Ammann's diagnostic criteria for chronic pancreatitis were published with the 1997 Zurich international workshop on chronic pancreatitis.

1) Recurrent pancreatitis and
2) ≥1 of the following:

• Calcifications in the pancreas
• Moderate or severe ductal lesions as defined by the Cambridge criteria
• Typical pancreatic histology of an adequate surgical specimen
• Persistent exocrine insufficiency (for ≥2 years)

The Cambridge classification divides chronic pancreatitis to five severity groups according to morphologic changes of the main pancreatic duct and its side branches. It was defined in 1983 in the Cambridge symposium.

The revised Atlanta classification of acute pancreatitis considers two overlapping phases with two peaks of mortality. The early phase usually last for the first week and the primary source of mortality is the systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF). In the late phase, which may last for weeks or months, local complications can (apart from persistent systemic inflammation) develop.

1) Interstitial edematous pancreatitis

Acute inflammation of the pancreatic parenchyma and peripancreatic tissues, without detectable tissue necrosis.

The original Balthasar score was developed and published in 1985. Originally, the score was based on unehnaced CT scans. It was later extended with the necrosis score to reflect also necrotic changes of the pancreatic parenchyma on contrast enhanced CT and their prognostic relevance and named CT severity index (CTSI).

Balthasar score