Initial presentation with atypical signs and symptoms; including equivocal amylase and lipase values (possibly confounded by acute kidney injury or chronic kidney disease) and when diagnoses other than pancreatitis may be possible (bowel perforation, bowel ischemia, etc). Initial imaging. CT Abdomen and Pelvis In patients with acute abdominal pain, there are often multiple potential etiologies to consider, including peptic ulcer disease, bowel perforation, and mesenteric ischemia, among others. Laboratory studies, specifically serum amylase and lipase, can help differentiate AP from these other considerations. Although serum amylase level is the most commonly used biochemical marker of AP, levels of amylase less than 3 times that of normal levels at the time of diagnosis can be related to rapid clearing. In contrast, serum lipase rises later but may be a more reliable marker of AP because of its longer half-life [16]. Additionally, significantly lower serum amylase and lipase levels have been observed in patients with alcoholic AP, perhaps as a result of poor pancreatic exocrine function [14]. Elevated triglyceride levels are also known to interfere with the serum amylase assay; conversely, both amylase and lipase may be elevated in patients with renal insufficiency without AP [16]. CT abdomen and pelvis without IV contrast can help in making the diagnosis of AP by assessing the presence of peripancreatic stranding and fluid collections. However, stratification of disease severity cannot be performed because of the lack of assessment of pancreatic necrosis. Given the limitations of early CT with or without IV contrast for stratification of disease severity, performing both CT abdomen and pelvis without and with IV contrast does not add to the diagnosis of AP, and CT abdomen and pelvis with IV contrast is preferred to exclude other etiologies of abdominal pain.
Acute Pancreatitis. Initial presentation with atypical signs and symptoms; including equivocal amylase and lipase values (possibly confounded by acute kidney injury or chronic kidney disease) and when diagnoses other than pancreatitis may be possible (bowel perforation, bowel ischemia, etc). Initial imaging. CT Abdomen and Pelvis In patients with acute abdominal pain, there are often multiple potential etiologies to consider, including peptic ulcer disease, bowel perforation, and mesenteric ischemia, among others. Laboratory studies, specifically serum amylase and lipase, can help differentiate AP from these other considerations. Although serum amylase level is the most commonly used biochemical marker of AP, levels of amylase less than 3 times that of normal levels at the time of diagnosis can be related to rapid clearing. In contrast, serum lipase rises later but may be a more reliable marker of AP because of its longer half-life [16]. Additionally, significantly lower serum amylase and lipase levels have been observed in patients with alcoholic AP, perhaps as a result of poor pancreatic exocrine function [14]. Elevated triglyceride levels are also known to interfere with the serum amylase assay; conversely, both amylase and lipase may be elevated in patients with renal insufficiency without AP [16]. CT abdomen and pelvis without IV contrast can help in making the diagnosis of AP by assessing the presence of peripancreatic stranding and fluid collections. However, stratification of disease severity cannot be performed because of the lack of assessment of pancreatic necrosis. Given the limitations of early CT with or without IV contrast for stratification of disease severity, performing both CT abdomen and pelvis without and with IV contrast does not add to the diagnosis of AP, and CT abdomen and pelvis with IV contrast is preferred to exclude other etiologies of abdominal pain.