Family doctor

What is pancreatitis?

Pancreatitis is an inflammation of the pancreas, which is an organ within the upper abdomen responsible for the production of insulin and glucagon (which are released into the blood stream) and for certain enzymes necessary for the digestion of food (e.g. lipase), which are released via the pancreatic duct into the upper small bowel, where they aid the breakdown of food.

Pancreatitis is described as acute or chronic. Acute pancreatitis is a condition from which the sufferer (usually) recovers, because the condition is self-limited and the pancreatic tissue returns to normal; nevertheless, acute pancreatitis may recur after a period of full recovery.

In contrast, with chronic pancreatitis the pancreatic tissue never returns to its normal state and the sufferer has ongoing illness and continued symptoms. It may be difficult in the first instance to distinguish between a case of acute pancreatitis and the first manifestations of chronic pancreatitis.

What causes pancreatitis?

Most cases (about 80%) of acute pancreatitis are caused by either gallstones or excessive alcohol intake. In about 10% of cases the cause is unknown (though probably related to barely detectable, tiny gallstones or 'sludge'). There are many other conditions that are associated with acute pancreatitis, including various prescription drugs, cardiac or major abdominal surgery, trauma, peptic ulcer disease, infections, and raised blood calcium or lipid levels. Each year 1-2 people per 100,000 develop acute pancreatitis in the UK, but the incidence in the USA is reportedly much higher (20 people per 100,000 per year). For unknown reasons, the various causes of acute pancreatitis result in 'autodigestion' of the pancreas, as its enzymes are activated within the organ itself. Other enzymes are released into the circulation, which may cause more general effects away from the pancreas, including collapse of the blood circulatory system, respiratory (breathing) problems and kidney insufficiency.

 Chronic pancreatitis is caused by excessive alcohol use in 80-90% of cases in the Western world. (In tropical Africa or Asia malnutrition with cassava [tapioca] use is the major cause.) Most people with chronic pancreatitis have been drinking heavily for more than 10 years before the symptoms develop. Chronic exposure to fumes such as diesel, acetone and kerosene has also been implicated as a cause. The annual incidence is reported as 1 person per 100,000 in the UK and about 8 people per 100,000 in the USA, typically in men aged 40-50 years. With chronic pancreatitis, the inflammation within the pancreas does not recover, the pancreas develops irreversible structural changes, and its normal functions are permanently impaired.

 What are the symptoms of pancreatitis?

In both acute and chronic pancreatitis, the cardinal symptom is upper abdominal pain. Typically the pain is central, continuous, 'boring' in nature, and radiates through to the back. It is often worse when lying down, and partly relieved by sitting forward. The pain usually builds up to a peak over half to one hour, and then remains steady for hours or days. There is usually associated nausea and vomiting, and the upper abdomen is often tender.

Pancreatitis associated with excessive alcohol usually occurs after an episode of binge drinking. In those without a history of alcohol abuse, the attack may occur after a large meal; in this case, the cause may well be gallstones, especially in women over 50.

There are often other symptoms associated with acute pancreatitis. Abdominal distension is common (as fluid leaks into the space behind the abdominal organs, causing them to protrude forward). Mild fever is usual. Patients tend to 'under-breathe', which can cause respiratory problems. In severe attacks there may be bruising around the navel or along the flanks.

In chronic pancreatitis, episodes of acute pancreatitis recur until the pain becomes persistent and severe. The pain is brought on by eating, so that sufferers often avoid food and may lose much weight. Eventually, symptoms develop that are related to the failure of normal pancreatic function. Steatorrhoea are bowel motions that are pale, loose, fatty, and offensive, caused by the lack of lipase with subsequent malabsorption of fat; they also contribute to further weight loss. Symptoms of diabetes mellitus develop in one-third of patients, because of the lack of insulin and glucagon.

How is pancreatitis diagnosed?

Acute pancreatitis must be suspected in patients with typical presenting symptoms. The pain is such that patients are typically referred to hospital, where various blood tests are performed to aid the diagnosis, (e.g. measurement of pancreatic enzymes(especially amylase), as these are released into the circulation during the inflammatory process).

An abdominal ultrasound is usually performed to identify any gallstones and to try and visualize the swollen pancreas (and any fluid collections it may contain); however, in at least 50% of people, the pancreas is not visible because of obesity and overlying bowel gas. If the diagnosis is uncertain, or in patients with moderate-to-severe pancreatitis, a CT scan of the abdomen is performed.

