Pancreatitis refers to inflammation of the pancreas, and can be acute or chronic. Acute attacks typically give severe abdominal pain which extends from the upper stomach through to the back and can cause effects ranging from mild swelling of the pancreas to life-threatening organ failure. Chronic pancreatitis is a slowly progressing disease that may involve a series of acute attacks, causing intermittent or constant pain as it permanently damages the pancreas.
The pancreas is a narrow, flat organ located deep in the abdominal cavity, behind the stomach and below the liver. It has exocrine tissues, which make powerful enzymes that help digest fats, proteins and carbohydrates. It also excretes bicarbonate, which helps neutralise stomach acids. It also has "islets" of endocrine tissue that produce the hormones insulin and glucagon, vital for the transport of glucose into body cells.
Normally, the pancreatic digestive enzymes are created and carried into the duodenum (first part of the small intestine) in an inactive form. It is thought that during an attack of pancreatitis these enzymes become activated while still in the pancreas and begin to digest and destroy it. Following acute pancreatitis, the gland can often heal without affecting its functions much or changing in structure, whereas chronic pancreatitis causes severe functional and structural change.
In developed countries one of the most common causes of acute pancreatitis (accounting for approximately 40% of cases) is gallstone disease. Heavy alcohol use is another major cause of acute pancreatitis accounting for at least 35% of cases. In 10-30% of cases, the cause is unknown.
The less common causes include:
- Drugs such as sodium valproate or morphine
- Viral infections such as mumps, Epstein-Barr or hepatitis A and B
- High plasma triglycerides (hypertriglyceridaemia) in diabetes, alcoholism or inherited conditions
- High plasma calcium (hypercalcaemia) in hyperparathyroidism or malignant disease
- Cystic fibrosis or Reye's syndrome in children
- Pancreatic cancer
- Surgery in the pancreas area (such as bile duct surgery) or trauma
In the past, alcohol consumption was believed to cause most cases of chronic pancreatitis. However, recent evidence indicates that, although alcohol contributes significantly to development of the disease, it is not the main cause for most patients. Among these include the following:
- Toxic and metabolic: Alcohol, high calcium in blood, rarely high lipids, some drugs, tobacco, toxins, chronic renal failure
- Idiopathic: cause unknown (after all other causes have been excluded)
- Genetic: Abnormal genes coding for pancreatic enzymes
- Autoimmune: Autoimmune chronic pancreatitis associated with inflammatory bowel disease
- Recurrent and severe acute pancreatitis
- Obstructive: Due to blocking of structures in the pancreas area
Autoimmune causes account for 5-6% while the cause cannot be identified in10-20% of all cases of chronic pancreatitis. The other causes mentioned above account for 70-80% of all causes of chronic pancreatitis.