What is acute pancreatitis?
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 caused 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.
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"— which can develop into a collection of fluid and damaged pancreatic tissue called a "pseudocyst". If a pseudocyst becomes infected, it is called a pancreatic abscess.
Also, 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.
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.
What are the causes of acute pancreatitis?
The two most common causes of acute pancreatitis are:
- excessive consumption of alcohol
Gallstones and acute pancreatitis
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 and acute 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.
Other causes of acute pancreatitis
Other known causes of acute pancreatitis include:
- poor drainage of the pancreatic duct resulting from partial obstruction — causes of obstruction include small tumors, as well as 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.
- a severe blow or direct injury to the upper abdomen, often incurred during a vehicular accident, but occassionally the result of a complication from a medical test or treatment (such as ERCP or surgery)
- a complication of some medicines and/or when the blood contains too much calcium or fat (especially triglycerides).
Pancreatitis can also 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).
When the cause of pancreatitis cannot be determined, it is referred to as "idiopathic".
What are the symptoms of acute pancreatitis?
Common symptoms of acute pancreatitis can include:
- sudden severe upper abdominal pain (often referred to as epigastric pain)
- severe pain that might also be felt in the back
- nausea and vomiting
- fever and chills
- racing of the heart (also known as tachycardia)
Symptoms are often severe enough as to require immediate medical attention and usually admission to hospital for pain medicines (analgesics) and intravenous (IV) fluids.
Diagnosing acute pancreatitis
Typical acute pancreatitis is usually easy to recognize:
- pain is located in a specific area
- onset of pain is sudden
- degree of pain is such that a person seeks immediate medical assistance
- an increased number of white blood cells in the blood stream (which is normal with all types of inflammation)
- markedly elevated levels of amylase and sometimes lipase —two enzymes produced by the pancreas— can be found in the blood stream
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).
A couple of acute abdominal conditions that can mimic pancreatitis include:
- impacted gallstones (biliary colic)
- gastric perforation or duodenal ulcer
More rarely, a similar clinical presentation can result from sudden loss of the blood supply to the intestines (intestinal ischemia).
Treatment for acute pancreatitis
Inflammation in acute pancreatitis involves the whole pancreas, so diabetes can result (either temporary or permanent) due to damage to the parts which normally produce insulin, known as 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, the treatment plan may include attempts to remove the stone(s). This is usually first attempted by ERCP, but can also be done with a standard surgical operation.
Unfortunately, there is no specific treatment for pancreatitis. Treatment for acute pancreatitis is largely supportive, such as:
- adequate pain control
- replacement of fluids and nutrition (which has to be given through a vein)
- bowel rest to reduce the production of enzymes by the pancreas, thereby reducing swelling
Antibiotics are needed when an 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)
- 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 (such as heavy alcohol consumption and gallstones) to help prevent further attacks.
All 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, while others may require an open surgical operation.