The early diagnosis of chronic pancreatitis is more difficult, as there are no reliable specific blood tests, and early structural changes may be difficult to detect on imaging studies. Consequently, the diagnosis is based on the symptoms, the history and by excluding other conditions. In those with more advanced disease, various radiological tests (such as ultrasound, CT, dye studies or plain x-rays) may reveal pancreatic structural abnormalities. The pancreas may be enlarged, contain fluid-filled cysts or stones, or show calcification, and the main duct may be dilated or have areas of narrowing.

How is pancreatitis treated?

Patients with acute pancreatitis generally require admission to hospital, where they are assessed as to the severity of their condition by the results of various blood tests, and treated supportively until the condition resolves. Those with mild acute pancreatitis (i.e. 80% of cases) are treated in a general ward. The patient is not allowed to eat or drink in order to rest the bowel, and receives intravenous fluids during this time; oral fluids are restarted once the abdominal pain and tenderness are settling. In many people the small bowel becomes inactive (known as ileus) during an episode of acute pancreatitis, and the 'nil by mouth' order must remain until it becomes active again. If the ileus persists for over 5-7 days, the patient may require tube feeding. A nasogastric tube may be required to control the nausea and vomiting. Pain control often requires narcotic drugs such as pethidine. Most patients with mild acute pancreatitis recover in 2-3 days.

If the initial assessment indicates that the patient is likely to develop severe acute pancreatitis, he/she should be admitted to a high dependency or intensive care unit and managed as for mild pancreatitis but with additional treatment. Because of the increased likelihood of various complications, there is close monitoring of various bodily systems. Kidney function is measured by urine output using a urinary catheter, and dialysis may be necessary if kidney failure develops. Supervision of the circulation may require the use of special intra-venous or intra-arterial catheters. Occasionally, patients develop respiratory failure, which necessitates the use of a ventilator. Those with severe disease caused by gallstones may proceed to early removal of the stones by endoscopy (i.e. via the small intestine). Antibiotics are recommended, as severe disease may result in pancreatic necrosis (death of living tissue) with subsequent infection. If infected pancreatic necrosis does occur, then surgery is required to remove the necrotic tissue.

In chronic pancreatitis, treatment centres on abstinence from alcohol, long-term control of pain and management of the complications (diabetes mellitus and fat malabsorption). Various drugs are used to control pain; although non-steroidal anti-inflammatory agents are recommended initially, some patients may require stronger painkillers.

Micronutritional supplementation with antioxidants (selenium, beta-carotene, methionine, vitamins C and E) is helpful for some patients. A referral to a specialist pain clinic may be required. Steatorrhoea is managed by the use of pancreatic enzyme supplements; occasionally other drugs or a fat-restricted diet is necessary. Diabetes mellitus should be managed with appropriate treatment which may include diet,medications and/or possibly insulin. If all forms of conservative treatment fail to control symptoms, surgery to remove part of the pancreas may be indicated.

What are the complications of pancreatitis?

In mild acute pancreatitis there are few complications, although it is fatal in a minority of cases (<5% patients). Severe acute pancreatitis is fatal in 10-15% of cases, and 70% in those who develop infected pancreatic necrosis! Complications of severe acute pancreatitis are either generalised (e.g. lung or kidney failure, circulatory collapse) or localised (e.g. pancreatic necrosis, development of cysts within the pancreas, development of fistulas &endash; abnormal communications between the pancreas and the skin or other organs). These complications require treatment by surgery or endoscopy (i.e. from within the digestive tract).

As noted earlier, the main general complications of chronic pancreatitis are diabetes mellitus and fat malabsorption. Other localised complications include pancreatic cyst formation, narrowing of the duct that drains the gallbladder (resulting in jaundice), obstruction of the upper small intestine (rarely), or bleeding within the stomach and intestine. These complications generally require surgical or endoscopic treatment.

What is the long-term management of pancreatitis?

Most importantly in acute pancreatitis, the cause of the pancreatitis should be identified and treated if possible. Gallstones should be removed (a surgical procedure), ideally during the same hospital admission. The patient must abstain from alcohol for several months at least; those with alcoholism require management of that condition. A low-fat diet should be attempted, and narcotic pain-controlling medication should be gradually tapered to avoid dependence. If no cause was identified initially, a repeat ultrasound may be necessary to try and visualize any gallstones that may have been unseen during the acute episode. Patients with persisting pain or failure to regain weight should be re-evaluated for possible complications or the development of chronic pancreatitis.

By definition, patients with chronic pancreatitis require ongoing management, as explained above.

Bibliography:

Beckingham IJ, Bornman PC. Acute pancreatitis. British Medical Journal 2001;322:595-8

Bornman PC, Beckingham IJ. Chronic pancreatitis. British Medical Journal 2001;322:660-3

Mergener K, Baillie J. Acute pancreatitis. British Medical Journal 1998;316:44-8