• Clinical science

Penetrating trauma

Abstract

Penetrating trauma is an injury caused by a foreign object piercing the skin, which damages the underlying tissues and results in an open wound. The most common causes of such trauma are gunshots and stab wounds. Clinical features differ depending on the injured parts of the body and the shape and size of the penetrating object. Diagnosis is established based on history and imaging studies (X-rays, CT/MRI). Management usually involves supportive measures (hemostasis, blood transfusion, respiratory support), and surgical repair of damaged structures and/or removal of foreign bodies.

General information

Gunshot injuries

  • Epidemiology
    • Mortality due to gunshot injuries in the USA is 10.2 per 100,000 cases
    • More suicidal firearm-related deaths than homicidal deaths (2:1)
  • Mechanisms of injury
    • Medium-velocity (1000–2000 feet/sec in handguns and air-powered pellet guns), or high-velocity (> 2000 feet/sec in rifles and assault guns) injuries
    • Damage also caused to structures adjacent to the path of the bullet
    • Dense organs (e.g., liver, spleen) undergo more damage because they absorb more energy, resulting in greater injury.

Other penetrating injuries

  • Epidemiology
    • One of the most common forms of penetrating trauma globally
    • Mortality due to stab wounds 0.51 per 100,000 cases
  • Mechanism of injury
    • Usually caused by a sharp, impaling object (e.g., knife, ice pick, broken bottle)
    • Low-velocity injuries with penetration < 1000 feet/sec
    • Hemorrhage and infection are the most significant mechanisms responsible for morbidity and mortality.

References:[1][2]

Penetrating abdominal trauma

Etiology

Clinical features

  • Visible entry wounds
    • Sites of injury
      • Gunshot wounds; : most commonly small bowel; , colon; , and liver
      • Stab wounds; : most commonly liver; , small bowel; , and diaphragm
  • Signs of abdominal bleeding: hypotension, tachycardia; , cyanosis, anxiety, flank discoloration; , shock
  • Pain, abdominal rigidity, and distention
  • Abdominal compartment syndrome

Any wound located anteriorly between the nipple line (T4) and the groin creases, and posteriorly between T4 and the curves of the iliac crests is considered a potential penetrating abdominal injury!

Approach to penetrating abdominal trauma

  1. History: : details such as number of shots; heard, amount of blood loss at the scene of injury, and position of patient when shot or stabbed
  2. Preliminary assessment and care
    • Prehospital and hospital trauma care
    • Resuscitative and stabilization procedures; (e.g., rapid transfusions; , CPR) indicated if the patient is hemodynamically unstable
    • Tetanus prophylaxis
    • Broad spectrum antibiotic prophylaxis
    • Analgesics, anxiolytics
  3. Surgical management
    • Emergency exploratory laparotomy indicated in
      • Evisceration
      • Signs of peritonitis
      • Hemodynamic instability
      • Bleeding detected in nasal tube or rectal examination
      • Penetrating object still in situ (risk of precipitous hemorrhage on removal)
      • Free air under the diaphragm
    • Assess for peritoneal or retroperitoneal penetration and intra-abdominal bleeding
  4. Conservative management
    • Indications: surgical treatment not required
    • Measures
      • Close monitoring of vital signs
      • Serial physical examinations (SPE)
      • Blood analysis to monitor hemodynamic state

In cases of gunshot wounds, an entry wound in almost any part of the body can result in a penetrating abdominal injury, depending on the path the bullet may have taken through the body. This makes a comprehensive clinical and imaging-based assessment vital!

Patients without evidence of peritonitis, evisceration, and hemodynamic instability may undergo CT prior to surgical intervention!

Penetrating objects often tamponade the wound and should be removed only in a setting where definitive care is possible!

