Introduction

Penetrating abdominal trauma is seen in many countries. The most common cause is a stab or gunshot. The most common organs injured are the small bowel (50%), large bowel (40%), liver (30%), and intra-abdominal vascular (25%). When the injury is close range, there is more kinetic energy than those injuries sustained from a distance. Even though most gunshot wounds typically have a linear projection, high-energy wounds are associated with unpredictable injuries. There may also be secondary missile injuries from bone or bullet fragments. Stab wounds that penetrate the abdominal wall are difficult to assess. Occult injuries can be missed, resulting in delayed complications that can add to the morbidity.

Etiology

Penetrating trauma occurs when a foreign object pierces the skin and enters the body creating a wound. In blunt or non-penetrating trauma the skin is not necessarily broken. In penetrating trauma, the object remains in the tissue or passes through the tissues and exits the body. An injury in which an object enters the body and passes through is called a perforating injury. Perforating trauma is associated with an entrance wound and an exit wound.

Penetrating trauma suggests the object does not pass through. Penetrating trauma can be caused by violence and may result from:

• Fragments of a broken bone
• Gunshots
• Knife wounds

Penetrating trauma often causes damage to internal organs resulting in shock and infection. The severity depends on the body organs involved, the characteristics of the object, and the amount of energy transmitted. Assessment includes x-rays, CT scans, and MRI. Treatment involves surgery to repair damaged structures and remove foreign objects.

Puncture and penetration are similar.

• A puncture does not have an exit wound. It is generally due to something sharp or pointed
• This type of trauma is seen in a stabbing or when stepping on a nail.

Pathophysiology

As a projectile passes through tissue, it decelerates and transfers kinetic energy to the tissue. Increased velocity causes more damage than mass. Kinetic energy increases with the square of the velocity.

The space left by tissue that is destroyed by the penetrating object forms a cavity, and this is called permanent cavitation. In addition to the damage to the tissues they contact, medium- and high-velocity projectiles result in a secondary cavitation injury as the object enters the body, it creates a pressure wave forcing tissue out of the way, creating a cavity. The tissues move back into place, eliminating the cavity, but the cavitation has already done considerable damage.

The characteristics of the damaged tissue determine the severity of the injury: the denser the tissue, the greater the amount of energy transmitted to it.

History and Physical

Penetrating abdominal trauma is due to stabbings, ballistic injuries, and industrial accidents. These injuries may be life-threatening because abdominal organs bleed profusely. If the pancreas is injured, further injury occurs from autodigestion. Injuries of the liver often present in shock because the liver tissue has a large blood supply. The intestines are at risk of perforation with concomitant fecal matter complicating penetration.

Penetrating abdominal trauma may cause hypovolemic shock and peritonitis. Penetration may diminish bowel sounds due to bleeding, infection, and irritation, and injuries to arteries may cause bruits. Percussion reveals hyperresonance or dullness suggesting blood. The abdomen may be distended or tender indicating surgery is needed.

The standard management of penetrating abdominal trauma is a laparotomy. A greater understanding of mechanisms of injury and improved imaging has resulted in conservative operative strategies in some cases.

Evaluation

Gross assessment may be difficult as damage is often internal. The patient should be examined physically followed by ultrasound, x-ray, and/or CT scanning. Sometimes before an x-ray is performed a paper clip is taped over entry and exit wounds. 

The patient is treated with intravenous fluids and/or blood. Surgery is often required; impaled objects are secured in place so that they do not move and they should only be removed in an operating room.

Foreign bodies such as bullets may be removed, but if there is a possibility that they may cause more damage, they should be left in place. Wounds are debrided to remove tissue that cannot survive and will lead to infection.

Differential Diagnosis

• Abdominal compartment syndrome
• Hemorrhagic shock
• Trauma to pelvis, diaphragm, or genitourinary system
• Sepsis

Complications

• Open wounds
• Sepsis
• Fistulas
• Wound dehiscence
• Colostomy/ileostomy
• Short bowel syndrome