The pancreas

This may be mild or severe. Mild acute pancreatitis causes some swelling of the pancreas, but there is minimal upset to the gland and it recovers easily.

Severe acute pancreatitis on the other hand is associated with necrosis (death) of a part of the pancreas. The gland may cease to work, at least for the time being. Severe acute pancreatitis can cause local complications such as infection, pseudocyst formation (a collection of inflammatory fluid) or abscess formation (a collection of pus). It may also affect other organs of the body as part of a systemic inflammatory response.

In around 80% of patients with acute pancreatitis, the condition will settle rapidly. But 20% will develop complications.

The common causes are:

• Gallstones
• Alcohol excess
• Idiopathic (i.e. the cause is unclear)

Some rarer causes are:

• Certain viral infections such as Mumps and Coxsackie B
• Following trauma or major surgery
• After ERCP (an endoscopic procedure)
• Pancreatic cancer
• Certain drugs (azathioprine, asparaginases, steroids)
• A hyperactive parathyroid gland
• Hyperlipemia (raised serum lipid levels)
• Pancreas divisum (a congenital abnormality of the pancreatic ducts)

• Severe abdominal pain is the main symptom
• Vomiting may be present
• Jaundice is occasionally seen

The history and physical findings may suggest to the doctor that the patient has acute pancreatitis. Most patients will undergo several blood tests on arrival in the emergency room of a hospital with acute abdominal pain. An abdominal x-ray may be requested to rule out other conditions that can cause similar symptoms. If pancreatitis is suspected, a measurement of the serum amylase level is usually requested. If this is markedly raised, it points to the diagnosis of acute pancreatitis. But there are other causes for a high serum amylase level, and also, a normal serum amylase does not totally rule out pancreatitis.

Once the diagnosis of acute pancreatitis is made, usually the doctors will look at a set of factors to try and decide if the pancreatitis is mild or severe. These are called the
Glasgow criteria, and include:

• Age over 55 years
• pO₂ (plasma oxygen) level below 8
• Serum Albumin level below 32 g/l
• Serum Calcium level below 2 mmol/l
• White Blood Cell count over 15 x 109/l
• Serum LDH level over 600 u/l (LDH is an enzyme)
• Blood Glucose level over 10
• Blood Urea level over 16 (Urea is a waste product)

Within 48 hrs of admission, if 3 or more of these criteria are present, the patient is deemed to have severe acute pancreatitis. Of course, these criteria are not cast-iron, and it is possible that some patients with severe pancreatitis will not meet the criteria, and some will meet the criteria but not have severe pancreatitis. There are other predictive systems apart from the Glasgow criteria, such as the Ranson criteria or the APACHE 2 score.

Initial management of mild cases usually involves the following:

• Intravenous fluids
• Pain relief
• Close monitoring of the heart rate, blood pressure, respiration and urine output
• Oxygen may be given

Initial measures in patients thought to have severe acute pancreatitis include:

• Monitoring in a High Dependency or Intensive Care unit
• Aggressive intraveous fluid resuscitation
• Administering oxygen and monitoring the blood oxygen levels; the possible need for assisted ventilation should be kept in mind
• Close monitoring for kidney insufficiency
• Inotropic support if required (inotropes are drugs that stimulate the heart and bring up the blood pressure)
• Careful monitoring of the blood clotting process
• Monitoring the serum Calcium level as this may fall
• Early tube feeding via a naso-jejunal or naso-gastric tube should be considered
• Pain relief
• Antibiotics such as Cefuroxime or Imipenem may be given

In all patients with severe acute pancreatitis, an ultrasound scan of the abdomen should be considered within 24 hours of admission. If gallstones are seen on ultrasound, and the patient is thought to have severe acute pancreatitis due to gallstones, an ERCP should be considered within 48-72 hrs of admission. This is an endoscopic procedure (endoscopic retrograde cholagio-pancreatography) that allows the removal of gallstones lodged on the bile duct, and thus reduces the likelihood of biliary infection. Patients suspected of having already developed biliary infection (cholangitis) need urgent ERCP and clearance of the bile duct.

All patients with severe acute pancreatitis who do not resolve rapidly, should have a CT scan of the abdomen within 3-10 days. Usually some contrast material is injected into the veins at the time of the scan, and if parts of the pancreas do not take up the contrast, then it indicates that those parts of the pancreas are necrotic (dead).