References:[3][4][5][6]

Penetrating chest trauma

Etiology

  • Gunshot wounds
  • Stabbing

Possible injuries

Clinical features

Approach to penetrating chest trauma

  1. Preliminary assessment and care: See “Preliminary assessment and care” in approach to penetrating abdominal trauma above.
  2. Emergency procedures
    • Needle decompression or a tube thoracostomy for tension pneumothorax
    • Placement of an occlusive dressing, taped on three sides, for a sucking chest wound
    • Emergency thoracotomy indicated in
      • Cardiac tamponade
      • Hemodynamically unstable patient
      • Cardiac arrest that occurred at, or after, presentation
      • Unstable patient and/or penetrating object still in-situ
  3. Assessment of injury cause and severity
    • Ultrasound (Extended Focused Assessment with Sonography in Trauma, EFAST)
    • Chest x-ray; and/or CT if patient is stable
    • Others: echocardiography, endoscopy, bronchoscopy, angiography
  4. Further management
    • Close monitoring of vital signs
    • Continual reassessment of the primary survey
    • Appropriate surgical repair after stabilization of vitals

Consider concomitant intra-abdominal injuries in cases of injury either below the nipples or the inferior scapular angle!

Any knife or similar tool used to cause a stab wound must remain in situ until intraoperative removal is possible

References:[7][8]

Other types of penetrating injury

Penetrating neck trauma

  • Etiology:
    • Stab injuries: low velocity injuries by any sharp impaling objects (knives, pens, broken glass, etc.)
    • Ballistic injuries: gunshots, missiles (shrapnel, darts, projectiles, etc.)
  • Zones of the neck:
  • Clinical features: features of injuries to the neck can be divided into
  • Approach to penetrating neck trauma
    1. Preliminary assessment and care: See “Preliminary assessment and care” in approach to penetrating abdominal trauma above.
    2. In case of presence of hard signs:
    3. Further management
      • Determine injury extent: CT angiography (best initial test), esophagram, panendoscopy
      • Gunshot wound: conservative or surgical management based on injury extent
        • Gunshot wounds to zone III: diagnosis is made by CT angiography
        • Gunshot wounds to zone I and II: CT angiography, esophagogram, and panendoscopy
      • Stab wounds
        • Patients with no signs of severe vascular or organ injury, can be safely observed

Penetrating trauma to the extremities

  • Etiology:
    • Ballistic injuries (most commonly in a military setting; gunshots, shrapnel, projectiles)
    • Stab injuries (due to sharp objects like knives, vehicular parts in road traffic accidents, rods, etc.)
  • Clinical features: presentation depends on possible underlying injuries
  • Management:
    • The approach is based on anatomic location and whether major vessel injury is suspected
      • No major vessels in the vicinity of the tract of the penetrating object: conservative management
      • Stable patients with a penetration tract in the vicinity of major vessels and local signs (pain/tenderness), but no systemic signs of hypovolemia, should undergo further diagnostic testing:
        • Plain x-ray; : evaluate extent of bony injury
        • Contrast CT angiography: evaluate vascular injury
        • Doppler ultrasonographic evaluation: evaluate vascular injury in cases with poor renal function, in which contrast CT is contraindicated
      • Patients exhibiting 'hard signs' of arterial injury: urgent surgical exploration, hemorrhage control, and repair
      • In case of combined injury to arteries, nerves and bones: start with stabilization of bone (fracture reduction etc.) → vascular repairnerve repairfasciotomy may be needed to relieve the pressure and prevent tissue necrosis

References:[9][10][11][12][13][14][15]

Diaphragmatic rupture

  • Etiology: penetrating injuries (65%), blunt trauma (35%)
  • Clinical features
    • Often initially asymptomatic
    • Chest/abdominal wall bruises
    • In case of herniation of abdominal organs into the chest
      • Decreased breath sounds; , bowel sounds in the thorax, respiratory distress
      • Signs of bowel obstruction
  • Diagnostics
    • Chest x-ray
      • Disturbed contour of the hemidiaphragm
      • Displaced abdominal organs; (esp. stomach and bowel segments): hourglass sign
      • Possible mediastinal shift
      • Nasogastric tube visible above the left hemidiaphragm
    • Ultrasound FAST: rapidly detect large tears or herniation
    • CT scan to confirm the diagnosis
  • Complications: diaphragm paralysis
  • Treatment: most patients require surgery

