INTRODUCTION:
Serum amylase and lipase are important biomarkers to diagnose acute pancreatitis with a specificity of 89 and 93%, and sensitivity of 72% and 79%, respectively. Their elevation is common in pathologies such as acute cholecystitis, ketoacidosis, inflammatory intestinal disease, sepsis and renal insufficiency.
CASE DESCRIPTION/METHODS:
58 y/o male with type 2 diabetes mellitus, hypertension, and hyperlipidemia was admitted with generalized weakness, dizziness and multiple episodes of non-bloody watery diarrhea for one week. Physical exam was remarkable for left lower quadrant (LLQ) abdominal tenderness, bilateral lower extremity edema, and pulmonary congestion. Laboratory tests showed pre-renal acute kidney injury (AKI) with creatinine of 10.3, BUN of 121, metabolic acidosis, and hyperkalemia requiring emergent hemodialysis, leukocytosis of 17 per nL, and stool studies were positive for clostridium difficile infection (CDI). Interestingly he also had extremely elevated lipase of 3913 U/L and amylase of 1046 U/L in the absence of clinical and radiographic findings (CT and ultrasound abdomen) of acute pancreatitis. CDI was successfully treated with oral vancomycin. After a prolonged hospital course patient, his kidney function improved, and he did not require additional dialysis upon discharge.
DISCUSSION:
The diagnosis of pancreatitis requires the presence of two out three criteria including elevation of pancreatic enzymes 3 times or more above the upper normal limit (UNL), clinical presentation and radiologic findings suggestive of pancreatitis. Up to 10% of acute pancreatitis patients lack classic epigastric pain. In our patient the abdominal pain was located on the LLQ, likely related to CDI. The only suspicion for acute pancreatitis in this clinical case was the impressive 60 folds elevation of lipase and 10 fold elevation of amylase. In AKI, amylase has been shown to increase up to 10 folds the upper normal limit, while the lipase increase is usually less dramatic, reaching 3-5 folds the UNL. To identify the pancreas-originated enzyme increase we can perform additional tests including isoenzymes (isoamylase and isolipase), trypsin, and elastase levels. Elastase 1 is a highly specific enzyme for pancreatitis, not affected by reduced renal clearance found in AKI. In conclusion, an extreme elevation of amylase and lipase in the setting of severe AKI can be noted in the absence of acute pancreatitis. Interpretation of these laboratory values must be correlated with the clinical presentation.