Surgical Emergencies: Acute Pancreatitis

The pancreas sits at the back of the abdomen, and is responsible for producing both the hormones that control blood sugar, such as insulin, and small gut enzymes that digest food. The enzymes normally drain though a little duct which opens into the small gut a little downstream from the stomach – here the pancreatic duct joins with the duct system that drains the gallbladder¹ and liver. Acute pancreatitis is the inflammation of the pancreas, and most commonly occurs in overweight, middle-aged ladies and alcoholics. It should not be confused with chronic pancreatitis, which is the long-standing damage that sometimes follows, causing chronic pain.

What Causes It?

While common triggers include gallstones, excessive alcohol and traumatic injury of the pancreas, the exact cause is not always found. Acute pancreatitis occurs when damage to pancreatic tissue causes the release of gut enzymes into the space between cells – the pancreas effectively tries to digest itself, which is understandably rather unpleasant. Inflammatory cells then arrive and produce various chemicals that only add to the problem.

How Is It Diagnosed?

The main symptom is upper abdominal pain that spreads to the back, and which may be relieved a little by sitting forward. The pain can come on suddenly or gradually, and is often accompanied by nausea and vomiting. The individual may be very unwell with a fever, rapid heart rate, falling blood pressure and a rigid tummy. Bruising around the flanks or belly button can occur (Grey Turner's and Cullen's signs, respectively), but these are unusual signs that turn up quite late on.

The amount of the gut enzyme amylase in the bloodstream can be measured, and is found to be massively raised in acute pancreatitis. Other blood tests will also indicate whether the cause is likely to be something as important as pancreatitis.

Mild versus Severe

Mild pancreatitis tends to be self-limiting, affecting only the pancreas with no complications. It is still, however, quite unpleasant and may recur if the underlying cause is not removed.

Severe pancreatitis occurs when the degree of inflammation produces complications, affecting either the pancreas itself or other organs:

• Death of the pancreatic tissue (necrosis) may occur.
• A collection of pus, or abscess, may develop within the pancreas, or the inflammation may damage nearby sections of gut or blood vessels.
• High blood sugar, and potentially diabetes mellitus, will occur if the pancreas is unable to produce enough insulin.
• Low blood calcium levels may occur, leading to muscle spasm and reduced conscious level if untreated.
• Inflammation of the lungs leads to poor exchange of oxygen between inhaled air and the bloodstream. This is referred to as Acute Respiratory Distress Syndome (ARDS) and can require artificial ventilation to support the lungs.
• Inflammatory chemicals in the blood stream can cause rapid clotting, using up all the blood's clotting materials in a reaction known as Disseminated Intravascular Coagulation (DIC).
• Other organs may be affected, leading to Multiple Organ Dysfunction Syndrome.

Severe pancreatitis is potentially life-threatening, and patients with severe disease should ideally be cared for on a high-dependency or intensive care unit. Scores such as the Glasgow Criteria or Ranson's Criteria can be used to determine the likely severity of the disease based on various markers. To demonstrate, here's the Glasgow Criteria:

• PaO2 < 60mmHg – a low blood oxygen level may occur due to degrees of lung inflammation.
• Age > 55 – older patients are more likely to suffer from severe pancreatitis.
• Neutrophils (WBC > 15x10^9) – a higher level of inflammatory cells in the bloodstream can indicate severe disease.
• Calcium < 2 mmols/L – as mentioned, pancreatitis can cause low blood calcium, particularly in severe cases.
• Renal (urea > 16 mmols/L) – the kidneys remove urea from the blood, and a rising urea indicates problems.
• Enzymes (LDH >600) – raised liver enzymes indicate underlying gallstone disease or liver involvement.
• Albumin – severe pancreatitis can cause leaking of albumin (the most common protein in the blood) out of the bloodstream.
• Sugar – as mentioned, failure of the pancreas to produce insulin will cause a rise in blood sugar.

Score 0-2: Likely mild pancreatitis.
Score >2: Likely severe pancreatitis.

Treatment

As the inflammation of the pancreas will cause leakage of fluid out of the bloodstream into the tissues, fluid management is very important. Early on in the treatment of pancreatitis, it is normal to have a cannula (bendy piece of plastic) inserted into a large vein and plenty of intravenous fluids given. The doctor will send off blood for the above tests, and ask the nurses to keep a close eye on input and output of fluids – this often necessitates a catheter (a tube inserted up into the bladder to drain urine). As if this were not enough, a tube should also be inserted into the stomach, via the nose (hence a 'nasogastric' tube), to drain the contents – this relieves any pressure on the gut and pancreas below. It is normal to restrict the individual to clear fluids only by mouth, at least until things start to improve. Antibiotics are given mostly in severe cases, whereas pain relief is important in every case of pancreatitis.

Once the initial treatment has been started, the individual can be sent for scans of the gallbladder, drainage ducts and pancreas, to look for gallstones and for complications of pancreatitis.

In severe pancreatitis where the pancreatic tissue has died, it can become necessary to remove the dead tissue. This is known as a necrosectomy. If a collection of pus (abscess) forms, this should ideally be drained. If enough of the pancreas is damaged, the individual may need long-term replacement of insulin and gut enzymes.

If the underlying cause is gallstones, these need sorting out as soon as possible. This can often be done using a telescope passed down into the stomach to reach the biliary duct – this is known as endoscopic retrograde cholangiopancreatography (ERCP), and can be used to treat gallstone disease and widen the entrance of the drainage ducts. Surgery to remove the gallbladder should be performed as soon as practical, although sometimes this must be delayed to allow inflammation to settle.

Summary

Acute pancreatitis is due to inflammation of an important gland, usually due to gallstones, alcoholism or trauma. It requires prompt treatment with intravenous fluids, and is investigated and closely monitored by the surgical team as it can produce dangerous complications if severe.

Please Note: h2g2 is not a definitive medical resource. If you have any health concerns, you must always seek advice from your local GP. You can also visit NHS Direct.

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¹ The gallbladder concentrates bile, which is required for fat digestion. This bile can form into lumps known as gallstones.