Acute pancreatitis is acute inflammation of the pancreas and is a common cause of acute abdominal pain. The incidence in the UK is approximately 56 cases per 100,000 people per year. Around 50% of cases are caused by gallstones, 25% by alcohol and 25% by other factors. In 25% of cases, acute pancreatitis is severe and associated with complications such as respiratory or kidney failure, or the development of abdominal fluid collections. In these more severe cases, people often need critical care and a prolonged hospital stay, and the mortality rate is 25%. The overall mortality rate in acute pancreatitis is approximately 5%.
Chronic pancreatitis is a continuous prolonged inflammatory process of the pancreas that results in fibrosis, cyst formation and stricturing of the pancreatic duct. It usually presents with chronic abdominal pain but it can sometimes be painless. The clinical course is variable but most people with chronic pancreatitis have had 1 or more attacks of acute pancreatitis that has resulted in inflammatory change and fibrosis. In some people, however, chronic pancreatitis has a more insidious onset. The intensity of pain can range from mild to severe, even in people with little evidence of pancreatic disease on imaging.
The annual incidence of chronic pancreatitis in western Europe is about 5 new cases per 100,000 people, although this is probably an underestimate. The male to female ratio is 7:1 and the average age of onset is between 36 and 55 years. Alcohol is responsible for 70–80% of cases of chronic pancreatitis. Although cigarette smoking is not thought to be a primary cause in itself, it is strongly associated with chronic pancreatitis and is thought to exacerbate the condition. Chronic pancreatitis may be idiopathic or, in about 5% of cases, caused by hereditary factors (in these cases there is usually a positive family history). Other causes include hypercalcaemia, hyperlipidaemia or autoimmune disease.
Chronic pancreatitis causes a significant reduction in pancreatic function and the majority of people have reduced exocrine (digestive) function and reduced endocrine function (diabetes). They usually need expert dietary advice and medication. Chronic pancreatitis can also give rise to specific complications including painful inflammatory mass and obstructed pancreatic duct, biliary or duodenal obstruction, haemorrhage, or accumulation of fluid in the abdomen (ascites) or chest (pleural effusion). Managing these complications may be difficult because of ongoing comorbidities and social problems such as alcohol or opiate dependence. Chronic pancreatitis significantly increases the risk of pancreatic cancer. This risk is much higher in people with hereditary pancreatitis.