Pancreatitis is a disease in which the pancreas becomes swollen and inflamed, and does not work properly. The enzymes which the pancreas normally produces to help digestion in the intestine can attack the pancreas itself. The two common types of pancreatitis are acute and chronic.
Chronic pancreatitis is different from acute pancreatitis. The inflammation and damage develop more slowly, and can become increasingly bad over time. The pancreas becomes scarred and loses its ability to make enough digestive enzymes and insulin. Thickening of the pancreatic juices may result in clogging of the ducts and from pancreatic stones (so called pancreatic calcification). These and damage to the ducts themselves (strictures) can result in aggravation of the pancreatitis due to obstruction.
Causes and risk factors
Most cases of chronic pancreatitis are associated with longstanding heavy use of alcohol. However, chronic pancreatitis can also result from obstruction to the pancreatic ducts (by tumor or anatomical variation), and in other diseases such as cystic fibrosis, hemochromatosis (too much iron in the body). In familial pancreatitis, the problem occurs in many members of the family, and may start to cause attacks in childhood. A similar form of chronic pancreatitis occurs in tropical countries, often associated with severe malnutrition.
Presentation and clinical features
Most patients with chronic pancreatitis have pain in the upper abdomen, which may also be felt in the back. This can be very severe and continuous, but is more often intermittent, and occurs in attacks, which are usually not sufficiently severe to require immediate treatment in hospital. A few patients with chronic pancreatitis never have pain.
Lack of enzymes due to pancreatic damage results in poor digestion and absorption of food, especially fats. Thus, weight loss is characteristic of chronic pancreatitis. Patients may notice bulky smelly bowel movements due to too much fat (steatorrhea). Occasionally, an "oil slick" can be seen on the toilet water. Loss of insulin production may result in diabetes.
Swelling and scarring of the pancreas may damage other local structures. If the bile duct is narrowed, the patient may develop jaundice. Inflammation of the large vein (splenic vein) behind the pancreas may cause increased pressure in veins elsewhere, and the development of varices in the upper stomach and lower esophagus; these can burst and cause severe bleeding.
Patients with chronic pancreatitis carry a slightly increased risk of developing cancer of the pancreas.
Recognition and workup
The diagnosis of chronic pancreatitis is obvious in an advanced case with typical features – upper abdominal pains with weight loss, steatorrhea and diabetes. However, all of these features are seen only when the disease has been present for many years. Most patients present with pain only. Similar pains can be caused by cancer of the pancreas (although this is not usually intermittent), stones in the gallbladder and bile duct (biliary colic), or severe types of gastric or duodenal ulcer. All of these conditions have to be considered and appropriate diagnostic tests applied.
The blood levels of amylase and lipase are usually not raised in patients with chronic pancreatitis (as opposed to acute pancreatitis) – because the pancreas may no longer make much amylase or lipase. Poor function of the pancreas can be revealed by tests for diabetes (glucose tolerance tests, blood insulin levels), or examination of the stools for too much fat (3 day collections of stools for "steatorrhea"). There are other tests of "pancreatic function," but they are not widely used. The most sensitive consists of placing a tube through the mouth into the duodenum near the pancreatic drainage orifice, so as to collect the juices (after stimulating the pancreas). The juices are analyzed for their content of bicarbonate and certain enzymes. Simpler versions of this test using test substances given by mouth and collecting blood or urine are less sensitive.
Chronic pancreatitis is confirmed by X-ray tests and other scans. Ultrasound and CT scans can show enlargement and irregularity of the pancreas, and areas of scarring. They also demonstrate when the duct system is enlarged (dilated), and contains stones. When these stones are full of calcium (calcified), they may show up on a simple X-ray of the abdomen. A newer scanning test is called MRCP (magnetic resonance cholangiopancreatography). This shows the tissues of the pancreas, but also the duct systems in more detail.
Endoscopic ultrasound is another technique used to detect more subtle and early changes of chronic pancreatitis. ERCP (endoscopic retrograde cholangiopancreatography) is widely used in the evaluation and management of patients with known or suspected chronic pancreatitis. The specialist examines the pancreatic opening into the duodenum (papilla of Vater), and injects dye into the duct systems. This will show any area of blockage, stone or duct irregularity. Juices can be collected from within the pancreas for laboratory analysis. Other specimens (i.e. cytology brushings) can be taken when there is any suspicion of cancer.
Patients with chronic pancreatitis are treated by (i) abstaining from alcohol, (ii) medicines for pain relief, (iii) nutritional support, and (iv) replacement (by mouth) of missing digestive enzymes. Patients are normally advised to maintain a diet low in fat (less than 40 gm per day) when steatorrhea is present. Pancreatic enzyme supplements need to be taken in high dosage and with meals (often with medicines to reduce gastric acid). These help to digest fat, and may also sometimes reduce the amount of pain.
Pain control can be a challenge in patients with severe longstanding chronic pancreatitis. Narcotic addiction is a risk. It is possible to block the nerves which come from the pancreas by injection treatments ("celiac plexus block"). However, the effect rarely lasts more than a few months.
Surgical treatment may be helpful in certain circumstances, particularly to relieve obstruction to the pancreatic duct (or bile duct) or to remove damaged or poorly drained pancreatic tissue. The most common operations are the Puestow and Whipple procedures, or a Distal Pancreatectomy. It is rarely appropriate to remove the whole pancreas (total pancreatectomy). Some patients with chronic pancreatitis have pseudocysts, which sometimes requires surgical drainage.
ERCP techniques have limited application in treatment of patients with chronic pancreatitis. Sometimes it is helpful to improve pancreatic drainage by sphincterotomy and/or balloon dilatation of the duct system, with removal of stones or placement of stents. This can help also when there is leakage of pancreatic fluids (pancreatic fistulas).
Fistulas means leakage of fluid from an internal organ to the skin. This happens when the juices cannot drain through the normal routes. In the case of pancreatic fistulas, this happens when the pancreatic duct is blocked, particularly after an injury to the pancreas or surgery to it. Many fistulas dry up spontaneously after a few weeks; this process can be speeded by injections of a drug (somatostatin, octreotide) which reduces the production of pancreatic juices. In many cases it is necessary to "unblock" the pancreas. This can be done surgically, or by various methods of ERCP.