Pediatric blunt abdominal trauma: Initial evaluation and stabilization

INTRODUCTION — The evaluation of children with blunt abdominal trauma will be reviewed here. The assessment and treatment of children with specific injuries to the spleen, liver, pancreas, gastrointestinal tract or genitourinary tract are discussed separately. (See "Hollow viscus blunt abdominal trauma in children" and "Liver, spleen, and pancreas injury in children with blunt abdominal trauma" and "Blunt genitourinary trauma: Initial evaluation and management", section on 'Pediatric considerations'.)

EPIDEMIOLOGY — Children are more vulnerable to blunt abdominal injury than adults because they have (see "Trauma management: Overview of unique pediatric considerations", section on 'Abdomen'):

●Relatively compact torsos with smaller anterior-posterior diameters, which provide a smaller area over which the force of injury can be dissipated

●Larger viscera, especially liver and spleen, which extend below the costal margin

●Less overlying fat, and weaker abdominal musculature to cushion intra-abdominal structures

Among all children with blunt torso trauma, intra-abdominal injury (IAI) occurs in approximately 5 to 10 percent of patients [1]. Up to 25 percent of prepubertal children with multisystem injury who undergo additional testing have significant abdominal injury [2,3]. Motor vehicle crashes, auto-pedestrian injury, and falls are the major causes of blunt abdominal injury in children; bicycle injuries, all-terrain vehicle injuries, and child abuse also contribute [4-6]. (See "Physical child abuse: Recognition", section on 'Visceral injuries'.)

The most common structures injured in pediatric blunt abdominal trauma are solid organs, with liver and spleen being the most commonly injured, followed by kidneys. Hollow viscus injuries are the next most common form of injury, followed by injuries to the abdominal vasculature [7].

Mortality after blunt abdominal trauma is rare, occurring in <1 percent of patients with blunt torso trauma [8]. The mortality due to blunt abdominal trauma in children is directly related to the number and type of structures injured: it is less than 20 percent in isolated liver, spleen, kidney, or pancreatic trauma; increases to 20 percent if the gastrointestinal tract is involved; and increases to 50 percent if major vessels are injured [5].

STABILIZATION AND INITIAL ASSESSMENT — The initial management of children with suspected intra-abdominal injury (IAI) should proceed in a systematic fashion and adhere to the Advanced Trauma Life Support guidelines for diagnosis and treatment of immediately life-threatening injuries (table 1). (See "Trauma management: Approach to the unstable child", section on 'Initial approach'.)

Children with hemodynamic instability due to intra-abdominal bleeding should receive blood transfusion as soon as possible. Isotonic crystalloid fluid is acceptable if blood is not immediately available. Indications for emergency laparotomy include any of the following: non-response to crystalloid infusion (40 to 60 mL/kg, maximum volume: 3 L); blood transfusion (no response after 20 mL/kg [relative indication]; blood transfusion of approximately half of the patient's estimated blood volume [strong indication]).

During stabilization, children with signs of IAI and hemodynamic instability that do not respond to fluid resuscitation and blood transfusion warrant emergency laparotomy. (See 'Laparotomy' below.)

After the patient has been assessed, resuscitated, and stabilized, the patient should receive ongoing care directed by a pediatric surgeon with trauma expertise, whenever possible. Because optimal care and outcomes occur when the critically injured child is initially resuscitated and subsequently managed in a pediatric trauma center (PTC), it is preferable to provide initial care in such facilities from the outset, whenever possible, or to arrange transfer to a PTC for ongoing management. (See "Trauma management: Approach to the unstable child", section on 'Definitive care'.)

EVALUATION IN THE STABLE PATIENT — In hemodynamically stable children, evaluation for blunt intra-abdominal injury (IAI) should take place as part of the secondary survey. This evaluation may disclose other indications for observation, laboratory evaluation, imaging, or laparotomy. (See 'Approach' below and 'Radiologic evaluation' below and 'Laparotomy' below.)

History — Unlike penetrating trauma, which is usually apparent upon inspection, blunt abdominal trauma must be suspected from historical information, particularly the mechanism of injury, and careful physical examination [1,9-11].

Mechanisms of blunt injury that are associated with IAI include isolated, high-energy blows to the abdomen (eg, fall from a bicycle on to the handlebar (picture 1)) and high-risk trauma mechanisms including motor vehicle collisions, seat belt usage (picture 2), and falls from a height greater than 10 feet or two to three times the patient’s height (table 2) [1,12-14]. (See "Prevention of falls and fall-related injuries in children", section on 'Falls from height'.)

