Acute pancreatitis results in enzymic necrosis of tissues

Acute pancreatitis is an important cause of severe abdominal pain and enters the differential diagnosis of the acute abdomen.
Severe acute inflammation and necrosis of the pancreas leads to liberation of the powerful digestive enzymes, resulting in extensive enzyme-mediated local tissue necrosis, particularly fat necrosis.

A complication of the development of acute pancreatitis is the conversion of the necrotic pancreas into a cyst filled with serosanguinous fluid (pancreatic pseudocyst).

Clinically most patients with acute pancreatitis recover.
In severe disease chemical peritonitis and shock may develop. This may predispose to ARDS.

In acute pancreatitis

The pancreas appears oedematous and is commonly haemorrhagic.
Pancreatic tissue becomes necrotic and may become semi-liquid.
Lipase released from the pancreatic acini causes the development of foci of fat necrosis.

Severe pancreatic atrophy occurs with cystic fibrosis

Chronic pancreatitis is mainly caused by chronic alcohol abuse

Chronic pancreatitis results from chronic inflammation and fibrosis in the gland.
The four pathological features of chronic pancreatitis are continued chronic inflammation, fibrous scarring, loss of pancreatic parenchymal elements, and duct strictures and ectasia with formation of intrapancreatic calculi.

Gallstones are not felt to play an important role in chronic pancreatitis, in contrast to their importance in acute pancreatitis.

Patients have recurrent bouts of severe abdominal pain, with eventual development of malabsorption, and diabetes mellitus as pancreatic parenchyma is destroyed.
Episodes of acute pancreatitis may complicate chronic pancreatitis.