Physiology of Pancreatitis.

Pancreatitis is a disorder in which the enzymes that are normally secreted to help the digestive process and balance glucose levels are activated inside of the pancreas due to inflammation. This causes the pancreas to begin attacking and damaging the same cells that produce these enzymes. The reason these enzymes begin to activate early is that the pancreas becomes inflamed which can be due to a number of issues, some of them being heavy alcohol use, gallstones, infections and certain medications. Pancreatitis exist in two different forms acute and chronic, acute being the lesser of the two.

Acute pancreatitis typically develops very quickly but resolves itself within a matter of days to weeks, although it can be considered life threatening acute pancreatitis it's typically the less severe version of pancreatitis.

Chronic pancreatitis however is considered to be a more threatening version of this disease because of its prolonged damage on the pancreas. This form of pancreatitis is typically brought on because of the pancreas has become permanently injured, order heavily scarred. Permanent injury or scarring of the pancreas can come from either stress, excessive alcohol use or less commonly drug use. Because of the chronic nature of this disease and increase damage of the pancreas tumors as well as diabetic issues are typically seen after just a few years of this prolonged disease.

References: 

http://www.gastro.org/patient-center/digestive-conditions/pancreatitis#Differences%20Between%20Acute%20and%20Chronic%20Pancreatitis

http://www.medicinenet.com/pancreatitis/page2.htm#what_are_the_causes_of_acute_pancreatitis