Acute pancreatitis is sudden swelling and inflammation of the pancreas.

The pancreas is an organ located behind the stomach that produces chemicals called enzymes, as well as the hormones insulin and glucagon. Most of the time, the enzymes are only active after they reach the small intestine, where they are needed to digest food.

When these enzymes somehow become active inside the pancreas, they eat (and digest) the tissue of the pancreas. This causes swelling, bleeding (hemorrhage), and damage to the pancreas and its blood vessels.

Acute pancreatitis affects men more often than women. Certain diseases, surgeries, and habits make you more likely to develop this condition.

The condition is most often caused by alcoholism and alcohol abuse (70% of cases in the U.S.). Genetics may be a factor in some cases. Sometimes the cause is not known, however.

Other conditions that have been linked to pancreatitis are:

• Autoimmune problems (when the immune system attacks the body)
• Blockage of the pancreatic duct or common bile duct, the tubes that drain enzymes from the pancreas
• Damage to the ducts or pancreas during surgery
• High blood levels of a fat called triglycerides (hypertriglyceridemia)
• Injury to the pancreas from an accident

Other causes include:

• Complications of cystic fibrosis
• Hemolytic uremic syndrome
• Hyperparathyroidism
• Kawasaki disease
• Reye syndrome
• Use of certain medications (especially estrogens, corticosteroids, thiazide diuretics, and azathioprine)
• Viral infections, including mumps, coxsackie B, mycoplasma pneumonia, and campylobacter