Chronic Pancreatitis
Chronic pancreatitis is long-standing inflammation of the pancreas that results in irreversible deterioration of pancreatic structure and function.
In the United States, the most common cause of chronic pancreatitis is alcohol abuse. Other causes include a hereditary predisposition and an obstruction of the pancreatic duct resulting from narrowing of the duct or pancreatic cancer. Rarely, an attack of severe acute pancreatitis makes the pancreatic duct so narrow that chronic pancreatitis results. In many cases, the cause of chronic pancreatitis is not known. In tropical countries (for example, India, Indonesia, and Nigeria), chronic pancreatitis of unknown cause occurs commonly in children and young adults.
Symptoms
Symptoms of chronic pancreatitis may be identical to those of acute pancreatitis and generally fall into two patterns. In one, a person has persistent midabdominal pain that varies in intensity. In this pattern, a complication of chronic pancreatitis, such as an inflammatory mass, a cyst, or even pancreatic cancer, is more likely. In the other, a person has intermittent flare-ups of pancreatitis with symptoms similar to those of mild to moderate acute pancreatitis; the pain sometimes is severe and lasts for many hours or several days. With either pattern, as chronic pancreatitis progresses, cells that secrete the digestive enzymes are slowly destroyed, so eventually the pain stops.
As the number of digestive enzymes decreases, food is inadequately absorbed (resulting in a condition called malabsorption), and the person may produce bulky, unusually foul-smelling stools. The stool is light-colored and greasy and may even contain oil droplets. The inadequate absorption of food also leads to weight loss. Eventually, the insulin-secreting cells of the pancreas may be destroyed, gradually leading to diabetes.
Diagnosis
A doctor suspects chronic pancreatitis because of a person's symptoms or history of acute pancreatitis flare-ups. Blood tests are less useful in diagnosing chronic pancreatitis than in diagnosing acute pancreatitis, but they may indicate elevated levels of amylase and lipase. Also, blood tests can be used to check the level of sugar (glucose) in the blood, which may be elevated.
Tests such as x-rays, ultrasound scans, and computed tomography (CT) scans are not routinely done for people with chronic pancreatitis. However, abdominal x-rays and ultrasound scans can be used to show stones in the pancreas. Endoscopic retrograde cholangiopancreatography (ERCP) (see Section 10, Chapter 134 and Section 10, Chapter 134) may reveal a dilated duct, narrowing of the duct, or stones in the duct. A CT scan may show these abnormalities as well as the size, shape, and texture of the pancreas. And unlike ERCP, a CT scan does not require the use of an endoscope.
People with chronic pancreatitis are at increased risk of pancreatic cancer. Worsening of symptoms, especially narrowing of the pancreatic duct, makes doctors suspect cancer. In such cases, a doctor is likely to order an ultrasound scan, CT scan, or endoscopic study.
Treatment
Treatment of repeated flare-ups of chronic pancreatitis is similar to that of acute pancreatitis. During a flare-up, avoiding alcohol is essential. Avoiding all food and receiving only intravenous fluids can rest the pancreas and intestine and may relieve a painful flare-up. In addition, opioid analgesics are sometimes needed to relieve the pain.
Later, eating four or five meals a day consisting of food low in fat and protein and high in carbohydrate may help reduce the frequency and intensity of the flare-ups. The person also must continue to avoid alcohol. If pain continues, a doctor searches for complications, such as an inflammatory mass in the head of the pancreas or a pseudocyst (a collection of pancreatic enzymes, fluid, and tissue debris resembling a cyst but without the usual lining found in other types of cysts). An inflammatory mass may require surgery; a pancreatic pseudocyst that causes pain as it expands may have to be drained (decompressed).
If the person has continuing pain and no complications, usually a doctor injects a combination of lidocaine and corticosteroids into the nerves from the pancreas to block pain impulses from reaching the brain. If this procedure fails, surgery may be performed. For instance, when the pancreatic duct is dilated, creating a bypass from the pancreas to the small intestine relieves the pain in about 60 to 80% of people. When the duct is not dilated, part of the pancreas may have to be removed. Removing part of the pancreas means that cells that produce insulin will be removed as well, and diabetes may develop.
For people who no longer produce adequate digestive enzymes, taking tablets or capsules of pancreatic enzyme extracts with meals can make the stool less greasy and improve food absorption, but these problems are rarely eliminated. If necessary, a liquid antacid, a histamine-2 (H2) blocker, or a proton pump inhibitor (drugs that reduce or prevent the production of stomach acid) may be taken with the pancreatic enzymes. With such treatment, the person usually gains some weight, has fewer daily bowel movements, has no more oil droplets in the stool, and generally feels better. If these measures are ineffective, the person can try decreasing fat intake. Supplements of the fat-soluble vitamins (A, D, E, and K) also may be needed.
Oral hypoglycemic drugs rarely can be used in the treatment of diabetes caused by chronic pancreatitis. Insulin is generally needed but can cause a problem, because these people also have decreased levels of glucagon, which is a hormone that acts to balance the effects of insulin. An excess of insulin in the bloodstream causes low sugar levels in the blood, which can result in a hypoglycemic coma (see Section 13, Chapter 166).
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