Rod's site has good info about Pancreatitis

The cells of the pancreas secrete the enzymes used for digestion, normally the pancreas is protected from premature activation of these digestive enzymes, which could result in digesting the pancreas itself. Pancreatitis occurs when the enzymes are activated while still in the pancreas, thereby causing death to its tissues. It is extremely painful.

Chronic pancreatitis is a continuous inflammation which can cause permanent damage to the tissues of the pancreas' tissues. This results in insufficient creation of enzymes, resulting in exocrine pancreatic insufficiency (EPI). [Easy to treat now with the addition of enzymes to each meal]

Chronic pancreatitis may result in diabetes mellitus

This is aimed at veterinary professionals, I have pulled out some relevant bits, and tried to make them easier to understand:

clinical signs of Pancreatitis
In dogs, the classic clinical signs of pancreatitis are:
• anorexia
• vomiting
• abdominal pain.
Other signs may
• nausea
• drooling
• depression
• diarrhea
• fever.

Diagnosing pancreatitis can be difficult because these signs are often associated with other diseases.

Animals may develop pancreatitis from:
• high-fat and, possibly, lowprotein diets
• a genetic predisposition
• surgical interference secondary to hypovolemic, hypotensive, or ischemic insults to the pancreas
• trauma.

Drugs may possibly cause pancreatitis.

Treatment for acute pancreatitis
• Provide saline suport - IVs
• Provide plasma protein
• Administer analgesics for pain.
• Remove causal agent, if identified.
• Administer antiemetics if vomiting persists despite no food being taken.
• Administer antibiotics if there’s a potential for bacterial infection spreading.
• Insert feeding tube (in severe cases)

Chronic pancreatitis
• Prescribe a low-fat diet with adequate protein content.
• Find drug alternatives for animals taking drugs known to cause pancreatitis
• Regular blood tests