Patients who report abdominal pain after blunt torso trauma are also at significant risk of intra-abdominal injury. As an example, in a large, prospective multicenter trial of 10,176 children two years of age or older with blunt torso trauma, any reported abdominal pain was associated with a 13 percent risk of IAI compared to a 2 percent risk of IAI in patients with a Glasgow coma scale of 15 and no pain or tenderness on physical examination [15].

Physical examination — Children with blunt abdominal trauma warrant a complete physical examination as part of the secondary survey and consistent with the principles of Advanced Trauma Life Support. (See "Trauma management: Approach to the unstable child", section on 'Physical examination and management'.)

During the secondary survey, the clinician should pay close attention to signs of hemorrhagic shock such as tachycardia, narrowed pulse pressure, prolonged capillary refill time, pallor, or altered mental status. Although not definitive, these findings may indicate ongoing intra-abdominal hemorrhage. Significant intra-abdominal hemorrhage in children can be masked by their ability to maintain normal systolic blood pressure despite large volume blood loss. (See "Hypovolemic shock in children in resource-abundant settings: Initial evaluation and management", section on 'Pathophysiology'.)

Abdomen — In patients with vomiting, abdominal distension, or suspicion for significant abdominal injury, a nasogastric or, in patients with maxillofacial trauma, an orogastric tube should be placed before abdominal examination. Gastric decompression may facilitate accurate examination in these selected patients and minimize risk of aspiration of gastric contents if vomiting occurs [9].

Physical signs that indicate an increased risk of IAI include each of the following [9,15,16]:

●Ecchymoses (particularly of the umbilical or flank regions), such as in handlebar injuries (image 1)

●Abrasions

●Tire-track marks

●Seat belt sign in restrained passengers from motor vehicle collisions (see 'Seat belt sign' below)

●Abdominal tenderness

●Abdominal distension

●Peritoneal irritation (eg, abdominal wall rigidity, rebound, guarding, or pain in the left shoulder induced by palpation of the left upper quadrant [Kehr's sign])

●Absent bowel sounds indicating a prolonged ileus (greater than four hours)

In a prospective, multicenter observational study of 12,044 children, including 1868 children younger than two years of age, undergoing evaluation for blunt torso trauma the percent risk for IAI in patients with selected findings was significantly increased compared to the baseline risk of 5 percent for the 2217 patients without abdominal pain or tenderness as follows [15]:

●Peritoneal irritation present: 44 percent

●Abdominal distension present: 31 percent

●Any abdominal tenderness present: 13 percent

●Bowel sounds absent: 8 percent

Repeated, serial examinations are necessary in children with abdominal trauma because serious IAI may not be apparent upon the initial examination [8,17]. Abdominal tenderness may be especially difficult to determine in young children who are frightened and cannot clearly communicate and in older children who are uncooperative or neurologically impaired [18,19].

Abdominal injury can also be difficult to identify in children with concurrent extra-abdominal injury (eg, head trauma, thoracic trauma, or extremity fracture) or impaired neurologic status (eg, traumatic brain injury or substance use) [15,20]. Clinicians should have a lower threshold for additional studies and observation in these patients.

Seat belt sign — The seat belt sign was first described as part of a trio of findings consistent with "seat belt syndrome," which included vertebral chance fracture (image 2), abdominal wall ecchymosis (picture 2), and IAI (image 3 and image 1). Abdominal wall ecchymosis in a linear pattern across the abdomen in restrained children who are injured in a motor vehicle collision (seat belt sign) is strongly and independently associated with significant IAI, especially hollow viscus injuries [8,14]. Thus, most patients with a seat belt sign warrant definitive determination of IAI (computed tomography [CT] of the abdomen and pelvis in stable patients or laparotomy in unstable patients who do not respond to fluid resuscitation and blood transfusion). Alert patients without abdominal tenderness who have the seat belt sign still have a significant risk of IAI and, at a minimum, warrant continued observation and laboratory evaluation [8]. Abdominal and pelvic CT is often still necessary in these patients to identify or exclude IAI.

The following observational studies support the association between the seat belt sign and IAI in restrained children who are injured in motor vehicle collisions:

●In a retrospective study of a large database of almost 150,000 children, aged 4 to 15 years, who were restrained passengers, children with abdominal bruises were 232 times more likely to have IAI than those without bruising (95% CI, 76-710) [14]. Abdominal bruises had a sensitivity and specificity for IAI of 74 and 99 percent, respectively. Among patients without abdominal wall bruising, the negative predictive value for IAI was 99.9 percent. Among all patients, significant IAI was present in 0.2 percent (309 children) and abdominal bruising in 1.3 percent (1967 patients).

