This patient presents to the emergency department with upper abdominal pain, nausea, and vomiting. The physical exam demonstrates fever, tachycardia, and focal right upper quadrant abdominal tenderness. Differential diagnoses to consider include cholecystitis, choledocholithiasis, cholangitis, hepatitis, pancreatitis, and ruptured peptic ulcer. The ultrasound image provided shows a thickened gallbladder wall (>4mm) and a gallstone present. See the labeled image below.

Signs of acute cholecystitis on ultrasound include a thickened gallbladder wall, pericholecystic fluid (anechoic (black) fluid around gallbladder), the presence of a gallstone (hyperechoic (white) with posterior shadowing), sonographic Murphy sign (tenderness when the transducer is pressed into gallbladder), and a dilated gallbladder. This patient has some but not all sonographic signs of cholecystitis. However, the age, obese body habitus, fever, and location of the pain support a diagnosis of acute cholecystitis (Choice B). Treatment of acute cholecystitis involves IV hydration, parenteral pain management and antiemetics, IV antibiotics, and surgical consultation for cholecystectomy. Biliary colic (Choice A) is less likely given the ultrasound findings and fever on exam. If the patient’s vital signs were normal and the ultrasound showed gallstones with no other sonographic signs of cholecystitis, biliary colic would be more likely. Gastritis (Choice C) does not cause fever or the sonographic signs illustrated above. Gallstones are the most common cause of pancreatitis (Choice D), but there is focal tenderness over the gallbladder in the right upper quadrant. Additional findings, such as an elevated lipase level, pain that radiates to the back, or a history of alcohol abuse would make pancreatitis a more likely diagnosis. Correct Answer: B