Disease Information for Pancreatitis, acute: Definition

The diagnosis of acute pancreatitis is based on clinical findings and supported by an elevation of serum amylase and lipase; Most, but not all, patients with acute pancreatitis have hyperamylasemia; Typically the serum amylase level rises rapidly over the initial 2 to 12 hours of an attack, then slowly declines to its normal values over the next 3 to 5 days; The magnitude of hyperamylasemia has no prognostic value; Hyperamylasemia is not specific to pancreatitis, although the greater the elevations of the serum amylase, the more it tends to signify acute pancreatic damage; Apart from acute pancreatitis, hyperamylasemia may result in small bowel obstruction, perforation, or infarction; a perforated duodenal ulcer; or liberation of amylase into the circulation from nongastrointestinal sources, such as the lung, fallopian tubes, and salivary glands; Alternatively, hyperamylasemia may be caused by release of amylase from certain tumors or reduced renal clearance of amylase owing to renal failure; Pancreatic hyperamylasemia can occur after ERCP or after passage of common duct stones even in the absence of pancreatitis; Macroamylasemia, an unusual but not rare condition, occasionally can cause isolated elevation of the serum amylase level; In this condition, amylase is bound to an abnormal serum protein: The complex is not cleared by the kidney and results in hyperamylasemia. Macroamylasemia should be suspected when hyperamylasemia is associated with low urinary amylase levels; Hypertriglyceridemia may depress serum amylase measurements spuriously; diluting the serum unmasks the increased serum amylase level; Amylase activity in blood is composed of isoenzymes from the pancreas and salivary glands; Pancreatic isoamylase normally accounts for approximately 40% of total serum amylase activity; In acute pancreatitis, serum pancreatic isoamylase increases substantially; These increases also can occur in conditions other than acute pancreatitis, including intestinal injury and renal insufficiency, rendering its measurement nonspecific;

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