Right Upper Quadrant Pain and a Normal Abdominal Ultrasound

A 30-year-old woman is referred for evaluation of a 1-year history of intermittent, debilitating, postprandial right upper quadrant pain associated with nausea and occasional vomiting. The pain can last from 30 minutes to 2 hours, often radiates to the upper back between the shoulder blades, and is not associated with bowel movements or exercise. The patient denies a history of weight loss, fever, chills, change in urine or stool color, or jaundice. She denies significant alcohol use. Trials of antacids, proton pump inhibitors, and antispasmodics have not been helpful. At times the pain has been severe enough to interrupt her daily activities. The patient recently presented to her local emergency department during an episode of pain. Blood work drawn in the emergency department included alanine aminotransferase 23 U/L (normal, 0–45 U/L), aspartate aminotransferase 29 U/L (normal, 15–41 U/L), alkaline phosphatase 86 U/L (normal, 25–125 U/L), bilirubin 0.6 mg/dL (normal, 0–1 mg/dL), amylase 101 U/L (normal, 25–161 U/L), and lipase 162 U/L (normal, 40–240 U/L). The patient reports that liver chemistries and amylase and lipase levels have been persistently normal during previous episodes of abdominal pain. A right upper quadrant ultrasound reveals a normal-appearing gallbladder without gallbladder wall thickening or gallstones. The intrahepatic and extrahepatic bile ducts are not dilated. The liver and limited views of the pancreas are also unremarkable. The patient underwent an esophagogastroduodenoscopy (EGD) 1 month ago that was normal.