Gun shot wounds

Background

• Bullets
  • Lead alloy
  • Full metal or partial metal jacket around lead core
  • Tip variation (pointed, flat, hollow, soft)
• General caliber classification
  • Small (.22, .25)
  • Medium (.32, .38, .357, 9mm)
  • Large (.40, .41, .44, .45, .50)
• Common shotgun gauges
  • 12-gauge = bore diameter of .729 inches
  • 20-gauge = .615 inches
• Shotgun pellets, small to large
  • Birdshot (shotshells) - many small pellets, large kill spread
  • Buckshot - fewer pellets, larger pellets
  • Slug, sabots - single large solid slug

Types

High Velocity Bullets

• Examples: M-16 or 30/06 Springfield
• Very high kinetic energy
• Little deformity when fired
• Cavitation is principle mechanism of destruction, the dissipation of energy radially away from the bullet as it travels through tissue
• Large zone of tissue injury even away from tract

Low Velocity Bullets

• Examples: .22 long rifle or .45 pistol
• Relatively low kinetic energy
• Deform from friction
• Crash injury is principle mechanism of damage given projectile tumbling and fragmentation

Shotgun

• Very high kinetic energy at close range
• Shells contain several to several hundred hundred pellets
• Spread of pellets and rapid energy transfer makes these weapons dangerous at close range

Clinical Features

• Assess for entrance and exit wound
  • Exit wound may not follow logical trajectory
  • May be absent, especially with low velocity GSWs
  • Strongly consider not documenting "entrance" vs. "exit" given medicolegal implications if not completely sure
• Missiles refer to fragments of bone or other tissue, secondary to the bullet
• Refer to specific systems for additional information
• Entrance
  • Round, punched out hole
  • Marginal abrasion or abrasion ring
  • +/- fouling (soot)
  • +/- stippling (punctate abrasions from gunpowder impact)
• Exit
  • Usually larger (except head)
  • Wound edges may be reapproximated
  • No marginal abrasion
  • Slit-like, stellate, circular
  • Irregular due to loss of kinetic energy, bullet deformation, yaw
• Range of fire
  • Contact - < 12 in, fouling/soot, muzzle stamp (tight contact)
  • Intermediate - 2.5-3.5 ft, +/- fouling, stippling
  • Distant - > 3.5 ft, marginal abrasion only
• Shotgun extrance wounds
  • Marginal abrasion, fouling, stippling
  • Plastic wad found in body in range < 5-10 ft
  • Close range < 12 inches with ~1 inch diameter single hole with fouling
  • 3 ft - round hole, scalloped edges, stippling
  • 4 ft - round hole, scalloping, satellites
  • Distant (> 10 ft) - pellet spread

Region Specific Information

• Head Trauma (Main)
• Penetrating neck trauma
• Cardiac Trauma
  • Pericardial effusion and tamponade
• Diaphragm Injury
• Abdominal Trauma
• Open Fracture
• Spinal Trauma (Main)

Workup

• ATLS/FAST/Trauma Labs
• CT Scan as needed depending on location
• X-ray if bony injury suspected
• CTA if vascular injury suspected

Management

• Trauma consult depending on location and extent of wound
• Ortho consult for bony injuries
• Neuro/OMF/ENT as needed

Prophylactic Antibiotics

• Infection after gunshot injury is a rare complication
• No prophylactic antibiotics for:
  • Soft tissue gun shot wounds
  • Non-operative fractures caused by gun shot wounds
• Give prophylactic for:
  • Intra-articular fracture (any type of gun shot wound)
  • Fractures caused by high-velocity weapons or shotguns

Disposition

• To OR if significant injuries
• Admission/Obs for less concerning injuries
• Minor injuries may be discharged
• GSW Protocol allows lower extremity wounds to be discharged from ED after 9 hours without invasive imaging if they have normal ABIs