Abdominal Ultrasound is the Most Appropriate Next Step
For a vitally stable patient with mild right upper quadrant pain following a road traffic accident, abdominal ultrasound should be performed as the initial imaging study. 1, 2
Rationale for Ultrasound as First-Line Imaging
Ultrasound is rated 9/9 (usually appropriate) by the American College of Radiology as the first-choice investigation for right upper quadrant abdominal pain. 1, 3 This recommendation applies regardless of whether the pain is traumatic or atraumatic in origin.
The American College of Radiology Appropriateness Criteria explicitly state that ultrasonography is the initial imaging test of choice for patients presenting with right upper quadrant pain, with 96% accuracy for detecting gallstones and excellent ability to identify alternative diagnoses. 1
Ultrasound provides rapid, non-invasive evaluation without radiation exposure, can be performed at the bedside, and allows morphologic assessment of the liver, gallbladder, biliary tree, and can detect free fluid or solid organ injury from trauma. 1, 2
Why Not Emergency Department Referral?
A vitally stable patient with mild pain does not meet criteria for immediate emergency department transfer. 1 The patient's hemodynamic stability allows for outpatient diagnostic workup.
Emergency department referral would be appropriate if the patient develops hemodynamic instability, peritoneal signs, or if ultrasound reveals findings requiring urgent intervention (such as free fluid suggesting hemorrhage or organ rupture). 4
Why Not Blood Work Alone?
Laboratory testing without imaging has not yielded acceptable likelihood ratios sufficient to predict the presence or absence of acute abdominal pathology requiring intervention. 1
While complete blood count and liver function tests should be obtained, they cannot definitively rule out hemorrhage or identify the source of pain without imaging correlation. 3, 5
Blood work should be performed concurrently with ultrasound, not as a substitute for imaging. 3
Critical Clinical Algorithm
Perform right upper quadrant ultrasound immediately as the first diagnostic step. 1, 3 This evaluates for:
Obtain complete blood count and liver function tests concurrently with ultrasound. 3, 5
If ultrasound is negative or equivocal and clinical suspicion remains high, proceed to CT abdomen/pelvis with IV contrast. 1 CT has greater than 95% sensitivity for detecting solid organ injury, hemorrhage, and alternative diagnoses beyond what ultrasound can visualize. 3
If ultrasound reveals free fluid or solid organ injury, refer immediately to the emergency department for surgical evaluation. 4, 6
Important Clinical Pitfalls to Avoid
Do not skip ultrasound and proceed directly to CT unless the patient is hemodynamically unstable. 3 Ultrasound is more appropriate for initial evaluation and avoids unnecessary radiation exposure in a stable patient. 1
Do not assume that vital stability excludes significant intra-abdominal injury. 4 Delayed presentation of solid organ injury (particularly hepatic or splenic laceration) can occur hours to days after trauma, and ultrasound can detect subcapsular hematomas or free fluid before hemodynamic compromise develops. 6
Post-traumatic right upper quadrant pain specifically raises concern for hepatic injury, which ultrasound can readily identify. 2, 6 The liver is the most commonly injured solid organ in blunt abdominal trauma.