Right Upper-Quadrant Pain and a Normal Abdominal Ultrasound

Ahmed and Fogel present a common diagnostic problem: biliary-type symptoms in patients with normal abdominal ultrasounds.1 They present an algorithm that advocates either conservative management or a hepatobiliary scan, with measurement of gallbladder ejection fraction as the next step after routine laboratory testing. Endoscopic ultrasound (EUS) is not included in their algorithm; indeed, the authors minimize its potential utility, stating that it “might be useful in a subset of these patients.” They discuss the use of computed tomography, after which is “consideration given to performing EUS or MRCP [magnetic resonance cholangiopancreatography] for more detailed evaluation if suspicion is high.” The patient in their scenario ultimately is recommended for cholescintigraphy.

This algorithm should be modified to include EUS as an early diagnostic tool. Transabdominal ultrasound is not a perfect test for gallstones and biliary sludge; although highly specific, it has a sensitivity of less than 90% for cholelithiasis.2 Altered anatomy, obesity, and operator skill are significant limitations. In patients with negative abdominal ultrasounds but with typical biliary pain, EUS will find evidence of stones and sludge in more than half of patients.3 This group, likely to benefit from cholecystectomy, will not need additional imaging to evaluate for rare causes of abdominal pain, scintigraphy to document gallbladder dyskinesia, or biliary manometry to disprove sphincter dysfunction. EUS also is helpful in diagnosing intraluminal pathology, such as acid peptic disease, which mimics biliary colic. As such, EUS should be used before these tests, and should play a prominent role in the work-up of these patients.