Pancreatic pseudocysts: a biochemical evaluation of proteases and protease inhibitors in plasma.

A biochemical evaluation was performed on plasma from eight patients developing a pancreatic pseudocyst during acute pancreatitis attacks and from six patients with a known pseudocyst. Patients developing an acute pancreatic pseudocyst had high levels of activated trypsin in complex with alpha 1-protease inhibitor, together with a probable activation of the kinin, complement, coagulation and fibrinolytic systems. Profound changes were also seen in several protease inhibitors, indicating consumption of the inhibitors. The changes did, however, not differ from those seen in severe acute pancreatitis attacks in which no pseudocyst developed. Patients with chronic pancreatic pseudocysts had biochemical changes similar to those seen in moderate pancreatitis attacks, without any overt cascade system activation. At convalescence, however, these patients had biochemical signs of leakage from the pancreas and an ongoing proteolytic activity.