Acute Pancreatitis

Question 1

Define acute pancreatitis

Answer 1

What: acute inflammation of the pancreas caused by release of activated pancreatic enzymes

Question 2

Causes of acute pancreatitis

Answer 2

• Idiopathic
• Gallstone (most common cause, 80% of cases): pathophysiology of obstruction is unknown
• Ethanol: prolonged alcohol abuse causes protein of pancreatic enzymes to precipitate within the small pancreatic ductules. These “plugs” can cause activation of pancreatic enzyme release and trigger acute pancreatitis
• Trauma (most common in children)
• Steroids
• Mumps (and other infections) and malignancy
• Autoimmune
• Scorpion stings and spider bites
• Hyperlipidaemia/hypercalcaemia (metabolic disorders)
• ERCP
Drugs: acetaminophen, NSAIDs, thiazide, sulfonamides

Question 3

4 mechanisms of pathophysiology in acute pancreatitis

Answer 3

1. Regardless of the aetiology of release of pancreatic enzyme release, which then leads to direct tissue damage and subsequently the activation of the complement system, inflammatory cascade and cytokines. This leads to oedema (mild), haemorrhage and necrosis (severe cases). The necrotic tissue can become infected
   
   2. Cytokines and activated enzymes that enter the peritoneal cavity cause chemical burn and 3rd spacing of fluid
   3. Those that enter the systemic circulation cause systemic inflammatory response that can lead to ARDS and respiratory distress
   4. Collection of enzyme rich pancreatic fluid and tissue debris form in and around the pancreas in some patients, this leads to either
      a. Spontaneous resolution
      b. Collection can become infected
      Collection becomes a pseudocyst that can haemorrhage, become infected or rupture

Question 4

Where is the pain normally located and where does it radiate?

Answer 4

Mid epigastrium (but also may be LUQ and RUQ or even non-localised)
Radiation directly through to the back

Question 5

When does the pain peak?

Answer 5

Peak pain is experienced a few hours into the illness

Question 6

If it is alcohol related when is the onset of pain?

Answer 6

If alcohol related: pain often develops 12-48 hours after inebriation

Question 7

If gallstone related when is the onset of pain?

Answer 7

If gallstone related: pain develops suddenly

Question 8

What is the most common associated feature?

Answer 8

Associated features: nausea and vomiting are common

Question 9

What are the aggravating and releivign factors?

Answer 9

• Relieving factors: sitting up and leaning forward

Aggravating factors: vigorous movement, coughing, deep breathing,

Question 10

What is the abdominal distension caused by?

Answer 10

Pancreatic inflammatory mass pushing up

Pancreatic duct disruption can cause ascites

Question 11

In severe cases haemorrhage into the retroperitoneum demonstrated by:

Answer 11

Grey Turner’s sign: ecchymoses in the flanks (have to turn over to see it)
Cullen’s sign: ecchymoses umbilical region

Question 12

DDx of acute pancreatitis

Answer 12

• Perforated gastric or duodenal ulcer
  
  • Mesenteric infarct
  • Strangulation of intestine
  • Dissecting aneurysm
  • Biliary colic
  • Appendicitis
  • Inferior wall MI
  • Diverticulitis
  • Haematoma of muscle wall or spleen

Question 13

What bloods are ordered and what would they show?

Answer 13

1. Lipase: more specific for acute pancreatitis as it is the sole source
   
   2. Amylase: 3x upper limit indicates acute pancreatitis. Peak usually at 24 hours of the onset of symptoms and rapidly returns to normal (3-7 days). Therefore if amylase levels are persistently high, then it may indicate the development of complications
   3. Hyperglycaemia
   4. Abnormal LFTs
   5. Hypocalcaemia: due to formation of Ca soaps secondary to excess generation of free fatty acids especially pancreatic lipase
   6. Increase WCC if infection

Question 14

What would be seen on AXR?

Answer 14

○ Calcifications within pancreatic ducts to indicate prior inflammation (chronic pancreatitis)
○ Calcified gallstones
Localised ileus LUQ or central abdo

Question 15

Why would we use an Abdo US?

Answer 15

Abdo US: to look for pancreatic oedema, gallstones or dilation of the common bile duct

Question 16

Why would we use CT with contrast?

Answer 16

CT with IV contrast: to identify necrosis, fluid collections, pseudocysts once pancreatitis has been diagnosed. This is recommended in severe pancreatitis or if complication ensues. IV contrast helps look for pancreatic necrosis

Question 17

If infection is suspected, what other Ix could we do?

Answer 17

If pancreatic infection suspected - percutaneous CT guided needle aspiration of the cyst or areas of fluid collection or necrosis can be gram stained and cultured

Question 18

List the complications of acute pancreatitis

Answer 18

• Pancreatic pseudocyts: internal pancreatic fistula
• Infection - all life threatening
○ Pancreatic abscess
○ Infected pancreatic pseudocyst
○ Infection of pancreatic necrosis
• Pancreatic ascites
• Haemorrhage “acute haemorrhage pancreatitis”
• Hypocalcaemia: as above, due to Ca soaps
• Shock
ARDS, respiratory distress

Question 19

What are the 5 key things in management of acute pancreatitis?

Answer 19

1. Fluid resuscitation * essential
   • IV hydration with crystalloids to maintain urinary output > 30mL/hour
   • Aggressive: 1 L bolus of crystalloid followed by continuous infusion rate of 3 mL / kg/ hour for first 24 hours
   • Maintain up to 6-8L/day with appropriate electrolytes
   • Consider blood transfusion in haemorrhagic pancreatitis
   • Inadequate fluid therapy increases the risk of pancreatic necrosis
   
   2. Catheterise patient to monitor urinary output in severe cases
   3. Fasting: patients should fast until acute inflammation subsides (this can last from days - weeks depending on severity). In severe cases, TPN should be initiated within the first few days to prevent undernutrition
   4. Analgesia and antiemetic:
      • Morphine 1-5mg IV every 4 hours PRN
      • Odansetron: 2-4 mg IV every 4 -6 hours when required
   5. Hypoxemia is treated with O2 mask or nasal prongs