Pediatric Abdominal Trauma

Abstract

Pediatric patients are more prone to trauma than adults. Trauma is one of the most common causes of death in children. Their small and fragile bodies, big organs relative to their bodies, are the major causes of injury in children. Their body surface area is relatively larger than adults, which makes them vulnerable to trauma. A higher percentage of the children admitted to emergency departments need the help of anesthesiologists in the management of airway, resuscitation, mechanical ventilation, maintenance of hemodynamic stability, transfusion, management of coagulopathy, hypothermia, pain, and monitorization. Serious abdominal trauma is seen in 5–10% of multiple traumas and 25% of blunt abdominal trauma in children. Despite improvements in emergency diagnostics and evaluation, controversy still exists regarding the optimal assessment and management of pediatric trauma patients with abdominal trauma. It can be difficult to accurately describe the major abdominal traumas and symptoms that occur in children. The most important factor in accurately detecting injuries that may occur due to abdominal trauma in this age group is high suspicion. Creating a targeted treatment strategy by understanding the mechanism of injury with a detailed and careful history and physical examination may be the basic step in saving life in these patients. This chapter is aimed to discuss the management of abdominal trauma in pediatric patients.

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, 3, 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, 6, 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, 8, 9, 10, 11, 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, 15, 16, 17, 18, 19, 20, 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].

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.

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, non-invasive, 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 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, 27, 28, 29, 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].

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].

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, 32, 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, 8, 9, 10, 11].

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.

3. Specific injuries

3.1 Liver

It is usually associated with other abdominal or extra-abdominal injuries and is most commonly associated with spleen injuries. Since the posterior right lobe is fixed by the coronary ligaments, most injuries occur in this part.

Although liver injuries require aggressive resuscitation and close observation, they often require surgical intervention, which is done based on adult protocols. The greatest challenge in the management of liver injuries is their timely identification and the correct timing of aggressive resuscitation and laparotomy. Surgery should be considered in unstable patients, and it should be performed in experienced centers since liver injuries in the pediatric age group can be difficult to manage and have high morbidity and mortality.

Complications consisting of hemobilia, intrahepatic duct rupture and accompanying biliary fistula, bilemia, intrahepatic hematoma, vascular outflow obstruction, and gallstones can be seen in the early or late period. The prognosis is generally good if treated early.

The grading of liver injury performed by the American Association for the Surgery of Trauma (AAST) is given in Table 1 [20].

Grade 1	Subcapsular hematoma less than 1 cm in maximal thickness, capsular avulsion, superficial parenchymal laceration less than 1 cm deep, and isolated periportal blood tracking
Grade 2	Parenchymal laceration 1–3 cm deep and parenchymal/subcapsular hematomas 1–3 cm thick
Grade 3	Parenchymal laceration more than 3 cm deep and parenchymal or subcapsular hematoma more than 3 cm in diameter
Grade 4	Parenchymal/subcapsular hematoma more than 10 cm in diameter, lobar destruction, or devascularization
Grade 5	Global destruction or devascularization of the liver
Grade 6	Hepatic avulsion (CT scan grade not AAST grade)

Table 1.

Criteria for staging liver trauma based on the American Association for the Surgery of Trauma (AAST) liver injury scale.

Even if stability is ensured, the patient should be followed closely for late complications, especially bleeding that may occur in the late period, and CT imaging should be performed. Especially in patients with ongoing abdominal pain, care should be taken in terms of bleeding and long bed rest should be provided if necessary [8, 9, 10, 11].

3.2 Spleen

Another organ frequently injured in blunt trauma is the spleen which is also seen quite frequently with other organ injuries. Because it is smaller than other organs, it may show varying degrees of fragmentation and may be associated with intraparenchymal or subcapsular hematoma. However, unlike hepatic injury, intraperitoneal bleeding may not always be seen. If there is no rupture in the splenic cilium, a retroperitoneal hematoma extending into the anterior pararenal space may be seen. Bed rest should be given to patients with splenic injury until the pain subsides. In clinically stable patients, it may not be necessary to repeat the ultrasound [9, 10, 11].

Bleeding seen in spleen injuries can often stop spontaneously without the need for surgery. Splapsule, the hemoperitoneum may not be seen. If there is an injury extending to the henic clefts can be confused with splenic tears and may be misdiagnosed after splenic injuries.

However, splenic clefts can be easily distinguished from tears by their smooth contours and the absence of hematoma or fluid around them [24].

The grading of spleen injury performed by the American Association for the Surgery of Trauma (AAST) is given in Table 2 [20].

Grade 1	Subcapsular hematoma of less than 10% of surface area or capsular tear of less than 1 cm in depth
Grade 2	Subcapsular hematoma of 10–50% of surface area, intraparenchymal hematoma of less than 5 cm in diameter, or laceration of 1–3 cm in depth and not involving trabecular vessels pediatric blunt abdominal trauma
Grade 3	Subcapsular hematoma of more than 50% of surface area or expanding and ruptured subcapsular or parenchymal hematoma, intraparenchymal hematoma of more than 5 cm or expanding, or laceration of more than 3 cm in depth or involving trabecular vessels
Grade 4	Laceration involving segmental or hilar vessels with devascularization of more than 25% of the spleen
Grade 5	Shattered spleen or hilar vascular injury

Table 2.