Any severe inflammatory process within the body can trigger off a systemic inflammatory response that can then affect other organs, including the heart and the circulation, the lungs, the kidneys and the clotting process. Occasionally, severe acute pancreatitis can lead to single- or multi-organ failure. Such patients need management in an intensive care unit, and may require inotropic drugs to support the heart and the circulation, mechanical ventilation to support the lungs or haemofiltration (akin to dialysis) to support the kidneys.

After the first few days of the onset of the inflammation, local complications may show up in and around the pancreas. These include:

• Acute fluid collection around the pancreas (commonly seen and usually left alone for the body to absorb)
• Acute pseudocyst (a fluid collection that does not disappear and gradually gets walled off)
• Pancreatic necrosis (i.e. death of part of the pancreas). The dead or necrotic area may remain sterile (uninfected) and slowly get replaced by scar tissue, or it may become infected.
• Abscess formation (a collection of pus around the pancreas). Sometimes the term phlegmon is used to describe such an abscess.

Sterile pancreatic necrosis is best left alone. For infected pancreatic necrosis, or a pancreatic abscess, aspiration of some of the infected fluid or pus with a fine needle under ultrasound or CT guidance is usually the first step. Microbiological testing of the fluid can tell what bacteria are present in it.

After this, the treatment may involve placing a tube drain in the infected fluid to drain it to the exterior. If that does not suffice then an operation to remove the dead pancreatic tissue may be considered. This is called a Necrosectomy. The approach to the dead tissue may be through a cut (incision) in the front of the abdomen, or through one of the flanks, or even via a keyhole (laparoscopic) approach. After the dead tissue has been cut away, the wound may be left open with cloth packs inside, and another operation performed in 24-48 hours to check on progress. Or tube drains may be placed inside, with irrigation fluid run though them to wash away further pus that may form. Such operations carry a high element of risk. The patients are invariably very unwell and are nursed in an intensive care setting.

A pseudocyst is a collection of inflammatory fluid, surrounded by a lining of inflammatory (granulation) tissue. The term cyst refers to a collection of fluid and the prefix pseudo indicates that unlike a true cyst, it is not lined by a membrane (epithelium) that secretes the fluid. A pancreatic pseudocyst that has been present for less than 6 weeks has a good chance of healing spontaneously, and not developing complications. It may therefore be reasonable to wait and watch it for some time. On the other hand, one that has been present for over 12 weeks is unlikely to resolve spontaneously, and has a higher likelihood of developing complications. The complications that can develop include internal bleeding, rupture of the cyst, infection within the cyst leading to an abscess, development of a fistula (abnormal communication) between the cyst and a surrounding organ such as the bowel, and compression of a surrounding organ by an enlarging cyst.

CT scan showing a large pseudocyst in a young woman, several months after an attack of acute gallstone-induced pancreatitis

The indications for intervening may be listed as follows:

• Duration: the pseudocyst has been present for over 6 weeks
• Large size, with a diameter of over 6 cm (some would say 10 cm)
• The pseudocyst has a thick wall, seen on ultrasound or CT
• The pseudocyst is causing symptoms (usually pain)
• The pseudocyst has a communication with the pancreatic duct – this may be seen on ERCP
• The pseudocyst has developed in a setting of chronic pancreatitis
• One cannot distinguish it definitely from a malignant growth
• Complications have developed already

An ERCP may sometimes be performed before embarking on definitive treatment of a pseudocyst, to look for a channel between the cyst and the pancreatic duct. Distinction between a cystic tumour and a pseudocyst is made on the basis of the history, the appearance on CT and ultrasound, and by aspiration of the fluid, which can be tested for tumour cells and tumour marker substances such as CEA.

Simply drawing out the fluid with a needle (i.e. aspiration) is unlikely to cure a pseudocyst. Placing a drain into the cyst to drain the fluid to the exterior is also unlikely to succeed. The ideal treatment is to create a connection between the pseudocyst and the stomach or the bowel, so that the fluid forming within the pseudocyst can continuously drain into the gut. This causes the pseudocyst to gradually collapse and disappear. This kind of internal drainage is called a cyst-gastrostomy or cyst-jejunostomy. Traditionally this has been done by carrying out a surgical operation. That still remains the standard treatment, but some other options have now emerged. Nowadays, in some situations, surgeons may elect to do the operation by a keyhole approach (i.e. laparoscopically). An internal drainage procedure may also be carried out via the endoscope (endoscopic cyst-gastrostomy under endoscopic ultrasound guidance) or by approaching the pseudocyst under CT guidance through a puncture in the abdominal wall, and placing a tube connecting the pseudocyst cavity and the stomach. The efficacy of these newer techniques is yet to be fully established. For more information, you should consult your doctor.