The raised ALP and GGT along with the high bilirubin suggest there is likely to be obstructive jaundice, which is jaundice caused by obstruction of biliary outflow. The causes of obstructive jaundice include gallstones (most common), primary biliary cirrhosis causing intrahepatic obstruction, cancer of the head of the pancreas, strictures or extrinsic compression by enlarged lymph nodes.

Although it is possible that there is pancreatic cancer present, it usually presents as a painless progressive jaundice and weight loss rather than an acute painful episode. 

In Sally’s case, as she came in with epigastric pain radiating to the back alongside nausea and vomiting, it is essential to rule out pancreatitis. Sally’s amylase, in fact, was markedly raised leading to a suspicion of acute pancreatitis. The image of obstructive jaundice along with acute pancreatitis points to the presence of gallstones.