries have been excluded or properly addressed, the emergency management of localized trauma from bullets and shotgun pellets may be complicated due to progressive tissue necrosis within the zone of injury. Additionally, the risk of infection should be tackled especially in high energy bone injuries. War experience suggests a baseline separation between wounds with limited tissue destruction which can routinely be managed as simple penetrating injuries and those resulting from high energy transfer to the tissues involving a substantial amount of necrotic elements surrounding the wound channel which call for a more aggressive surgical approach. A further justification for such a distinction is the need for antibiotic therapy, which varies according to most studies depending on the wounding mechanism, the nature of the wound and the extent of tissue injury. The emergency physician should also be aware of the possibility of “bizarre” bullet paths resulting in occult injuries of important anatomic structures.

Craniocerebral firearm injuries are associated with high mortality rates which increase in proportion to the damage to the brain and skull produced by the projectile, as a result of the kinetic energy dissipated during the projectile-tissue interaction. Ballistic factors that contribute to the brain injury are related to the ballistic behavior of the bullet (whether it yaws, tumbles, mushrooms or disintegrates following skull penetration) and its effects. While these injuries are complicated by the creation of bone fragments causing further damage to the brain tissue, the pressure waves generated intracranially as a result of the temporary cavitation phenomenon are the landmark of bullet penetration of the head. Because within the skull there is no mechanism of pressure relief as in other parts of the body during cavitation, the largely incompressible brain tissue sustains the pressure built up, transmitting the pressure wave and causing indirect bone fractures. Although cavitation occurs with low-velocity projectiles too, high-velocity projectiles are capable of high energy transfer secondary to bullet tumbling, mushrooming and often fragmentation, resulting in marked cavitation and more widespread tissue damage. The sudden increase in the intracranial pressure and the transient deformation of the brain tissue contributes to the development of diffuse brain edema and the cardiac and respiratory centers of the brainstem when not involved in the path of the bullet can still be affected indirectly by the pressure transmission with catastrophic results. Shotgun injuries to the head at close range cause extensive destruction of the brain involving a different mechanism, as the pellets enter the cranial cavity bunched together, thus acting as a single projectile of large diameter.

Craniocerebral firearm injuries are associated with high mortality rates as a result of the kinetic energy deposition during the projectile–tissue interaction and its consequences, causing immediate and delayed brain damage. Ballistic factors that contribute to brain injury from bullets are related to the behavior of the projectile (whether it yaws, tumbles, mushrooms or disintegrates following skull penetration) and the creation of bone fragments from the entry site. Pressure waves generated intracranially associated with the temporary cavitation are the hallmark of bullet penetration of the head. Because of the absence of any compensatory mechanism to absorb the transient pressure loading, the largely incompressible brain tissue is subjected directly to its effects. The sudden increase in intracranial pressure and the resultant deformation of the brain during cavitation contributes to the development of brain edema and may affect the cardiac and respiratory centers of the brainstem, even if not transected by the bullet trajectory. Shotgun injuries to the head at close range cause extensive destruction of the brain, usually with catastrophic results, because the pellets enter the cranial cavity bunched together, thus acting as a single projectile of large diameter and kinetic energy. Injuries from fragments present with multiple, more or less circular wounds of various depths, depending on the kinetic energy of the fragments. This review includes a conceptual temporal organization of factors that have a prognostic significance, including those related to projectile and energy transfer characteristics and their consequences.