What is the next best diagnostic step in suspected acute gallstone pancreatitis?

In cases of suspected acute gallstone pancreatitis, the next best diagnostic step after clinical assessment is often a CT scan of the abdomen with contrast. This imaging modality is advantageous because it offers a comprehensive view of the pancreas and surrounding structures, allowing for the assessment of complications such as peritoneal fluid collections, necrosis, or abscess formation that could arise from the inflammation caused by pancreatitis.

Additionally, a CT scan can help confirm the presence of gallstones and visualize any potential obstructions in the biliary tree, which are critical in the management of pancreatitis. While ultrasound is a useful first-line imaging technique and can detect gallstones, a CT scan provides more detailed information about the pancreas itself and the extent of pancreatitis.

Endoscopic retrograde cholangiopancreatography (ERCP) is primarily a therapeutic procedure for managing biliary obstruction but is not typically the initial diagnostic step in acute pancreatitis. An MRI of the abdomen is less commonly used in this acute setting compared to CT because it is not as readily available in emergency situations and often takes longer to perform. Therefore, the CT scan stands out as the most appropriate next step in the management of suspected acute gallstone pancreatitis.