A Gunshot Wound (GSW) is the medical term for severe penetrating trauma caused by a projectile discharged from a firearm. This injury involves high-energy transfer, resulting in complex damage that extends far beyond the visible wound track. A GSW is a life-threatening emergency requiring rapid assessment and intervention by specialized trauma teams. Severity depends on the projectile’s velocity, its path through the body, and the organs affected.
The Physics of Gunshot Injury
The devastating effect of a gunshot wound is primarily determined by the transfer of kinetic energy from the moving projectile to the body’s tissues. Velocity is far more influential than mass in determining damage potential, since velocity is squared in the kinetic energy calculation. Doubling a bullet’s velocity, for instance, quadruples its potential to cause damage.
Projectiles are categorized by their velocity, which relates directly to the mechanism of injury. High-velocity rounds, such as those from military or hunting rifles, typically travel faster than 2,000 feet per second. Low-velocity rounds, usually from common handguns, move slower than 2,000 feet per second, limiting the extent of their destructive effects.
As the projectile passes through tissue, it generates two distinct types of cavities. The permanent cavity is the track of crushed and lacerated tissue directly in the bullet’s path, proportional to the projectile’s size. The second, and often more destructive, is the temporary cavity, created by a massive shockwave radiating outward from the bullet track.
Temporary cavitation involves the radial stretching of surrounding tissue to many times the projectile’s diameter, lasting only a few milliseconds. For high-velocity projectiles, this creates immense pressure and shear forces. Tissues with low elasticity, such as the brain, liver, and spleen, are particularly susceptible to this stretching and tearing, leading to catastrophic injury.
How Gunshot Wounds Are Classified
Gunshot wounds are classified based on the projectile’s trajectory through the body, which guides both forensic documentation and initial medical assessment. A penetrating wound occurs when the projectile enters the body but does not exit, remaining lodged within the tissues. Only a single entrance wound is visible, and the projectile’s entire remaining kinetic energy is dissipated into the body.
A perforating wound involves the projectile passing completely through the body, resulting in both an entrance and an exit wound. The projectile only transfers a fraction of its total kinetic energy, as some energy is retained upon exiting. The appearance of these wounds provides important clues about the mechanism of injury.
The entry wound is typically smaller and neat, with a circular or elliptical defect in the skin. This wound may be surrounded by an abrasion collar, caused by the projectile pressing against the skin as it enters. Exit wounds are generally larger, more irregular, and often gaping due to the explosive release of energy and the tumbling or fragmentation of the bullet.
Clinical Management of Trauma
The initial medical response for a patient with a gunshot wound follows the standardized trauma protocol known as the ABCDE approach. This systematic process prioritizes the assessment and treatment of immediate life threats.
- Airway management with cervical spine protection ensures the patient can breathe effectively.
- Breathing addresses identifying and treating conditions like a tension pneumothorax.
- Circulation focuses on controlling severe hemorrhage and managing hypovolemic shock, often requiring immediate blood product or intravenous fluid resuscitation.
- Disability assessment involves a brief neurological examination.
- Exposure requires completely undressing the patient to search for all potential injuries, including entry and exit wounds.
Following the primary survey, rapid imaging is performed, which often includes plain X-rays to locate retained projectiles or fragments and a Focused Assessment with Sonography for Trauma (FAST) exam. Unstable patients—those with dangerously low blood pressure—often bypass extensive imaging and proceed immediately to the operating room for surgical exploration to control internal bleeding. Stable patients may undergo a comprehensive Computed Tomography (CT) scan to map the projectile’s trajectory and identify subtle internal organ damage. The ultimate goal is to control hemorrhage, repair damaged organs, and prevent life-threatening complications like infection or multi-system organ failure.