Criteria for staging splenic trauma based on the AAST splenic injury scale.

3.3 Kidney

Kidney injury, which is the third most common organ injury after blunt trauma in children, may be complicated by subcapsular or perinephric hematoma that can be distinguished by CT [32].

Renal parenchymal damage can be seen, as well as vascular and collecting system damage. The injured kidney appears larger than the other kidney on CT due to edema. Early diagnosis can be made easily by imaging with ultrasound, but patients may require contrast-enhanced CT. If there is ongoing bleeding despite resuscitation treatments, laparotomy may be required, which may result in nephrectomy [30, 31, 32].

Ongoing hematuria may be seen due to AV fistula. Patients with serious injuries should be followed up with repeat ultrasound and dimercaptosuccinic acid (DMSA) scanning [7, 8, 9, 10, 11].

3.4 Pancreas

While pancreatic injury alone is rare in children, it can usually be seen together with other organ injuries. If the pancreas is small and has little surrounding fat, it can mask signs of injury. Unexplained peripancreatic fluid seen on CT is the best indicator of pancreatic damage. Fluid collected in the anterior pararenal space may cause dissection between the pancreas and the splenic vein. At the same time, trauma can cause pancreatitis in children [20, 21, 22, 23, 24, 25, 34].

It may cause peripancreatic fluid collection that transforms into a pancreatic pseudocyst or resolves spontaneously after pancreatic injury.

Initial serum amylase level does not correlate with the severity of the pancreatic injury.

There is no indication of emergency laparotomy in pancreatic injuries. Pain, nausea, and vomiting should be treated with a conservative approach, oral intake should be stopped until symptoms improve, and a CT scan should be performed in severe traumas [20, 21, 22].

3.5 Intestine

Intestinal injury, which is rare in children, is usually associated with mesenteric injury. It is mostly seen in cases where seat belts are not worn after traffic accidents [7, 8, 9, 10, 11].

Diagnosis is often difficult and delayed due to the late onset or absence of symptoms, and often a CT scan may be required. Free air on CT supports the diagnosis. If there is no significant free air in the radiographs, it may not be possible to diagnose perforation in blunt abdominal traumas. Initially, localized tenderness may worsen within 6–10 hours, and peritonitis or obstruction may develop during this time. In contrast to CT, it may be possible to diagnose enteric deterioration earlier with repeated physical examinations and serial examinations. If perforation is detected, laparotomy should be performed in the early period [20, 21, 22].

Chemical peritonitis due to perforations of the proximal gastrointestinal tract is painful and can be diagnosed early. However, since perforations occurring in the distal part of the intestine have a neutral pH and a lower bacterial load, they may be asymptomatic initially, while the onset of symptoms may be delayed, and the diagnosis due to abdominal peritonitis or sepsis may be delayed up to 24 hours, which causes a serious increase in mortality and morbidity [18, 19, 20, 21].

Diagnosis of duodenum perforations is difficult as in other intestinal parts. The presence of extraluminal air and fluid and extravasation of oral contrast should lead to suspicion of perforation [19, 20, 21, 22].

Intramural hematoma due to partial tear, most commonly seen in the duodenum; or rupture, most commonly located in the jejunum. Unexplained peritoneal fluid on CT is the most common finding after bowel rupture and may be the only finding [18, 19, 20].

In addition, thickening of the intestinal wall, mesentery damage, and chemical irritation may also occur. If there is intraperitoneal gas, an emergency laparotomy should be performed [20].

3.6 Bowel

Another organ that can be damaged in abdominal trauma is the intestines. In a possible trauma, all intestines should be evaluated from the esophagus to the rectum. Serious infections may occur due to contamination of the abdominal cavity in intestinal traumas. This is because large bowel traumas are detected later than small bowel injuries due to their retroperitoneal location. However, in pediatric patients, complete recovery can often be achieved with primary treatment without fecal contamination [26, 27, 28, 29, 30].

Perforations occurring in the rectosigmoid region may cause contamination of the abdominal cavity. Because of its retroperitoneal nature, colonic injuries often cannot be diagnosed early, resulting in fecal contamination. However, colonic injuries in pediatric patients can often be repaired with the primary repair without significant fecal contamination, except for diversions [28, 29, 30].

3.7 Bladder

Bladder injury, which is rare in children, can be intraperitoneal or extraperitoneal. It is accompanied by bruising in the suprapubic region. After a traffic accident, intraperitoneal injury is observed due to the compression of the seat belt on the full bladder, while extraperitoneal injury is observed due to pelvic fractures. Ultrasound can be helpful in diagnosis [18, 19, 20].

Although bladder rupture is very rare in the pediatric age group, it should be suspected in a patient with no urine output after blunt trauma, abdominal bloating, abdominal tenderness, and pain. As with other organ ruptures, a delayed diagnosis will increase morbidity and mortality. Extravasation of urine and blood into the peritoneal cavity due to bladder rupture may cause electrolyte imbalance, and uremia due to urine absorption [18, 19, 20].

