Undetected fatal acute pancreatitis: why is the disease so frequently overlooked? An analysis of postmortem investigations between 1980 and 1985 revealed 43 patients with acute pancreatitis. In 13 (30.2%) of them, the diagnosis was first established at autopsy. In eight of the latter patients, the diagnosis could have been present on admission. The etiology was alcoholism in three patients, hypothermia in one, biliary tract disease in one, and unknown in three patients. In five patients, acute pancreatitis developed after gastric, pancreatic, or biliary tract surgery. Abdominal pain was present in only one patient. Amylase levels had been estimated in 11 patients, but the level was in the diagnostic range (greater than or equal to 3 times of upper normal level) in only four. Consequently, ultrasound examination was performed in only two of the latter four patients, but failed to show the pancreas because of intestinal gas. To diagnose acute pancreatitis at an earlier stage and to improve therapy and prognosis, we recommend that serum amylase levels be measured and ultrasound examination be performed. If the results are inconclusive, this should be followed by computed tomography for all abdominal emergency cases and for patients who have undergone cardiopulmonary or upper abdominal surgery, especially when the patients deteriorate or fail to improve postoperatively. 