What is the initial workup for a child with an abdominal injury?

Initial Workup for Pediatric Abdominal Injury

Immediate Assessment Priority

In a hemodynamically stable child with suspected abdominal injury, contrast-enhanced CT of the abdomen and pelvis is the gold standard imaging modality, while unstable children require immediate resuscitation with blood products and emergent surgical intervention. 1, 2

Hemodynamic Status Determines the Pathway

For Hemodynamically Unstable Children:

• Proceed directly to emergent laparotomy if the child remains hypotensive despite maximal resuscitative efforts (transfusion >50% of total blood volume), has free intraperitoneal air, gunshot wound, or evisceration 3
• Resuscitate with blood products rather than prolonged crystalloid administration 2
• Non-operative management is contraindicated in the setting of unresponsive hemodynamic instability or peritonitis 1

For Hemodynamically Stable Children:

The workup follows this algorithmic approach:

Step 1: Clinical Evaluation

Look for these specific high-risk features:

• Abdominal pain, distension, vomiting, abdominal wall bruising, hypoactive/absent bowel sounds - these suggest intra-abdominal injury 1
• Mechanism of injury - motor vehicle trauma causes 72% of pediatric abdominal injuries; high-energy deceleration trauma warrants imaging regardless of hematuria presence 1, 4
• Timing of symptoms - hollow viscous perforations are symptomatic from onset, while solid organ injuries may have delayed presentation 4
• Associated injuries - 29% have closed head injury, 43% have fractures 4

Step 2: Laboratory Testing

• Liver transaminases and pancreatic enzymes - abnormal values may indicate occult abdominal trauma even without obvious clinical findings 1
• Hematocrit monitoring - drop in hematocrit associated with any degree of hematuria warrants imaging in high-energy trauma 1

Step 3: Imaging Selection

Primary Imaging Modality:

Contrast-enhanced CT abdomen and pelvis with delayed urographic phase (5-minute delay) is the definitive study 1

This protocol provides:

• Detection of solid organ injuries (spleen, liver, kidneys, pancreas, adrenal glands) 1
• Identification of hollow viscous injuries (especially duodenum and bowel) - which occur disproportionately more in abuse cases 1
• Assessment of urinary tract injuries and collecting system damage 1
• Detection of free fluid, contrast blush, and pseudoaneurysms 1

Critical caveat: Non-contrast CT is inadequate and should never be used for abdominal trauma evaluation 1

Alternative/Adjunctive Imaging:

Ultrasound (FAST exam) has significant limitations in pediatric abdominal trauma:

• Less than 50% of children with abdominal injury have free fluid detectable by FAST 3
• FAST and standard ultrasound are less sensitive than CT for detecting hemoperitoneum and solid organ injuries 1
• Best role: Initial rapid assessment in unstable patients or as screening in children with mild symptoms and hematuria <50 RBCs/HPF 1
• Can be used for follow-up in hemodynamically stable patients 1

Contrast-enhanced ultrasound (CEUS):

• Consider in pregnant women, fertile women, or when radiation exposure is a concern 1
• Useful for detecting extravasation, thrombosis, and pseudoaneurysms 1
• Not recommended for suspected urinary tract/collecting system injuries 1

MRI:

• Alternative when radiation exposure is a concern (pregnant patients) 1
• Not practical in acute trauma settings due to longer examination times 1

Step 4: Additional Mandatory Imaging in Specific Contexts

If Child Abuse is Suspected:

• Skeletal survey is mandatory in all children ≤24 months with thoracoabdominal injury, as most have polytrauma 1
• Head CT or MRI should be performed even without obvious neurological symptoms, as up to 10% of abused children have intra-abdominal injury and often have concomitant head trauma 1
• Key distinguishing features of abuse: younger age, delayed presentation, bowel and pancreatic injuries disproportionately common, 6-fold increased mortality compared to accidental trauma 1

If Renal/Urological Injury Suspected:

• Delayed urographic phase (5-minute) is essential to identify urinary extravasation 1
• Indicated in: high-energy/penetrating/decelerating trauma, drop in hematocrit with any hematuria, hypotension after deceleration regardless of hematuria 1

Step 5: Management Based on Imaging

Non-operative management (NOM) is first-line for hemodynamically stable children with blunt trauma, regardless of injury grade 1

Requirements for NOM:

• Capability for continuous monitoring 1
• Immediately available operating room 1
• Immediate access to blood products 1
• Trained surgeons and angiography capability 1
• Consider transfer to dedicated pediatric trauma center for moderate-severe injuries 1

NOM should be attempted even with concomitant head trauma unless instability is due to intra-abdominal bleeding 1

Common Pitfalls to Avoid

1. Do not assume abdominal symptoms indicate abdominal pathology in head trauma - if both head and abdominal trauma are present, head CT takes priority as vomiting may indicate increased intracranial pressure 5

2. Do not rely on FAST alone - negative FAST does not rule out significant injury in children 3

3. Do not use non-contrast CT - it is inadequate for detecting abdominal trauma 1

4. Do not miss delayed presentations - bowel perforations and pancreatic injuries may not be evident on initial CT and require clinical vigilance 3

5. Do not forget the delayed urographic phase when renal injury is suspected - standard CT phases miss collecting system injuries 1

6. Do not perform routine CT screening in the absence of clinical indicators - this unnecessarily exposes children to radiation 1

7. In children with mild symptoms, minimal findings, and hematuria <50 RBCs/HPF with no other CT indications, ultrasound with blood tests may be sufficient for initial evaluation 1