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.
Acute pancreatitis is usually a sudden and severe illness when the pancreas rapidly becomes inflamed. Pancreas enzymes and various poisons (toxins) may enter the blood stream in an acute attack, and injure other organs such as the heart, lungs and kidneys. However, the pancreas can return to virtual normality if the cause of the attack is found and treated.
Causes of acute pancreatitis
The two most common causes are gallstones and an excessive consumption of alcohol. Gallstones commonly form in the gallbladder. However, if a stone moves into the bile duct (through the cystic duct), it can become impacted (stuck) at the exit into the duodenum (papilla of Vater). This exit hole is normally shared with the pancreatic duct, so that an impacted stone can block the pancreas – and cause pancreatitis.
Alcohol causes acute pancreatitis by direct poisoning of the gland. Patients (and pancreases) vary in their sensitivity to alcohol. There is no completely safe level of consumption, and yet many people drink heavily for years without ever developing pancreatitis (or other alcohol-related diseases such as liver and heart disease). We do know that women are more sensitive to alcohol than men, and most authorities recommend three or less drinks per day for men, and two for women. Once pancreatitis has occurred, alcohol should be avoided completely. Alcohol can aggravate pancreatitis even if it has originally been caused by something else.
Acute pancreatitis can also occur due to poor drainage of the pancreatic duct resulting from partial obstruction; causes of obstruction include small tumors, and scarring and spasm of the muscular sphincter (sphincter of Oddi). Some patients are born with unusual drainage systems (i.e. pancreas divisum), which can interefere with drainage.
The pancreas can become acutely inflamed as a result of direct injury, e.g. a severe blow to the upper abdomen during an accident. The pancreas may also become acutely inflamed after some medical tests, and treatments (i.e. ERCP and surgery).
Acute pancreatitis can occur rarely as a complication of some medicines, and when the blood contains too much calcium or fat (especially triglycerides). When the cause of pancreatitis cannot be determined, it is referred to as "idiopathic".
The types of people likely to develop pancreatitis are obvious from the list of causes.
Clinical features of acute pancreatitis
Patients present with sudden severe upper abdominal pain which may be felt also in the back. The pain is often associated with nausea and vomiting. The symptoms are so severe as to require immediate medical attention, and usually admission to hospital for pain medicines (analgesics) and intravenous (IV) fluids.
Mild forms of pancreatitis (so called edematous pancreatitis) may resolve quite quickly, within a few days, without residual damage to the pancreas or other organs. Unfortunately, some patients develop severe "hemorrhagic" pancreatitis. This means that much of the pancreatic tissue is destroyed, with severe inflammation and leakage of enzymes, fluids and poisons. The pancreas becomes very swollen, and slushy; this is called a "phlegmon". This may develop into a collection of fluid and damaged pancreatic tissue called a "pseudocyst". If a pseudocyst becomes infected, it is called a pancreatic abscess.
Recognition and management
Typical acute pancreatitis is usually easy to recognize. The clinical features (i.e. nature and site of the pain) are characteristic, and a simple blood test is confirmatory. One of the enzymes produced by the pancreas is called "amylase". In acute pancreatitis this enzyme spills into the blood stream, so that it's level is markedly elevated. Raised levels of other enzymes (i.e. lipase) can also be detected. Normal levels of amylase and lipase do not completely rule out pancreatitis, especially when the pancreas has been damaged beforehand (and therefore cannot produce much amylase or lipase). As with all types of inflammation, the number of white cells in the blood stream may be increased.
Other acute abdominal conditions which can mimic pancreatitis include impacted gallstones ("biliary colic"), and perforation (bursting) of a gastric or duodenal ulcer. More rarely, a similar clinical presentation can result from sudden loss of the blood supply to the intestines (intestinal ischemia).
Severe attacks of "hemorrhagic" pancreatitis result in lowered blood pressure and poor circulation to the skin and other organs. Kidney failure may occur, requiring articial treatment such as dialysis. Other poisons in the blood resulting from pancreatitis can damage the heart and lungs. Inflammation in acute pancreatitis involves the whole pancreas, so diabetes can result (temporary or permanent) due to damage to the parts which normally produce insulin (islets of Langerhans). Patients may need multidisciplinary care in an intensive care unit, including artificial ventilation and other forms of life support.
When gallstones cause a severe attack of acute pancreatitis (by passing down to block the bile duct and pancreatic duct orifice), the treatment plan may include attempts to remove the stone. This can be done with a standard surgical operation, but is now usually first attempted by ERCP.
Unfortunately there is not a specific treatment for pancreatitis (like an antibiotic). Treatment for acute pancreatitis is largely supportive – i.e. providing the patient with adequate pain control and replacement of fluids and nutrition (which has to be given through a vein). A tube is usually placed through the nose into the stomach to suck out the gastric juices. Antibiotics are needed when infection is detected in the pancreas or other organs. There are experimental medicines aimed at reducing the secretion of pancreatic poisons, and neutralizing their effects.
Patients may require treatment for local complications of pancreatitis, such as pseudocysts and abscesses. When pseudocysts cause continuing symptoms (such as pain or pressure on other organs) the fluid must be drained. This can be done by passing a tube through the abdominal wall (percutaneous cyst drainage), surgery (pseudocyst-gastrostomy), or an approach through ERCP (endoscopic cyst drainage). When these are performed, it is usually necessary to leave a tube behind for continuing drainage.
Recurrent acute pancreatitis
Most patients recover from acute attacks of pancreatitis with no residual complaints; tests of the pancreatic function (enzymes and insulin secretion) and structure (ultrasound and CT scans) may return completely to normal. However, it is very important to look carefully for causative factors – to prevent further attacks. Alcohol consumption should be avoided completely. Gallstones are usually easy to discover (by standard tests such as ultrasound scanning of the gallbladder). However, pancreatitis can be caused by tiny stones (sludge or crystals) which cannot be seen on standard X-ray tests and scans. They can be found by special techniques such as placing a tube into the duodenum (duodenal drainage) and stimulation of gallbladder contraction, or during an ERCP examination. When stones, sludge or crystals are found, the gallbladder should be (almost always) removed (cholecystectomy).
All other causes must be carefully sought and eliminated where possible. Blood tests will show when there is too much calcium or fat (triglyceride). The presence of some form of duct obstruction can often be suspected by scanning (ultrasound, CT or MRCP), because the duct may become larger (dilated). However, examination for obstruction is best done with ERCP, which can examine the drainage systems in detail, including measurements of muscular activity. Some causes of poor drainage can be treated during the ERCP examination by sphincterotomy or stenting; others may require open surgical operation.