●In a multicenter, prospective, observational study of 1864 children injured in a motor vehicle collision who underwent definitive determination of the presence of an IAI by CT, laparotomy, or autopsy, IAIs occurred more frequently in children demonstrating a seat belt sign than those who did not (19 versus 12 percent, respectively) [8]. A greater number of hollow viscus or mesenteric injuries in children with a seat belt sign accounted for the difference in rates of IAI between the groups. The seat belt sign was independently associated with IAI after adjustment for vomiting, hypotension, altered mental status, evidence of thoracic trauma, and abdominal or costal margin pain (risk ratio [RR] 1.8, 95% CI 1.3-2.4). Among patients with normal or near-normal mental status and no abdominal tenderness, IAI occurred in 6 percent of the 194 patients with a seat belt sign and 2 percent of the 1714 patients without.

Associated injuries — Tenderness during palpation of the lower ribs may indicate rib fracture. Among 476 hospitalized children and adults with solid abdominal organ injury, lower rib fractures were associated with splenic or hepatic injury in 31 and 15 percent of cases respectively [21].

Children with abdominal trauma should have their genitalia and perineum evaluated during the secondary survey. The index of suspicion for pelvic, rectal, urethral, and vaginal injuries should be heightened in patients with lacerations, bruising, urethral bleeding, or straddle injuries. (See "Trauma management: Approach to the unstable child", section on 'Perineum' and "Straddle injuries in children: Evaluation and management", section on 'Females'.)

While digital rectal exams are not routinely helpful in the evaluation of pediatric trauma patients, they should be performed if the mechanism of injury or examination indicate possible spinal cord injury. Decreased rectal sphincter tone may indicate spinal cord injury. Additional signs of spinal cord injury include priapism, hypotension with relative bradycardia, and decreased strength and sensation [22].

Laboratory evaluation

Approach — While there is no standardized "trauma panel," the following laboratory studies are warranted in children with blunt abdominal trauma and suspected intra-abdominal injury:

●Complete blood count (CBC)

●Blood type and crossmatch

●Arterial or venous blood gas

●Serum transaminases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST])

●Serum electrolytes, creatinine, blood urea nitrogen

●Blood glucose

●Amylase and lipase

●Prothrombin time (PT), partial thromboplastin time (PTT)

●Urinalysis

Hemodynamically unstable patients – Children with hemodynamic instability due to intra-abdominal bleeding that is unresponsive to crystalloid infusion and blood transfusion require emergency laparotomy. Laboratory tests, especially a CBC and blood type crossmatch, should be obtained in a manner that does not delay operative care. Additional required studies as described above are obtained during or after surgery. (See 'Laparotomy' below.)

Hemodynamically stable patients with signs of IAI – Hemodynamically stable children in whom IAI is strongly suspected on the basis of clinical findings should undergo emergency CT of the abdomen and pelvis without waiting for laboratory results [19]. Although laboratory studies should be obtained, the CT should be obtained without waiting on the results of the laboratory tests. (See 'Physical examination' above and 'Abdominal and pelvic CT' below.)

Hemodynamically stable patients without signs of IAI – Hemodynamically stable children who are alert, cooperative, and have a normal physical examination but a concerning mechanism of injury may occasionally have IAI that can be identified by serial abdominal examination and laboratory testing. We recommend that these patients undergo the above laboratory testing. The presence of unexplained anemia, gross or microscopic hematuria (≥50 red blood cells [RBCs] per high-powered field) or elevation of serum transaminases (AST >200 international unit/L [3.33 microkatal/L] or ALT >125 international unit/L [2.08 microkatal/L]) indicates the need for abdominal and pelvic CT [18,19]. (See 'Specific tests' below and 'Abdominal and pelvic CT' below.)

Specific tests

Hemoglobin and hematocrit — In hemodynamically unstable patients, hemoglobin and hematocrit should be measured frequently. A decline in these values over time indicates profuse hemorrhage. In hemodynamically stable patients with abdominal pain or tenderness after significant blunt trauma, hemoglobin and hematocrit should be followed serially (every four to six hours until measurement is unchanged) because the initial hemoglobin and hematocrit in a patient with acute blood loss can be normal if equilibration of intravascular volume has not yet occurred. An initial hematocrit of less than 30 percent suggests severe blood loss. (See "Trauma management: Approach to the unstable child", section on 'Laboratory studies'.)

Blood type and crossmatch — Type and cross for packed RBCs permits efficient transition to type specific blood product transfusion if crystalloid fluid resuscitation does not reverse shock. The emergency clinician should order a blood type and crossmatch for any victim of significant blunt abdominal trauma in anticipation of the need for transfusion. For the patient with evidence of a potentially life-threatening intra-abdominal hemorrhage, O negative uncrossmatched packed RBCs should be given emergently. Consideration should also be given to transfusing with whole blood, if available [23]. The blood bank should be rapidly notified by phone or in person so that type-specific blood and, when necessary, other blood products (eg, FFP, platelets, rVIIa) can be made available as soon as possible. (See "Trauma management: Approach to the unstable child", section on 'Laboratory studies'.)

