Elevated serum amylase usually returns to normal after 7 days of acute pancreatitis. If it remains elevated after 7 days, the possible causes include all except:
In acute pancreatitis, the serum amylase and lipase are elevated within 24 hours of onset and remains for 3-7 days. Levels return to normal within 7 days unless there is pancreatic ductal disruption, ductal obstruction, or pseudocyst formation. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 2631
Pancreatic ductal disruption
Pancreatic ductal obstruction
Pseudocyst formation
Chronic calcific pancreatitis