Chronic pancreatitis is characterized by longstanding inflammation of the pancreas owing to a wide variety of causes, including recurrent acute attacks of pancreatitis.

• Chronic pancreatitis affects three to nine out of 100,000 persons; 70 percent of cases are alcohol induced.

Pancreatic enzyme supplements reduce steatorrhea in persons with chronic pancreatitis, but it seems that they have no effect on pain.

• We do not know whether consuming a low-fat diet or avoiding alcohol consumption improves symptoms of chronic pancreatitis. We also do not know whether calcium or vitamin and antioxidant supplements are effective.

There is consensus that tramadol is the most effective oral opioid analgesic for reducing pain in persons with chronic pancreatitis; however, tramadol is associated with gastrointestinal adverse effects.

• We do not know whether nerve blocks are effective.

There is consensus that endoscopic and surgical pseu-docyst decompression or ductal decompression have benefits and harms; it is unclear which technique is best, and the choice often depends on local expertise.

• There is consensus that, despite complications, biliary decompression is essential in persons with chronic pancreatitis who have biliary obstruction.

Resection using pancreatoduodenectomy may be equivalent to localized excision of the pancreatic head in improving symptoms, but it reduces quality of life and increases intraoperative and postoperative complications. In clinical practice, resection using pancreatoduo-denectomy is usually reserved for when other surgical options, such as pseudocyst or duct decompression, are not feasible because of disease severity.

• There is consensus that distal pancreatectomy may be a viable option in persons with chronic pancreatitis limited to the tail of the pancreas and is most effective when multiple pseudocysts are present. Distal pan-createctomy is associated with complications in 15 to 50 percent of patients.

Definition

Pancreatitis is inflammation of the pancreas. The inflammation may be sudden (acute) or ongoing (chronic). Acute pancreatitis usually involves a single attack, after which the pancreas returns to normal. Chronic pancreatitis is characterized by long-standing inflammation of the pancreas owing to a wide variety of causes, including recurrent acute attacks of pancreatitis. Symptoms of chronic pancreatitis include recurring or persistent abdominal pain and impaired exocrine function. The most reliable test of exocrine function is the demonstration of increased fecal fat, although this test is typically not performed if imaging findings are consistent (particularly calcification of the pancreatic gland on computed tomography).

Diagnosis. There is no consensus on the diagnostic criteria for chronic pancreatitis. Typical symptoms include pain radiating to the back, and persons may present with malabsorption, malnutrition, or pancreatic endocrine insufficiency. However, these symptoms may occur in persons with more common disorders such as reflux disease and peptic ulcers (also more common with heavy alcohol consumption) and in persons with more serious diseases such as pancreatic or periampullary cancers. Diagnostic tests for chronic pancreatitis include fecal elastase measurement (to confirm pancreatic insufficiency) and imaging. Biopsy may be required to resolve diagnostic uncertainty.

Incidence and Prevalence

The annual incidence of chronic pancreatitis has been estimated in one prospective study and several retrospective studies to be between three and nine cases per 100,000 persons. Prevalence is estimated to be between 0.04 and 5 percent. Alcohol-induced chronic pancreatitis is usually diagnosed after a long history of alcohol abuse; alcohol is the most common cause.

Etiology

The TIGAR-O system describes the main predisposing factors for chronic pancreatitis: Toxic-metabolic (which includes alcohol induced [70 percent of all cases], smoking, hypercalcemia, hyperlipidemia, and chronic renal failure); Idiopathic (which includes tropical pancreatitis and may form in up to 20 percent of all cases); Genetic (which includes cationic trypsinogen, cystic fibrosis transmembrane regulator, and serine peptidase inhibitor, Kazal type 1, mutation); Autoimmune (which includes solitary and syndromic); Recurrent and severe acute pancreatitis (which includes postnecrotic and radiation induced); and Obstructive (which includes pancreatic divisum and duct obstruction owing to various causes). Although 70 percent of persons with chronic pancreatitis report excessive consumption of alcohol (i.e., more than 150 g per day) over a long period (more than 20 years), only one in 10 heavy drinkers develop chronic pancreatitis. This suggests an underlying genetic predisposition or polymorphism, although a conclusive link has not been established.

Prognosis

Mortality in persons with chronic pancreatitis is higher than in the general population, with a mortality rate 10 years after diagnosis estimated at 70 to 80 percent. Diagnosis is usually made at 40 to 48 years of age. Reported causes of mortality in persons with chronic pancreatitis are complications of disease or treatment; development of pancreatic cancer or diabetes; and continual exposure to risk factors for mortality, such as smoking and alcohol use.