Urinalysis — Urinalysis is usually performed as a screening test for genitourinary and renal trauma and to assess the need for imaging. Observational studies suggest that CT of the abdomen and pelvis with intravenous (IV) contrast is only indicated in children with gross hematuria, microscopic hematuria ≥50 RBCs per high-powered field, vertical deceleration injuries (eg, falls >20 feet), and/or physical signs of renal injury (eg, flank pain or ecchymosis) [24,25]. Asymptomatic patients with microscopic hematuria and otherwise normal physical findings have major renal injuries less than 2 percent of the time and may not require imaging. These patients may be followed as an outpatient to ensure that the hematuria clears.

Hematuria is variably present in patients with serious renal injury and may be transient. Thus, the first urine sample obtained from the patient should be tested for blood.

Liver transaminases — We recommend that clinicians obtain transaminases in patients who have sustained potentially significant blunt abdominal trauma and are hemodynamically stable. We recommend that patients with elevated liver enzyme studies (AST >200 international unit/L [3.33 microkatal/L] or ALT >125 international unit/L [2.08 microkatal/L]) undergo CT of the abdomen and pelvis.

Elevation of transaminases in hemodynamically stable children with blunt abdominal trauma appears to be a sensitive and specific indicator of IAI [19,26].

●In one prospective observational study of 107 IAI in 1095 children younger than 16 years who presented to an urban Level I trauma center for management of blunt abdominal trauma, elevation of aminotransferases (AST >200 U/L [3.33 microkatal/L] or ALT >125 unit/L [2.08 microkatal/L]) was independently associated with IAI identified by radiologic imaging, laparotomy, or autopsy (odds ratio [OR] 17.4, 95% CI 9.4-32.1) [19].

●In another retrospective study of 43 hemodynamically stable children who underwent abdominal CT for blunt abdominal trauma, AST >450 international unit/L (7.50 microkatal/L) and ALT >250 international unit/L (4.17 microkatal/L) were present in 19; 17 of these had hepatic injury identified on abdominal CT scan [26]. By contrast, none of the patients with AST <450 international unit/L (7.50 microkatal/L) and ALT <250 international unit/L (4.17 microkatal/L) had evidence of hepatic injury on CT scan. Beyond these threshold levels, no correlation was found between the serum enzyme level and extent of hepatic injury visible on CT scan [26].

Pancreatic enzymes — Elevated serum amylase (>125 international unit/L [2.08 nkat/L]) may indicate IAI but is not specific for pancreatic injury [27,28]; nor is elevated amylase a sensitive indicator of CT- or laparoscopically-proven pancreatic injury [6,27-33]. Similarly, lipase is not a sensitive indicator for IAI. In one prospective study of 85 consecutive blunt abdominal trauma victims, amylase and lipase were measured serially [27]. Although one-half of the patients had elevation of one of these enzymes, only one patient had pancreatic injury documented by clinical course, operation, or autopsy. In another observational study of 83 children with blunt abdominal trauma and evidence of IAI on CT, lipase had a positive predictive value of 75 percent.

Thus, some authors conclude that amylase is of no value in the clinical management of patients with blunt abdominal injury [34], whereas others continue to recommend its measurement [6]. We usually measure serum amylase and lipase in children with significant blunt abdominal trauma to serve as a baseline measure for comparison if symptoms of abdominal pain persist after initial evaluation.

Other testing — Postmenarcheal females should undergo urine or serum pregnancy testing. A blood ethanol level and urine drug screen is warranted in adolescent patients and in children with signs of intoxication. (See "Trauma management: Approach to the unstable child", section on 'Laboratory studies'.)

Radiologic evaluation — The primary imaging modalities for the evaluation of IAI are ultrasound, specifically the focused assessment with sonography for trauma (FAST), and CT of the abdomen and pelvis.

Ultrasonography — Extended focused assessment with sonography for trauma (e-FAST) is a rapid ultrasound examination of four abdominal locations (right upper quadrant, left upper quadrant, subxiphoid region, and pelvis) performed at the bedside of the injured patient. The primary utility of this examination for the unstable trauma patient is the detection of hemopericardium and/or intraperitoneal fluid secondary to IAI. Unstable children with blunt abdominal trauma and intraperitoneal fluid on e-FAST may warrant operative intervention in lieu of CT of the abdomen and pelvis.

