Excerpt from Abdominal Trauma, Blunt


Synonyms, Key Words, and Related Terms: intra-abdominal trauma, intra-abdominal injury, blunt abdominal injury, motor vehicle collision, motor vehicle accident, MVA, blunt trauma

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Background: Blunt abdominal trauma is a leading cause of morbidity and mortality among all age groups. Identification of serious intra-abdominal pathology is often challenging. Many injuries may not manifest during the initial assessment and treatment period. Mechanisms of injury often result in other associated injuries that may divert the physician's attention from potentially life-threatening intra-abdominal pathology.

Pathophysiology: Injury to intra-abdominal structures can be classified into 2 primary mechanisms of injury–compression forces and deceleration forces.

Compression or concussive forces may result from direct blows or external compression against a fixed object (eg, lap belt, spinal column). Most commonly, these crushing forces cause tears and subcapsular hematomas to the solid viscera. These forces also may deform hollow organs and transiently increase intraluminal pressure, resulting in rupture. This transient pressure increase is a common mechanism of blunt trauma to the small bowel.

Deceleration forces cause stretching and linear shearing between relatively fixed and free objects. These longitudinal shearing forces tend to rupture supporting structures at the junction between free and fixed segments. Classic deceleration injuries include hepatic tear along the ligamentum teres and intimal injuries to the renal arteries. As bowel loops travel from their mesenteric attachments, thrombosis and mesenteric tears, with resultant splanchnic vessel injuries, can result.

The liver and spleen seem the most frequently injured organs, although reports vary. Small and large intestines are the next most injured organs, respectively. Recent studies show an increased number of hepatic injuries, perhaps reflecting increased use of CT scanning and concomitant identification of more injuries.

Frequency:

  • In the US: True frequency is unknown. Data collected from trauma centers reflect patients who are transported to or seek care at these centers. These data may not reflect patients presenting to other facilities. Incidence of out-of-hospital deaths is unknown.

    • One review from the National Pediatric Trauma Registry by Cooper et al reported that 8% of patients (total=25,310) had abdominal injuries. Eighty-three percent of those injuries were from blunt mechanisms. Automobile-related injuries accounted for 59% of those injuries.

    • Similar reviews from adult trauma databases reflect that blunt trauma is the leading cause of intra-abdominal injury and that motor vehicle collisions are the leading mode of injury. Blunt injuries account for approximately two thirds of all injuries.

    • Hollow viscus trauma is more frequent in the presence of an associated, severe, solid organ injury, particularly to the pancreas. Approximately two thirds of patients with hollow viscus trauma are injured in motor vehicle collisions.
  • Internationally: Data from the World Health Organization indicate that falls from heights of less than 5 meters are the leading cause of injury, and automobile crashes are the next most frequent cause. These data reflect all injuries, not just blunt injuries to the abdomen.

    • A review from Singapore described trauma as the leading cause of death in those aged 1-44 years. Traffic accidents, stab wounds, and falls from heights were the leading modes of injury. Blunt abdominal trauma accounted for 79% of cases.

    • A similar paper from India reported that blunt abdominal trauma is more frequent in males aged 21-30 years; the majority of patients were injured in automobile accidents.

    • A German study indicated that of patients with vertical deceleration injuries (ie, falls from heights), only 5.9% had blunt abdominal injuries.

Mortality/Morbidity: