Utility of serum pancreatic enzyme levels in diagnosing blunt trauma to the pancreas: a prospective study with systematic review.

INTRODUCTION: Reliability of serum pancreatic enzyme levels in predicting pancreatic injuries has been a parameter of interest and the present recommendations on its utility are based primarily on anecdotal observations. The aim of this study was to evaluate the utility of serum pancreatic enzyme assessment in predicting blunt pancreatic injury with imaging and surgical correlation and compare our results with a systematic review of literature till date.

METHODS: A prospective cohort study conducted over 4 years in a tertiary care referral centre with 164 consecutive patients who presented to the emergency department with a history of blunt abdominal trauma and had serum pancreatic enzyme assessment, USG and subsequent diagnostic CECT were analyzed. The CT findings and AAST grade of pancreatic injury, various intra-abdominal injuries and time elapsed since injury and other associated factors were correlated with serum pancreatic enzyme levels. For systematic review of literature MEDLINE database was searched between 1940 and 2012, also the related citations and bibliographies of relevant articles were analyzed and 40 articles were included for review. We compared our results with the systematic critique of literature till date to formulate recommendations.

RESULTS: 33(21%) patients had pancreatic injury documented on CT and were graded according to AAST. Statistically significant elevated serum amylase levels were observed in patients with pancreatic and bowel injuries. However, elevated serum lipase was observed specifically in patients with pancreatic injury with or without bowel injury. Combined serum amylase and lipase showed 100% specificity, 85% sensitivity in predicting pancreatic injury. Elevated (n=28, 85%) vs. normal (n=5, 15%) serum amylase and lipase levels showed sole statistically significant association with time elapse since injury to admission, with a cutoff of 3h.

CONCLUSIONS: Based on our results and the systematic review of the literature till date we conclude, persistently elevated or rising combined estimation of serum amylase and lipase levels are reliable indicators of pancreatic injury and is time dependent, nondiagnostic within 6h or less after trauma. In resource constrained countries where CT is not available everywhere it may support a clinical suspicion of pancreatic injury and can be reliable and cost-effective as a screening tool.