What is the most appropriate initial step for a patient with a history of blunt abdominal trauma, stable vital signs, and mild right upper quadrant abdominal pain?

Refer Patient to Emergency Department for Further Evaluation with CT Imaging

This patient requires immediate referral to the emergency department for CT imaging with IV contrast, as blunt abdominal trauma mandates definitive imaging even in hemodynamically stable patients with mild symptoms, and delayed presentations of serious injuries are well-documented. 1

Why Emergency Department Referral is Essential

The American College of Emergency Physicians explicitly recommends that patients with blunt abdominal trauma should be referred to the emergency department for further evaluation with CT imaging, regardless of vital sign stability. 1 This is critical because:

• Over one-third of "asymptomatic" blunt trauma patients had organ injuries on imaging, and 43% of patients with no specific complaints had significant injuries. 1

• Right upper quadrant pain specifically raises concern for hepatobiliary injury, which occurs frequently in motor vehicle accidents and can progress to life-threatening hemorrhage even with delayed presentation. 2

• Blunt abdominal trauma carries significant risk for delayed presentation of serious injuries including hepatic lacerations, splenic injuries, bowel perforations, and retroperitoneal hemorrhage that may not manifest immediately with hemodynamic instability. 2

• The 2-week timeframe since injury does not exclude evolving pathology—delayed bowel perforation from vascular injury can occur hours to days later, and contained hepatic injuries may develop complications. 1, 2

Why Other Options Are Inadequate

Abdominal Ultrasound Alone (Option A) is Insufficient

While ultrasound can provide rapid bedside assessment, it has critical limitations that make it inadequate as the sole diagnostic modality in this scenario:

• FAST ultrasound has high specificity but notably low sensitivity (56-71%) for detecting intra-abdominal injuries in blunt trauma, meaning a negative FAST cannot exclude significant pathology. 2

• FAST requires 400-620 mL of free fluid to be detected reliably and is highly operator-dependent. 1

• Ultrasound is less sensitive than CT and does not make it a sufficient test to exclude abdominal injuries, particularly extraperitoneal or genitourinary injuries. 3

• In a series of 128 acute trauma patients, 11 of 19 injuries missed by ultrasound involved the genitourinary system. 3

Blood Work Alone (Option C) Cannot Rule Out Hemorrhage or Injury

Blood work alone cannot exclude significant pathology such as contained hepatic injuries or developing complications, even if hemoglobin levels are normal. 2 Laboratory testing does not provide anatomic information about organ injury or active bleeding.

Analgesics and Follow-up (Option D) is Dangerous

Providing analgesics and outpatient follow-up would be inappropriate and potentially dangerous because:

• The presence of abdominal tenderness after blunt trauma mandates advanced imaging regardless of vital sign stability. 1

• Never rely on clinical examination alone in blunt abdominal trauma from high-energy mechanisms, as up to 75% of patients have associated injuries that may not be clinically apparent initially. 2

• Do not delay imaging for "observation" in trauma patients—occult injuries can deteriorate rapidly. 2

• Bowel injury remains one of the most commonly missed injuries on initial imaging, with 20% of bowel injuries missed even on CT. 1

The Gold Standard: CT with IV Contrast in the Emergency Department

CT scan with intravenous contrast is the gold standard for evaluating blunt abdominal trauma in hemodynamically stable patients, with sensitivity of 95-97% and specificity of 94-95% for detecting intra-abdominal injuries. 1 The European trauma guidelines provide a Grade 1B recommendation for CT imaging in hemodynamically stable patients with suspected torso trauma or high-risk mechanism of injury. 2

The negative predictive value of CT for need for surgical intervention is 99.63%. 2 This means that a negative CT effectively rules out the need for immediate surgical intervention and allows for safe disposition decisions.

Clinical Pitfall to Avoid

Do not be falsely reassured by hemodynamic stability—this patient's stable vital signs do not exclude serious intra-abdominal pathology. The American College of Radiology emphasizes that hemodynamically stable patients with blunt abdominal trauma and abdominal tenderness should undergo CT imaging regardless of initial clinical appearance. 1