References:[16][17][18][19]

Hemothorax

A hemothorax, however small, must always be drained because blood in the pleural cavity will clot if not evacuated, resulting in a trapped lung or an empyema

References:[20][21][22][23][24]

Forensics related to gunshot injuries

Entrance vs exit wounds

Entrance wound Exit wound

Wound size

  • Larger than entry wound

Wound margins

  • Not adaptable
  • Adaptable

Bullet wipe

  • Often present
  • May be covered by blood
  • None present

Skin tags

  • Protruding into the wound
  • Extruding
Infiltration of textile fibers
  • Textile fibers and other foreign matter in the wound track near the entrance
  • None present

Abrasion rim/contusion

  • Present
  • None present

Muzzle to target distance

Contact range Near contact/intermediate range Distant range
Definition
  • Muzzle held against the body
  • Muzzle to target distance < 40 in (approx. 1 m)
  • Muzzle to target distance < 40 in (approx. 1 m)
Characteristics
  • Soot ring
    • Depending on various factors such as caliber, type of powder, and distance (> 12 in, 30 cm), gunshot residue may not be present.
  • Powder tattooing
  • Bullet wipe on skin or clothing

Gunshot residue

  • Upon discharge of a firearm, burnt and unburned particles of powder, cartridge primer, and other materials present in the barrel are propelled out of the firearm along with the projectile and travel through the air across short distances.
Description Cause Offers clues for:

Soot and searing

  • Location: on the skin and in the wound cavity
  • Characteristics
    • Dark gray soot residue on the skin and in the wound track and cavity
    • Searing around and in the wound
    • Cherry-red hue of muscle tissue surrounding the wound due to carbon monoxide from the discharge gas forming carboxyhemoglobin and carboxymyoglobin
In contact and near-contact wounds, the soot and powder follows the bullet into the wound rather than dispersing in the air or settling around the entry wound. Searing occurs in and around the wound from the fire and hot gasses exiting the muzzle. Near contact wounds
Soot
  • Location: surrounding the entry wound on skin or clothing
  • Characteristics
    • Flared, gray, sooty ring
    • May flare several inches beyond entry wound
Soot and powder that is propelled through the air upon discharge Near-contact/intermediate-range wounds
Bullet wipe
  • Location: on skin and clothing surrounding the entry wound
  • Characteristics
    • Clearly demarcated, dark gray margins surrounding the wound/holes in clothing
Gunshot residue adheres to the projectile and is “wiped” off when it penetrates skin or clothing.

Does not provide clues regarding target distance

Powder tattooing
  • Location: on the skin surrounding the entry wound
  • Characteristics
    • Punctate lesions surrounding the entry wound
From the impact of burned and unburned powder grains on the skin
  • Near contact wounds
  • Direction of fire

Self-inflicted gunshot injury vs gunshot by another person

Clues that wound may have been self-inflicted (suicide or accident) Clues that wound may not have been self-inflicted (accident or homicide)
Entry wounds
  • Single entry wound
  • Exposed entry wound
  • Right temple → right-handed person
  • Left temple → left-handed person
  • Multiple entry wounds possible
Distance
  • Any muzzle to target distance
Situation of weapon (uncertain)
  • Weapon near the casualty

Up to 25% of suicide casualties maintain hold of the weapon.

  • Casualty holding the weapon

  • No weapon at the scene

Gunshot residue
  • Gunshot residue and blood (from “back splatter”) on hands of casualty
  • No gunshot residue or blood on hands of casualty

Special forms of projectile injury

  • Low-velocity projectile: ricochet
  • Medium-velocity projectile: Ringel-Konturschuss
  • Medium-velocity projectile: retained projectile
  • High-velocity projectile: Krönlein shot