In a hemodynamically stable child with blunt abdominal trauma, a positive e-FAST by a trained and experienced physician indicates that IAI is likely, while a negative e-FAST should not exclude further workup for IAI because e-FAST has inadequate sensitivity and specificity, especially for solid organ or hollow viscus injury. For example, in a meta-analysis of eight prospective studies (2135 children), e-FAST examinations for IAI had a pooled sensitivity of 35 percent and specificity of 96 percent [35]. In addition, because of its poor sensitivity, the e-FAST should be interpreted in the setting of the patient's overall clinical status. (See "Trauma management: Approach to the unstable child", section on 'e-FAST (extended focused assessment with sonography for trauma)'.)

Contrast-enhanced ultrasound (CEUS) is an emerging alternative or complementary imaging modality for evaluation of pediatric trauma, particularly in low-energy blunt abdominal trauma. CEUS is more sensitive compared with baseline ultrasound and nearly as sensitive as CT in characterizing solid organ trauma [36]. A meta-analysis showed that CEUS had 98 percent sensitivity for detecting solid organ injuries [37]. CEUS can avoid the use of ionizing radiation and is particularly useful in monitoring known injuries for patients managed nonoperatively [38]. However, further study is needed to establish appropriate guidelines for pediatric trauma.

Abdominal and pelvic CT — Hemodynamically unstable patients who remain unstable after receiving fluid resuscitation and blood transfusion warrant emergency laparotomy and should not have this procedure delayed by abdominal and pelvic CT.

Abdominal and pelvic CT with IV contrast is the preferred diagnostic imaging modality to detect IAI in hemodynamically stable children who have sustained significant blunt abdominal trauma. CT is both sensitive and specific in diagnosing liver, spleen, and retroperitoneal injuries. It is, however, less sensitive in identifying hollow viscus injuries. (See "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Imaging'.)

Our approach is to perform the initial abdominal CT using IV contrast only when evaluating hemodynamically stable children with signs of IAI.

Indications — Indications for abdominal CT scan (only for use in the hemodynamically stable patient) include the following [6,9,10,19,39]:

●Inability to perform adequate abdominal examination or serial abdominal examinations (eg, head injury, altered sensorium, very young or nonverbal child, or planned general anesthesia) in a hemodynamically stable patient with history or mechanism suggestive of intra-abdominal injury

●Abdominal pain or tenderness not caused by a minor, superficial injury (eg, bruise, abrasion)

●Abdominal wall bruising (eg seat belt sign, handlebar bruising, or other bruising concerning for child abuse) (see 'Seat belt sign' above and "Physical child abuse: Recognition", section on 'Inflicted bruises')

●Positive FAST exam in a hemodynamically stable patient when there is concern for IAI

●Chest radiograph findings consistent with pneumo- or hemothorax or pulmonary contusion with decreased breath sounds or hypoxemia in patients with concerning mechanism for IAI

●Findings that suggest a significant risk for IAI in a patient with distracting injuries (eg, long bone fractures or substantial injury to the torso that warrants intervention)

●Initial serum AST >200 international unit/L or ALT >125 international unit/L

●Initial elevated serum pancreatic enzymes (greater than the upper limit of normal as defined by the performing laboratory)

●Gross hematuria or microscopic hematuria with ≥50 RBCs per high-powered field in otherwise asymptomatic patients

●Declining or unexplained hematocrit or hematocrit <30 percent

●Unclear etiology for persistent hemodynamic instability (ie, persistent tachycardia or hypotension) requiring IV crystalloid fluid boluses or blood requirements (imaging with CT versus operating room evaluation should be decided in collaboration with the trauma surgeon)

Use of contrast — We suggest that hemodynamically stable children undergoing CT of the abdomen and pelvis after blunt trauma receive only IV contrast, rather than both IV and oral contrast. In a preplanned subanalysis of a multicenter, prospective observational study of 5276 children undergoing CT with IV contrast of whom 1010 also received oral contrast, the sensitivity for identifying intra-abdominal injury was not significantly different with or without oral contrast (99 versus 98 percent, respectively) [40]. The specificity for IAI was 4 percent greater among those patients who received oral contrast (85 versus 81 percent). Trauma centers that only use IV contrast report similar detection of abdominal injuries during the initial evaluation of children with blunt abdominal trauma when compared to centers that continue to use oral and IV contrast.

In addition, oral contrast has the following practical limitations:

●Delayed time to CT [40]

●Vomiting [41] although low rates of aspiration have been documented in retrospective studies [42,43]

●Inadequate penetration and visualization of the small or large bowel which, based upon one small observational study, may occur in up to 60 percent of children [44]

In the above subanalysis, patients who received oral contrast had a significantly longer delay (median 12 minutes) in undergoing CT compared with children who received IV contrast alone. This delay in determination of intra-abdominal injury in the stable pediatric trauma patient is of great concern, especially in patients with time sensitive injuries to other parts of the body such as the head, chest, or extremities.

