Pancreatitis Health Article

Definition

Pancreatitis is an inflammation of the pancreas, an organ that is important in digestion. Pancreatitis can be acute, beginning suddenly, usually with the patient recovering fully; or chronic, progressing slowly with permanent injury to the pancreas.

Description

The pancreas is located in the midline of the back of the abdomen, closely associated with the liver, stomach, and duodenum, the first part of the small intestine. The pancreas is considered a gland. A gland is an organ whose primary function is to produce chemicals that pass either into the main blood circulation (called an endocrine function), or pass into another organ (called an exocrine function). The pancreas is unusual because it has both endocrine and exocrine functions. Its endocrine function produces three hormones. Two of these hormones, insulin and glucagon, are central to the processing of sugars in the diet (carbohydrate metabolism or breakdown). The third hormone produced by the endocrine cells of the pancreas affects gastrointestinal functioning. This hormone is called vasoactive intestinal polypeptide (VIP). The pancreas's exocrine function produces a variety of digestive enzymes (trypsin, chymotrypsin, lipase, and amylase, among others). These enzymes are passed into the duodenum through a channel called the pancreatic duct. In the duodenum, the enzymes begin the process of breaking down a variety of food components, including, proteins, fats, and starches.

Acute pancreatitis occurs when the pancreas suddenly becomes inflamed but improves. Patients usually recover fully from the disease, and in almost 90% of cases, the symptoms disappear within about a week after treatment. The pancreas returns to its normal structure and functioning after healing from the illness. After an attack of acute pancreatitis, the tissue and cells of the pancreas typically return to normal. With chronic pancreatitis, damage to the pancreas occurs slowly over time. Symptoms may be persistent or sporadic, but the condition does not disappear and the pancreas is permanently impaired. Pancreatic tissue is damaged, and the tissue and cells function poorly.

Causes & symptoms

There are a number of causes of acute pancreatitis. The most common, however, are gallbladder disease and alcoholism. These two diseases are responsible for more than 80% of all hospitalizations for acute pancreatitis. Other factors in the development of pancreatitis include:

• certain drugs
• infections
• structural problems of the pancreatic duct and bile ducts (channels leading from the gallbladder to the duodenum)
• injury to the abdomen resulting in injury to the pancreas (including injuries occurring during surgery)
• abnormally high levels of circulating fats in the bloodstream
• malfunction of the parathyroid gland, with high blood levels of calcium
• complications from kidney transplants
• a hereditary tendency toward pancreatitis (recent advances in gene mapping have led to the discovery that a mutation in the gene responsible for cystic fibrosis is associated with a greatly increased risk of pancreatitis)

Pancreatitis caused by drugs accounts for about 5% of all cases. Some drugs that are definitely related to pancreatitis include:

• azathioprine, 6–mercaptopurine (Imuran)
• dideoxyinosine (Videx)
• estrogens (birth control pills)
• furosemide (Lasix)
• pentamidine (NebuPent)
• sulfonamides (Urobak, Azulfidine)
• tetracycline
• thiazide diuretics (Diuril, Enduron)
• valproic acid (Depakote)

Some drugs that are probably related to pancreatitis include:

• acetaminophen (Tylenol)
• angiotensin–converting enzyme (ACE) inhibitors (Capoten, Vasotec)
• erythromycin
• methyldopa (Aldomet)
• metronidazole (Flagyl, Protostat)
• nitrofurantoin (Furadantin, Furan)
• nonsteroidal anti–inflammatory drugs (NSAIDs) (Aleve, Naprosyn, Motrin)
• salicylates (aspirin)

All of these causes of pancreatitis seem to have a similar mechanism in common. Under normal circumstances, many of the extremely potent enzymes produced by the pancreas are not active until they enter the duodenum, in which contact with certain other chemicals allows them to function. In pancreatitis, these enzymes become prematurely activated and actually begin their digestive functions within the pancreas. The pancreas, in essence, begins to digest itself. This process is known as autodigestion. A cycle of inflammation begins, including swelling and loss of function. Digestion of the blood vessels in the pancreas results in bleeding. Other active pancreatic chemicals cause the blood vessels to become leaky, and fluid begins to leak out of the normal circulation into the abdominal cavity. The activated enzymes also gain access to the bloodstream through the eroded blood vessels, and begin circulating throughout the body.

