Severe Acute Pancreatitis, Normal Serum Amylase and Lipase

Abstract

Purpose: INTRODUCTION In the appropriate clinical context, serum elevations of amylase and lipase often confirm the diagnosis of pancreatitis. We present a case of acute pancreatitis with normal amylase and lipase despite the objective evidence of pancreatitis. Methods: CASE A 33 year old man presented to our institution with 4 day history of upper abdominal pain, fever, and nausea with episodes of vomiting. The pain was intermittent, radiated to the back, relieved by episodes of vomiting and made worse by eating. The patient's medical history was remarkable for diabetes mellitus and he admitted to alcohol binges. His last alcohol binge was two weeks before presentation. His home medications included insulin and promethazine. A review of the patient's systems was largely unrevealing. Physical examination revealed a young man in discomfort, with a temperature of 38.2°C, pulse rate of 106 bpm, respiratory rate of 24 and BP of 126/72 mmHg. He had a BMI of 38.2, central obesity and mild epigastric tenderness. Laboratory test results were as follows: Hemoglobin, 10.2 g/dL; WBC, 6.4 × 109/L; Platelets, 332 × 109/L; Creatinine, 0.8 mg/dL; BUN, 4; Amylase, 25 u/L; Lipase 175 u/L. Liver associated enzymes, serum electrolytes and lipid panel were unremarkable. A CT scan performed the same day showed features consistent with severe, hemorrhagic pancreatitis. Based on the CT findings a diagnosis of acute necrotizing pancreatitis was made. He responded to fluids and pain control and was discharged home on the 4th day of hospitalization. Results: DISCUSSION Acute pancreatitis relies on history, clinical findings and the presence of biochemical markers of pancreatic injury for diagnosis. This is often complemented by imaging studies at the appropriate timing. A raised level of serum amylase and lipase activity 3–4 times the upper limit of normal supports the diagnosis of acute pancreatitis in the proper clinical context. Serum amylase may be normal in 19–32% of cases at the time of hospital admission, as a result of delayed presentation or exocrine pancreatic insufficiency. Normal amylase levels have been reported in alcoholics and elderly patients with acute pancreatitis however normal lipase levels in severe acute pancreatitis has not, to the best of our knowledge, been reported. Serum lipase activity remains increased for 8–14 days, while amylase remains elevated for 3–5 days. Conclusion: Though we are tempted to attribute the findings of normal lipase and amylase in our patient to delayed presentation to the hospital, we suspect that the presentation of acute pancreatitis in the presence of normal amylase and lipase is rare, and hope to illustrate how this entity can be missed without the benefit of imaging modality.