Acute Idiopathic Pancreatitis With Normal Lipase: Case Report and Literature Review

Abstract

Introduction: Serum lipase level is considered a highly reliable test to rule out acute pancreatitis. Few previous cases of clinically proven acute pancreatitis, with normal lipase, have been reported in the setting of alcohol intake, gallstone, trauma, hypertriglyceridemia and medications. No prior case of acute idiopathic pancreatitis with normal lipase has been reported. Case: A 21-year-old woman presented to the emergency room with one-day history of severe, acute onset, epigastric pain. The pain was sharp, radiating to the back, and associated with nausea and vomiting. The patient had a similar episode several months prior. Review of systems was negative. There was no recent trauma. She had no significant past medical or surgical history. Patient quit smoking 2 years prior, did not use any alcohol or illicit drugs, nor was consuming any medications, including over the counter and herbal supplements. Family history was negative for hypertriglyceridemia, autoimmune and pancreatic/gallbladder related diseases. Physical examination was positive only for tenderness in the epigastric area. Laboratory studies revealed unremarkable complete blood count, comperhensive metabolic panel, amylase (46, nl=20-104 U/L) and lipase (46, nl=7-60 U/L). A CT scan of the abdomen and pelvis with contrast done the day of admission showed moderate peripancreatic and mesenteric inflammatory changes consistent with acute pancreatitis, without evidence of gallstones or cholelithiasis. Lipid panel and immunoglobulin-G4 level were normal and MRCP confirmed the CT scan findings. Patient was treated supportively with intravenous fluids and analgesics. Amylase and lipase levels remained normal throughout the hospital stay. Patient was discharged on day 7 with complete resolution of symptoms. Discussion: According to the ACG guidelines the diagnosis of acute pancreatitis requires 2 of the following: 1) characteristic abdominal pain 2) serum amylase and/or lipase more than 3 times the upper limit of normal; or 3) CT scan findings compatible with acute pancreatitis. Serum lipase rises within a few hours of symptoms onset in acute pancreatitis and it has a negative predictive value that approaches 100%. A normal serum lipase level in the setting of acute pancreatitis is an extremely rare occurrence. Conclusion: This report shows that acute pancreatitis with normal amylase and lipase levels can occur and, in appropriate clinical setting, abdominal imaging should be obtained to confirm the diagnosis.