Pain is a major symptom of pancreatitis. The pain is usually quite intense and steady, located in the upper right hand corner of the abdomen, and often described as "piercing" or "boring." This pain is also often felt all the way through to the patient's back. The patient's breathing may become quite shallow because deeper breathing tends to cause more pain. Patients usually find some relief of pain by sitting up and bending forward; this postural relief is characteristic of pancreatic pain. Nausea and vomiting, and abdominal swelling are all common, as well. A patient will often have a slight fever, with an increased heart rate and low blood pressure.

Classic signs of shock may appear in more severely ill patients. Shock is a very serious syndrome that occurs when the volume (quantity) of fluid in the blood is very low. In shock, a patient's arms and legs become extremely cold, the blood pressure drops dangerously low, the heart rate is quite fast, and the patient may begin to experience changes in mental status.

In very severe cases of pancreatitis (called necrotizing pancreatitis) the pancreatic tissue begins to die and bleeding increases. Due to the bleeding into the abdomen, two distinctive signs may be noted in patients with necrotizing pancreatitis. Turner's sign is a reddish purple or greenish brown color in the flank area (the area between the ribs and the hip bone). Cullen's sign is the appearance of a bluish color around the navel.

Some of the complications of pancreatitis are due to shock. When shock occurs, all of the body's major organs are deprived of blood and the oxygen it carries, resulting in damage. Kidney, respiratory, and heart failure are serious risks of shock. The pancreatic enzymes that have begun circulating throughout the body (as well as various poisons created by the abnormal digestion of the pancreas by those enzymes) have severe effects on the major body systems. Any number of complications can occur, including damage to the heart, lungs, kidneys, lining of the gastrointestinal tract, liver, eyes, bones, and skin. As the pancreatic enzymes work on blood vessels surrounding the pancreas, and even blood vessels located at a distance, the risk of blood clots increases. These blood clots complicate the situation by blocking blood flow in the vessels. When blood flow is blocked, the supply of oxygen is decreased to various organs and the organ can be damaged.

The pancreas may develop additional problems, even after the pancreatitis decreases. When the entire organ becomes swollen and suffers extensive cell death (pancreatic necrosis), the pancreas becomes extremely susceptible to serious infection. A local collection of pus (called a pancreatic abscess) may develop several weeks after the illness subsides, and may result in increased fever and a return of pain. Another late complication of pancreatitis, occurring several weeks after the illness begins, is called a pancreatic pseudocyst. This occurs when dead pancreatic tissue, blood, white blood cells, enzymes, and fluid that has leaked from the circulatory system accumulates. In an attempt to enclose and organize this abnormal accumulation, a kind of wall forms from the dead tissue and the growing scar tissue in the area. Pseudocysts cause additional abdominal pain by putting pressure on and displacing pancreatic tissue, resulting in more pancreatic damage. Pseudocysts also press on other nearby structures in the gastrointestinal tract, causing more disruption of function. Pseudocysts are life-threatening when they become infected (abscess) and rupture. Simple rupture of a pseudocyst causes death 14% of the time. Rupture complicated by bleeding causes death 60% of the time.

As the pancreatic tissue is increasingly destroyed in chronic pancreatitis, many digestive functions become disturbed. The quantity of hormones and enzymes normally produced by the pancreas begins to seriously decrease. Decreases in the production of enzymes result in the inability to appropriately digest food. Fat digestion, in particular, is impaired. A patient's stools become greasy as fats are passed out of the body. The inability to digest and use proteins results in smaller muscles (wasting) and weakness. The inability to digest and use the nutrients in food leads to malnutrition and a generally weakened condition. As the disease progresses, permanent injury to the pancreas can lead to diabetes.