Initial CT alone is less sensitive in detecting injuries of the pancreas, intestinal tract, and bladder. In particular, the presence of blunt hollow viscus injury is often subtle and may not be identified on the first abdominal and pelvic CT, and recognition may require a high index of suspicion and hospital observation over time to make the diagnosis. (See "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Imaging' and "Hollow viscus blunt abdominal trauma in children", section on 'Imaging' and "Blunt genitourinary trauma: Initial evaluation and management", section on 'CT scanning'.)

Low-risk rule for intra-abdominal injury — Abdominal CT is associated with significant radiation exposure, and this imaging risk must be balanced with the likelihood of finding a clinically important IAI.

Several prediction rules have been proposed to identify children with very low risk of clinically significant IAI, but none have been validated:

●A multicenter, prospective observational study of 12,044 children with blunt torso trauma has derived clinical features that predict a very low risk of IAI requiring intervention (eg, laparotomy, angiographic embolization, blood transfusion, or hospitalization for two nights or longer) as follows [1]:

•Glasgow coma scale ≥14

•No evidence of abdominal wall trauma or seat belt sign

•No abdominal tenderness

•No complaints of abdominal pain

•No vomiting

•No thoracic wall trauma

•No decreased breath sounds

The absolute risk of IAI for the 5034 children who met all seven of these criteria was 0.1 percent. However, 23 percent of these patients underwent abdominal and pelvic CT. The six very low-risk patients who did have IAI had other features commonly associated with IAI (eg, hematuria, elevated liver enzymes, a distracting injury, or ethanol intoxication). Thus, implementation of this rule, if validated, has significant potential to reduce the number of abdominal and pelvic CTs in children. The authors note that failure to meet the very low-risk criteria derived in this study is not necessarily an indication for abdominal and pelvic CT and that further validation of these criteria are needed before widespread use can be recommended.

In a planned analysis of 3819 children from the low-risk IAI rule derivation study in whom abdominal CT was normal, the sensitivity and specificity for any IAI were 98 and 82 percent, respectively [45]. Only six patients (0.2 percent) subsequently received an acute intervention after CT. This evidence suggests that children who have negative findings of IAI on abdominal CT after blunt trauma are at low risk for IAI and may be candidates for discharge home rather than admission for observation if they meet the following criteria [45]:

•No abdominal pain

•No seat belt sign

•No concern for physical abuse

•No serious associated injuries

●In a prospective derivation study of nearly 2200 children evaluated for blunt abdominal trauma at level 1 pediatric trauma centers, patients who had none of the following criteria had a negative predictive value of 99.4 percent (prevalence of IAI: 12 percent) [46]:

•Aspartate aminotransferase >200 IU/L

•Abnormal abdominal examination

•Abnormal chest radiograph

•Complaint of abdominal pain

•Elevated pancreatic enzymes

Taken together, several clinical and laboratory findings appear to show promise for predicting a very low risk of a clinically important IAI. However, further study is needed to determine the applicability of specific components in heterogenous pediatric patients and settings as well as the ability for any clinical prediction rule to change physician behavior and improve clinical outcomes.  

Plain radiographs — Plain abdominal radiographs are not routinely employed for the diagnosis of IAI because they lack sensitivity and specificity relative to abdominal CT [9]. Pelvic radiographs are indicated in hemodynamically unstable patients or those with clinical findings suggestive of pelvic fracture. (See "Pelvic trauma: Initial evaluation and management", section on 'Plain radiograph'.)

Peritoneal lavage — Diagnostic peritoneal lavage (DPL) has largely been supplanted by FAST, CT, or laparoscopy. DPL may rarely be useful in the evaluation of a hemodynamically unstable child, particularly if he or she requires emergent surgery (eg, craniotomy), and time does not permit an abdominal CT scan and a FAST scan is indeterminant [9]. Some surgeons prefer performance of emergent laparotomy to DPL.

DPL is considered positive if [9,47]:

●More than 5 mL of gross blood are obtained

●Obvious enteric contents (eg, bile, stool) are obtained

●Extravasation of peritoneal lavage fluid from a chest tube or urinary bladder catheter occurs

●Lavage fluid contains >100,000 RBCs or >500 white blood cells (WBCs) per mm³

●The amylase concentration of peritoneal lavage effluent is elevated (>175 international unit/L [2.92 nkat/L])

Abdominal CT is performed instead of DPL in the hemodynamically stable child because DPL is less injury- and organ-specific, cannot detect retroperitoneal injury, and has potential risks, including the introduction of air or fluid into the abdomen, peritoneal irritation, and false positive results that may lead to exploratory surgery when clinical observation would be the more appropriate treatment [47].