Bladder injury can be diagnosed by demonstrating extravasation of IV contrast media on CT. At the same time, the location of the iv contrast agent on CT enables differentiation of intraperitoneal and extraperitoneal bladder rupture. Recognition of this is important in guiding treatment. Extraperitoneal injuries can be treated conservatively, whereas intraperitoneal injuries require immediate surgical repair [20, 21, 22, 25].

A suprapubic catheter may be required for bladder neck injuries [20].

4. Trauma anesthesia in a pediatric patient

Anesthetic management of a pediatric trauma patient has multiple issues to consider; management of the airway (may be traumatized or difficult), especially in the presence of a cervical spine injury, the possibility of full stomach (the stomach may be full of blood or secretions at least), the need for rapid sequence intubation, unstable or immediately decompensated hemodynamic status, particularly in the presence of traumatic brain injury (TBI), the possibility of significant hemorrhage and transfusion. Intraabdominal trauma occurs frequently (10%) and is the leading cause of initially unrecognized fatal injury and hemorrhage; the most injured organs, with the descending order, are the spleen, liver, renal, intestine then pancreas.

The mortality decreases with good prehospital care, appropriate triage, and effective resuscitation. Basic Advanced Trauma Life Support principles apply; initial stages of resuscitation, stabilization, and definitive management. Anesthetists should know the management of the trauma patient in the prehospital care and emergency department, to provide better intraoperative anesthetic management. A thorough yet quick history must be taken, regarding TBI, breathing, airway, intubation, manual in-line stabilization, and assessment of neurological and hemodynamic status. If the patient is not stabilized after two 20 ml/kg boluses of crystalloid, a transfusion of 10–20 ml/kg of packed red blood cells (PRBCs) should be prepared [8, 33]. After that, a secondary survey with diagnostic testing is completed. After all injuries are identified, definitive care and if necessary, surgical care should be decided.

The management of anesthetic induction should be performed regarding the child’s injury, presence, or absence of TBI, hemodynamic stability, and the anesthetists’ experience. Besides ASA standard monitorization, a functional intravenous line is essential. If not intubated before coming to the operating room, caution must be applied regarding difficult mask, airway, and full stomach (blood, mucus in the mouth, or previously aspirated or swallowed blood). If intubated, the location of the endotracheal tube should be verified.

If there is hemorrhage, damage control resuscitation will be planned and guided by both laboratory and clinical criteria, restrictive blood transfusion thresholds should be considered guiding allogenic blood transfusion. Damage control resuscitation is the strategy of treating massive hemorrhage with the transfusion of blood and blood components [35]. Crystalloid predominant resuscitation in the bleeding pediatric patient has negative influence on mortality and discouraged.

There is no consensus or universal protocols or definition of massive transfusion in pediatric patient. The dynamic definition of massive transfusion in children and neonates is suggested by Diab et al. [36] “transfusion of >50% of total body volume (TBV) in 3 hours, transfusion >100% TBV in 24 hours, or transfusion support to replace ongoing blood loss of >10% TBV per min”. Other definitions, transfusion requirements of 40 ml/kg in 12 hours or 80 ml/kg within 24 hours [37].

Protocols involving early and liberal use of a fixed ratio of red blood cells:fresh frozen plasma (FFP):platelets have been used, with most suggesting 1:1:1, while occasionally 2:1:1 has also been described [35, 38]. Consideration must be given to the patient’s volume, hemodynamic status, tissue oxygenation, hemorrhage control, coagulation abnormalities, large volume blood, and blood products administration problems like potassium, ionized calcium, acid–base balance changes, and hypothermia. Acidosis, hypothermia, and coagulopathy constitute the “deadly” triad.

Trauma-induced coagulopathy (TIC) can be managed by early identification, massive transfusion protocols (MTP), tranexamic acid, and recombinant factor VIIa usage, desmopressin, and prothrombin complex concentrate. If available, coagulation tests, including thromboelastogram (TEG), rotational thromboelastometry (RoTEM), and impedance aggregometry can be used to guide, evaluate, and inform TIC in children older than 1 year.

Pain management needs careful titration and judicious use of multimodal techniques to benefit from regional as well as pharmacological and non-pharmacological interventions.

5. Conclusion

Pediatric patients present a unique set of challenges for the emergency physician, pediatrician, surgeon, or pediatric anesthesiologist after abdominal trauma. One of the most common problems encountered in pediatric patients after abdominal trauma is that it is detected late and leads to poor outcomes due to improper management.

Since abdominal trauma is still the most important cause of mortality in pediatrics, the primary rule to reduce mortality in these patients is to diagnose and start treatment in the first hours immediately. Observation and re-evaluation should be our main goals in the management of abdominal trauma cases.

Initial FAST and then CT is important in the evaluation of these patients. However, in the detection of asymptomatic cases, CT together with FAST may give more accurate and reliable results in selected cases with a high index of suspicion.

Laparoscopy is a safe method in both the evaluation and treatment of selective blunt and penetrating abdominal injuries in hemodynamically stable patients. However, it may not be beneficial in patients with delayed findings.