What are the predictors of post-ERCP pancreatitis, and how useful are they?

Acute pancreatitis is one of the major complications of ERCP. It is of paramount importance that we accurately identify which patients will go on to develop post-ERCP pancreatitis. As most ERCPs are performed on an outpatient basis, early evaluation can allow safe discharge of the majority of patients who will not develop post-ERCP pancreatitis or develop only mild symptoms that will be self-limited. Alternatively, early detection of those patients who will go on to develop moderate or severe post-ERCP pancreatitis can guide decisions regarding hospital admission and aggressive management and can help direct the use of targeted therapies that have the potential to prevent or mitigate pancreatic inflammation. Thus, significant efforts have focused on trying to identify predictors of post-ERCP pancreatitis. These parameters can be organized into three categories of tests: 1) pancreatic enzymes as markers of pancreatic injury: serum amylase/urine amylase; 2) markers of proteolytic activation: trypsinogen, trypsinogen activation peptide; 3) markers of systemic inflammation: C-reactive protein, various interleukins such as IL-6 and IL-10. A serum amylase level greater than 4-5 times the upper reference limit in conjunction with clinical symptoms has been shown to be an accurate and reliable predictor of post-ERCP pancreatitis. However, the exact timing and level of amylase elevation remains debatable. Urine testing of amylase and trypsinogen-2 in post-ERCP patients has also been shown to be highly sensitive and specific for detecting pancreatitis. The main advantage of these urinary markers is that they are available as rapid dipstick tests. Serum trypsinogen-2 levels have also been studied in post-ERCP pancreatitis patients; high levels seem to correlate with severity of disease. Among the markers of systemic inflammation, serum CRP is an accurate and readily available laboratory test for predicting severity of post-ERCP pancreatitis, but it appears to be helpful at 24-48 hours and, therefore, is not an early marker. Several other markers remain investigational and have not yet found wide clinical applicability.