**1. Introduction**

Abdominal trauma (AT) accounts for the majority of abdominal injuries in the pediatric population. AT can be either blunt or penetrating. Blunt abdominal trauma involves compression, crushing, or deceleration forces being exerted on the abdominal cavity. In children, the spleen and liver are most commonly injured followed by the kidneys [1]. Motor vehicle-related injuries, seat belts, bicycle handlebars, or an elbow, foot, or knee during sports, child abuse are the most common causes of blunt force to the fragile abdomen of a child. Blunt abdominal trauma is the second leading cause of abusive trauma mortality [2–4]. Two-thirds of victims are male [2, 5]. Unintentional injury is the leading cause of death in children ages 1–19 years. Traumatic abdominal injuries are more common than traumatic thoracic injuries but are less associated with death. The abdomen is the most common site of unrecognized fatal injury in pediatric patients [2, 5–7].

Mortality in pediatric trauma has trimodal distribution, 50% of the victims die at the scene either from TBI or hemorrhage, 30% die within the first few hours ("golden hour"), the rest of the patients die due to inadequate resuscitation, management, sepsis, and multiorgan failure in days to weeks after initial injury, which is preventable by rapid identification and early aggressive treatment of the cause [8].

## **2. Discussion**

There are major anatomical and physical differences that cause pediatric patients to be at greater risk for intra-abdominal injuries than adults. Children have thin, compliant, and flexible abdomen walls and this structure does not effectively protect the corresponding viscera [9]. Relatively larger body surface area increases the risk of hypothermia and insensible losses and hides shock well. They have a smaller circulating blood volume, and even if they lose more than 25% of their blood volume, there may be no change in their blood pressure [7–12]. Their relatively compact torso and smaller anteroposterior diameter make the distribution of the traumatic forces possible over a smaller body mass.

The ribs are more pliable, and this causes severe intrathoracic pathology to occur without visible injury or rib fractures. Larger abdominal organs in children result in an increased risk of direct injury. Insulation and protection are less due to less abdominal fat and musculature. The liver and spleen are less protected by the rib cage in infants and toddlers, so, they are more prone to direct injury. The liver has less fibrous stroma than adults, which makes it more susceptible to lacerations and bleeding. Spleen has a thicker capsule which allows it to contain bleeding better than adults and may contribute to better success with nonoperative management. The bladder is an abdominal rather than a pelvic organ in young children. Renal injury is more likely in children because kidneys are proportionally larger, with less perinephric fat for protection [9, 13].

Physical examination should be done meticulously, as well as with a detailed history of trauma if possible. If physical examination reveals the presence of shoulder or lap belt marks on the abdomen, this should alert the physician of trauma to the internal organs. The pliant lower ribs can transmit the force of trauma to the underlying liver, spleen, and kidneys. The most common injuries are to renal, hepatic, bowel, and splenic structures. The massive blood loss may remain concealed or tamponaded in abdominal injuries until the clot is removed [14–21].

The physical examination should be carried out in the presence of the parents or caregivers, a familiar face with the child, since he may be frightened and the examination of the abdomen may be too difficult. Crying causes air swallowing, subsequently distension, and tenderness of the abdomen, which may complicate the clinical examination. Distension of the urinary bladder carries the same difficulty. If there is no facial trauma, decompression of the stomach with a nasogastric tube, if there is facial trauma, with an orogastric tube may be helpful. If there is no suspected urethral injury, decompression of the urinary bladder would help. It should be kept in mind that hard manipulation and extreme movements, and positioning of the victim may cause further trauma or decompensation **Figure 1** [22].

Blunt abdominal trauma (BAT) accounts for most trauma in children. Focused abdominal sonography for trauma (FAST) has recently become a useful and practical part of the initial trauma evaluation. It can be performed in a short time, noninvasive, portable, and can also be performed during resuscitation. Free fluid in Morrison's pouch, the pelvis, the peri-splenic region, and the pericardium should be sought during FAST examination. FAST is extremely sensitive to peritoneal fluid and hemoperitoneum, whereas ultrasonography may miss specific visceral injury (liver, spleen, and bowel injury). Although the focused assessment with sonography in trauma (FAST) is considered standard of care in the evaluation of adults with traumatic injuries, there is limited evidence to support its use as an isolated evaluation tool for intra-abdominal injury related to BAT in children. Although a positive FAST examination could obviate the need for a computed tomography scan before

#### **Figure 1.**

*Risk of IAA-intervention\* following pediatric abdominal blunt trauma. \*IAI-intervention: traumatic laparotomy, angiographic embolization, blood transfusion for abdominal hemorrhage, or intravenous fluids >2 nights for pancreatic/gastrointestinal injury. IAI, intra-abdominal injury; BAT, blunt abdominal trauma.*

#### **Figure 2.**

*Pediatric abdominal trauma evaluation. Abd, abdomen; CT, computed tomography; FAST, Focal Assessment with Sonography in Trauma; GCS, Glasgow Coma Scale; IAI, intraabdominal injury requiring intervention; PO, oral; UA, urinalysis. Data from [23, 24].*

#### **Figure 3.**

*Components of the FAST examination. Evaluation of hemoperitoneum using a single versus multiple view ultrasonographic examination [18].*

operating room evaluation in a hemodynamically unstable patient, a negative FAST examination cannot exclude intra-abdominal injury related to BAT in isolation **Figure 2** [25]. Brenkert et al. review the evaluation of BAT in children, describe the evaluation for free intraperitoneal fluid and pericardial fluid using the FAST examination, and discuss the limitations of the FAST examination in pediatric patients **Figure 3** [18, 24]. Since FAST has modest sensitivity for hemoperitoneum and intraabdominal injury (IAI) in the pediatric trauma patient, patients with concern for undiagnosed IAI, including bowel injury, may be considered for hospital admission and serial abdominal exams without an increased risk of complications, if an exploratory laparotomy is not performed emergently [26–30]. In another study by Quan et al.*,* it was concluded that caution is needed in applying a single initial FAST to patients with minor abdominal trauma or with suspected injuries to organs other than the spleen or bladder [27].

Abdomino-pelvic CT scanning for blunt abdominal trauma has a sensitivity of 96%, a specificity of 98%, and an accuracy of 97%. CT is organ-specific, allowing the identification and grading of injured organs and the quantification of intraperitoneal fluid or blood. This allows for the non-operative management of stable patients, thereby reducing the rate of non-therapeutic laparotomy. If available, CT is the preferred diagnostic test [31–33].

Prompt laparotomy is indicated if the child is unstable and the diagnostic test shows free blood in the abdomen, or there is a rupture of a hollow viscous. Injury to the liver, spleen, and kidneys can be managed conservatively; however, close supervision is necessary [7–11].

#### *Pediatric Abdominal Trauma DOI: http://dx.doi.org/10.5772/intechopen.108677*

An often missed entity is abdominal compartment syndrome (ACS). This is a condition in which increased pressure in the anatomic space results in organ dysfunction. Undetected increases in intra-abdominal pressure (IAP) can be life-threatening. ACS is defined by IAP > 20 mmHg (with or without an abdominal perfusion pressure < 60 mmHg) with a minimum of three standardized measurements taken 4–6 hours apart plus at least one new end-organ failure. Injury to the pelvis is associated with pelvic fractures and concealed hemorrhage. Blood at the urethral meatus is strongly suggestive of urethral injury.