Relative contraindications to DPL include pregnancy or previous abdominal surgery.

DEFINITIVE MANAGEMENT — Definitive management of children with intra-abdominal injury (IAI) after blunt trauma should be determined by a pediatric surgeon with trauma expertise, whenever possible. In regions in which such expertise is not available, a trauma surgeon with pediatric expertise is also acceptable. Most hemodynamically stable children with IAI can be managed nonoperatively.

Laparotomy — Indications for immediate laparotomy include supporting evidence of significant intra-abdominal injury (based upon history, physical examination, computed tomography [CT], diagnostic peritoneal lavage [DPL], or ultrasound) and [9]:

●Perforation from a hollow viscus injury demonstrated as pneumoperitoneum.

●Intra-abdominal bleeding of more than half the patient's blood volume demonstrated as persistent or recurring hemodynamic instability, despite crystalloid infusion and blood transfusion, especially when accompanied by abdominal distension. Of note, hemodynamic instability caused by a pelvic fracture frequently warrants treatment other than laparotomy. All hemodynamically unstable children warrant initiation of a predetermined massive transfusion protocol. (See "Trauma management: Approach to the unstable child", section on 'Massive transfusion protocol'.)

Relative indications for laparotomy include [4,48]:

●Increasing abdominal tenderness or peritoneal irritation

●Transfusion requirement of packed red blood cells (RBCs) or whole blood for intra-abdominal bleeding

Other indications for laparotomy vary according to the specific injury:

●Diagnosis of hollow visceral injury with perforation (see "Hollow viscus blunt abdominal trauma in children", section on 'Management')

●Solid organ injury with evidence of continued bleeding (see "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Damage-control surgery' and "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Spleen' and "Blunt genitourinary trauma: Initial evaluation and management", section on 'Disposition and definitive management')

●Pancreatic injury with major parenchymal or ductal disruption (see "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Pancreas')

Nonoperative management — Careful observation without operative intervention for hemodynamically stable children with solid organ injuries from blunt abdominal trauma, in a facility with operative capability and surgical expertise, is a standard practice that is safe and improves patient outcome and resource utilization. In addition, preservation of the spleen in children with splenic injuries avoids the infectious risks associated with splenectomy. (See "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Principles of nonoperative management'.)

In addition, whenever possible, initial care for children with blunt abdominal trauma should occur in pediatric trauma centers (PTC). When this option is not available, consultation with and transfer to a PTC for ongoing management is strongly encouraged. (See "Trauma management: Approach to the unstable child", section on 'Definitive care'.)

Characteristics of injuries that ultimately required surgery were reported in a retrospective series from seven level I pediatric trauma centers describing 1818 children with solid organ injury initially managed nonoperatively [49]. The following findings were noted:

●Surgery was subsequently required for 89 (5 percent) patients with the following injuries: kidney (3 percent), liver (3 percent), spleen (4 percent), and pancreas (18 percent).

●The reasons for failure of nonoperative management included the following: shock (33 percent), peritonitis (27 percent), persistent hemorrhage (16 percent), hollow viscus injury-related (15 percent), isolated pancreatic injury (8 percent), and ruptured diaphragm (1 percent).

●Failure of nonoperative management was significantly associated with injury severity, pancreatic injury, and multiple organ system involvement.

●Need for operative intervention was determined within 12 hours of the injury for 76 percent of patients.

Despite the proven advantages of nonoperative management for solid organ injuries from blunt abdominal trauma, observational studies document that children cared for in general hospitals are significantly more likely to undergo splenectomy than those cared for in children's hospitals [50-53]. Thus, strategies need to be created to increase compliance with guidelines for the nonoperative management of solid organ injury in children that target clinicians and other clinicians in general hospitals, where the majority of injured children receive care.

Angiographic embolization — Based upon limited evidence, angiography may be an alternative to surgery in hemodynamically unstable children with blunt liver or spleen injury and an arterial blush on CT imaging; it is not indicated in stable patients with this finding. (See "Liver, spleen, and pancreas injury in children with blunt abdominal trauma", section on 'Angiography and embolization'.)

Discharge after initial evaluation — Children who have negative findings of IAI on abdominal CT after blunt trauma are at low risk for IAI and may be candidates for discharge home rather than admission for observation if they meet the following criteria [45]:

●No abdominal pain

●No seat belt sign

●No concern for physical abuse

●No serious associated injuries

SPECIFIC INJURIES

Liver, spleen, or pancreas injury — The evaluation and management of children with liver, spleen, or pancreas injury after blunt trauma is discussed in detail separately. (See "Liver, spleen, and pancreas injury in children with blunt abdominal trauma".)

