What is the pathogenesis of pancreatitis that can lead to hypovolemia?

Pancreatitis is inflammation of the pancreas that can be caused by infectious organisms (bacteria, fungi, viruses, etc.) or can be due to non-infectious causes (chemical irritation, trauma, etc.). The pancreas is not well encapsulated, so the inflammatory chemicals often leak from the pancreas into the surrounding mesentery, which starts a sterile (non-infectious) peritonitis. If the peritonitis becomes diffuse (throughout the abdomen), the inflammatory response can pull so much plasma from the blood that you can become clinically dehydrated, or hypovolemic.