In a child who sustained a direct bicycle handlebar impact to the upper abdomen and presents with epigastric pain, tenderness, nausea, vomiting, and an inconclusive focused assessment with sonography for trauma (FAST), which abdominal organ is most likely injured?

Pancreas is Most Likely Injured

In a child with bicycle handlebar injury presenting with upper abdominal pain, nausea, vomiting, and an inconclusive FAST, the pancreas (Option C) is the most likely injured organ.

Why Pancreas is the Answer

Mechanism-Specific Injury Pattern

• Bicycle handlebar injuries specifically cause pancreatic trauma in children through direct compression of the pancreas against the vertebral column during upper abdominal impact 1.
• The World Journal of Emergency Surgery identifies bicycle/handlebar injuries as one of the most common causes of pediatric duodenal and pancreatic injury, occurring in 70-78% of pediatric cases 1.
• Motor vehicle crashes and bicycle handlebar injuries are the most frequent causes of pediatric pancreatic injury 1.

Why FAST is Inconclusive for Pancreatic Injury

• FAST has poor sensitivity (68-91%) for detecting pancreatic injuries and routinely misses them 2.
• E-FAST is not recommended to routinely diagnose pancreatic trauma, as it has limited role in detecting acute pancreatic injuries 1, 2.
• Less than half of pediatric patients with abdominal injury have free fluid detectable on FAST, further limiting its utility 3, 4.
• The American College of Emergency Physicians emphasizes that negative or inconclusive FAST does not exclude significant intra-abdominal injury 2.

Clinical Presentation Matches Pancreatic Injury

• Patients with pancreatic injury typically present with epigastric pain, nausea, and vomiting 6-24 hours after injury 1.
• The clinical presentation described (upper abdominal pain, tenderness, nausea, vomiting) is classic for pancreatic trauma 1.

Why Not the Other Options

Spleen (Option A) - Unlikely

• Spleen injuries produce significant hemoperitoneum that FAST readily detects with sensitivity approaching 96-100% 2.
• If FAST is unremarkable, significant spleen injury is unlikely because this highly vascular organ bleeds into the peritoneal cavity, which FAST detects effectively 2.
• While spleen is the most common organ injured in pediatric blunt abdominal trauma overall 4, handlebar injuries have a different injury pattern.

Liver (Option B) - Unlikely

• Liver injuries typically present with right upper quadrant pain and would show free fluid on FAST if significant 2.
• Both liver and spleen injuries produce free intraperitoneal fluid that E-FAST readily detects 2.
• Although one study found liver laceration as the most common injury in bicycle accidents 5, this conflicts with the mechanism-specific data showing pancreatic predominance in handlebar injuries 1.

Urinary Bladder (Option D) - Anatomically Inconsistent

• The bladder is located in the pelvis, not the upper abdomen, making this anatomically inconsistent with handlebar impact to the upper abdomen 2.
• The clinical presentation of epigastric/upper abdominal pain does not match bladder injury location 2.

Critical Next Steps

Immediate Diagnostic Workup

• CT scan with intravenous contrast is essential for diagnosing pancreatic injuries in hemodynamically stable patients (sensitivity 97%, specificity 95%) 2.
• CT is the gold standard and specifically superior for detecting pancreatic injuries that FAST routinely misses 2, 3.

Laboratory Monitoring

• Serial measurement of serum amylase and lipase starting 3-6 hours after injury is crucial because pancreatic injury findings are time-dependent 2.
• Serum lipase is more specific than amylase for pancreatic injury 1.
• Measuring amylase and lipase levels every 6 hours is recommended, as accuracy improves when measured more than 3 hours after injury 1.
• Normal amylase at admission does not exclude pancreatic injury (up to 40% of patients have normal initial levels) 1.

Follow-up Imaging

• Elevated or rising enzyme levels mandate further investigation with CT scan, even if initial imaging is negative 2.
• Repeat CT scan within 12-24 hours should be considered in patients with high clinical suspicion despite negative initial imaging 2.
• Pancreatic injuries may not be evident on initial CT scanning 4.

Common Pitfalls to Avoid

• Do not rely on FAST alone or repeat FAST exams when mechanism suggests solid organ injury 2.
• Do not dismiss normal initial amylase/lipase values - they can be normal in up to 40% of pancreatic injuries initially 1.
• Do not delay CT imaging in hemodynamically stable patients with handlebar mechanism and upper abdominal symptoms 2, 3.
• Be aware that mean delay from accident to presentation can be 34.5 hours, and injuries may not be realized during initial admission 6.
• Children with an imprint made by the handlebar edge on the abdominal wall should be treated with heightened suspicion for serious internal injury 6.