Gastrointestinal tract — The evaluation and management of hollow viscus injuries in children who sustain blunt trauma is discussed in detail separately. (See "Hollow viscus blunt abdominal trauma in children".)

Renal injury — Similar to injury to other organs, hemodynamically unstable children with renal trauma may require emergency operative intervention; hemodynamically stable children with renal trauma typically undergo nonoperative management with close observation in a pediatric intensive care unit [54].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Pediatric trauma".)

SUMMARY AND RECOMMENDATIONS

●Stabilization – Initial evaluation of pediatric trauma patients should first address life-threatening injuries that compromise airway, breathing, and circulation (table 1). Hemodynamically unstable children with suspected intra-abdominal injury (IAI) who are not responsive to intravenous (IV) crystalloid and blood transfusions during stabilization warrant emergency surgery ideally by a pediatric surgeon with trauma expertise. (See 'Stabilization and initial assessment' above and 'Laparotomy' above.)

In hemodynamically stable patients, assessment for blunt IAI should take place as part of the secondary survey. (See 'Stabilization and initial assessment' above and 'Evaluation in the stable patient' above.)

●History – Injury mechanisms associated with IAI include isolated, high-energy blows to the abdomen (eg, fall from a bicycle onto the handlebar) and high-risk trauma mechanisms including motor vehicle collisions, seat belt usage, and falls from a height greater than 10 feet (or two to three times the patient's height) (table 2). (See 'History' above.)

●Physical examination – Signs of IAI include any one of the following abdominal findings (see 'Abdomen' above and 'Associated injuries' above):

•Ecchymoses (particularly of the umbilical or flank regions)

•Abrasions, tire-track marks, or seat belt marks

•Distension, tenderness, or masses

•Signs of peritonitis such as guarding, rebound, rigid abdomen, or pain in the left shoulder induced by palpation of the left upper quadrant (Kehr sign)

•Prolonged ileus (greater than four hours)

Concurrent extra-abdominal injury such as serious head trauma, spinal cord injury, thoracic trauma, extremity fracture, substance use, or lack of cooperation may make the abdominal examination unreliable. Signs of abdominal injury are variable and may evolve over time, necessitating serial examinations. (See 'Abdomen' above.)

●Ancillary studies – The patient's condition determines the approach to laboratory evaluation and imaging (see 'Approach' above):

•Hemodynamically unstable – Hemodynamically unstable children with IAI not responsive to crystalloid infusion and blood transfusion require emergency surgery. Laboratory tests, especially a complete blood count (CBC) and blood type crossmatch, should be obtained in a manner that does not delay operative care. Additional required studies as described below for stable patients are obtained during or after surgery. (See 'Laparotomy' above and 'Hemoglobin and hematocrit' above.)

Preoperative bedside ultrasonography (extended focused assessment with sonography for trauma [e-FAST]) is useful for the rapid, early evaluation of hemodynamically unstable children with potential blunt abdominal trauma (see 'Ultrasonography' above). Abdominal and pelvic computed tomography (CT) should not delay operative care in hemodynamically unstable children with suspected IAI. (See 'Abdominal and pelvic CT' above.)

•Hemodynamically stable – Hemodynamically stable children warrant the following laboratory studies (see 'Approach' above):

-CBC

-Blood type and crossmatch

-Arterial or venous blood gas

-Serum transaminases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST])

-Serum electrolytes, creatinine, blood urea nitrogen

-Blood glucose

-Amylase and lipase

-Prothrombin time (PT) and partial thromboplastin time (PTT)

-Urinalysis

After laboratory studies are obtained in stable patients, imaging decisions are based upon the clinical suspicion for IAI and should be made in consultation with a pediatric surgeon with trauma expertise (see 'Abdominal and pelvic CT' above and 'Indications' above):

-Patients with high clinical suspicion for IAI based upon physical examination or positive e-FAST findings should undergo emergency CT of the abdomen and pelvis with IV contrast enhancement without waiting for laboratory results.

-Contrast-enhanced abdominal and pelvic CT is also indicated in patients with major trauma and an unreliable physical examination, abnormal laboratory findings (eg, elevated serum liver enzymes, gross hematuria, or elevated pancreatic enzymes), or significant or worsening abdominal pain on serial examinations, including patients with normal laboratory results but a concerning mechanism of injury. (See 'Specific tests' above.)

-Patients at very low risk of IAI should not undergo CT.

●Definitive management – Definitive management of children with IAI after blunt trauma should be determined by a pediatric surgeon with trauma expertise, whenever possible. Most hemodynamically stable children with IAI can be managed nonoperatively. (See 'Definitive management' above and 'Specific injuries' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Donna Reyes Mendez, MD who contributed to an earlier version of this topic review.