Background Information

Aetiology

3 most common causes (in descending order of prevalence) are: ^[Ref]

• Gallstone (→ obstruction of pancreatic duct → backup of pancreatic secretions) – most common overall
• Alcohol use (alcohol metabolism generates toxic metabolites that cause premature activation of digestive enzymes within the pancreas)
• Hypertriglyceridaemia

 

I GET SMASHED is a commonly used acronym to remember the causes of acute pancreatitis: ^[Ref]

• I: idiopathic
• G: gallstones
• E: ethanol (alcohol)
• T: trauma
• S: steroids
• M: mumps
• A: autoimmune (e.g. IgG4-related disease)
• S: scorpion venom (rare..)
• H: hypertriglyceridaemia, hypercalcaemia, hypothermia
• E: ERCP (risk of acute pancreatitis after undergoing ERCP is ~10% in average patients, up to 30-50% in high-risk groups)
• D: drugs (key drugs: azathioprine, mesalazine, sodium valproate, thiazide diuretics, GLP-1 agonists)

Clinical Features

Symptoms

Typical presentation: ^[Ref]

• Sudden onset severe epigastric pain
  • Pain classically radiates to the back
  • Pain worsens when lying down and by eating
  • Pain improves with learning forward
• Fever
• Nausea and vomiting

Signs

Typical signs: ^[Ref]

• Signs of shock (e.g. tachycardia, hypotension etc.)
• Abdominal tenderness
• Abdominal distension
• Decreased bowel sounds

The following signs are rare: ^[Ref]

• Grey Turner’s sign: bruising of the flanks
• Cullen’s sign: periumbilical bruising

Complications

Local Complications

Pancreatic Necrosis (sterile)

• Diagnosis
  • Suspect if there are persistent or worsening symptoms ^[Ref]

• • Confirmation: cross-sectional imaging (CT/MRI with contrast) 3-4 days after pancreatitis onset
    • Findings: non-enhancing areas of pancreatic or peripancreatic tissue

 

• Management 
  • Most cases: conservative (interventions risk introducing infections)

Infected Pancreatic Necrosis

• Suspect if any of the following are present:
  • New or persistent fever
  • Bacteraemia
  • Worsening leukocytosis
  • Clinical deterioration or persistent unwellness
  • Cross-sectional imaging (CT or MRI) demonstrates gas within a pancreatic or peripancreatic collection (highly specific for infected necrosis)

 

• Management ^[Ref]
  • All patients: IV antibiotics
  • Additional: Debridement 
    • Preferred: minimally invasive (endoscopic transluminal / percutaneous catheter techniques)
    • Refractory cases: surgical debridement

Pancreatic Pseudocyst

• Definition: encapsulated collection of pancreatic fluid
  • Can occur in both acute/chronic pancreatitis, typically after ≥4 weeks of an acute attack ^[Ref]

 

• Clinical features:
  • Often asymptomatic 
  • Palpable abdominal mass
  • Pressure effects
    • Gastric outlet obstruction
    • Duodenal obstruction

 

• Diagnosis
  • Cross-sectional imaging (CT or MRI) demonstrating well-circumscribed, fluid-filled lesion with a defined wall

 

• Management 
  • Asymptomatic → typically conservative (as they often spontaneously resolve)
  • Complicated or symptomatic cysts → drainage
    • Preferred technique: endoscopic drainage (esp. if near stomach/duodenum)

Other Complications

• Biliary / duodenal obstruction (due to inflammation compressing adjacent structures)

 

• Pancreatic endocrine and exocrine insufficiency (although commoner in chronic pancreatitis)
  • Endocrine insufficiency → diabetes mellitus
  • Exocrine insufficiency → abdominal bloating, steatorrhoea, fat-soluble vitamin deficiency

Systemic Complications

Acute pancreatitis triggers a severe systemic inflammatory response that causes widespread organ injury

• ARDS
• AKI
• DIC
• Sepsis (often secondary to infected pancreatic necrosis)

Diagnosis

Diagnostic Criteria

At least 2 out of 3 of the following are diagnostic of acute pancreatitis (revised Atlanta classification):

• Abdominal pain suggestive of pancreatitis
• ↑ Serum amylase and/or lipase >3x the upper limit of normal
• CT / MRI findings consistent with acute pancreatitis

Diagnostic Tests

Blood Tests

Blood tests: ^[Ref1][Ref2]

• Serum amylase and/or lipase (to diagnose acute pancreatitis)
• LFT (cholestatic pattern suggests gallstone pancreatitis)
• Serum triglyceride and calcium (to look for hypertriglyceridaemia and hypercalcaemia)
• FBC, renal function, glucose
• IgG4 levels (if autoimmune pancreatitis is suspected)

Imaging

Choice of imaging: ^[Ref1][Ref2]

• 1st line: trans-abdominal ultrasound
  • Mainly to detect gallstones or biliary obstruction (NOT to diagnose acute pancreatitis)
  • The pancreas may appear normal in early disease
  • Findings suggestive of acute pancreatitis:
    • Enlarged, hypoechoic pancreas /peripancreatic fluid collections
    • Biliary pancreatitis: suggested by cholelithiasis, biliary sludge, stones within the CBD, or CBD dilation

• 2nd line: CT / MRI with contrast (reserved for diagnostic uncertainty, atypical presentation, assess complications)
  • Findings suggestive of acute pancreatitis (similar to US, but with higher sensitivity):
    • Diffuse/focal pancreatic enlargement
    • Heterogeneous or homogeneous enhancement
    • Peripancreatic fat stranding / fluid collections

Risk Assessment

The presence of the following features is associated with severe disease: ^[Ref]

• >55 y/o
• Hypocalcaemia (**hypercalcaemia can cause acute pancreatitis, but severe pancreatitis causes hypocalcaemia!)
• Hyperglycaemia (due to insulin deficiency)
• ↑ WBC
• ↑ LDH
• ↑ AST
• ↑ Urea (indicative of renal failure)
• ↓ PaO₂ (indicative of ARDS)

Management

Initial Management

Fluid resuscitation, supportive care & nutritional support are the 3 main cornerstones in the initial management of acute pancreatitis (regardless of the cause)

Fluid Resuscitation

Aggressive IV fluid resuscitation should be started immediately once the diagnosis is made:

• Fluid type: Isotonic fluids (e.g. Hartman’s solution, 0.9% saline)
• Goal-directed fluid resuscitation is recommended as part of ongoing fluid therapy to avoid fluid overload

Supportive care

Involving:

• Analgaesia
• Anti-emetics
• Electrolyte replacement

Nutritional Support

Key points regarding nutritional support:

• Do not routinely make patients NBM
• Early oral feeding is advised as soon as tolerated
• If unable to tolerate oral feeding → enteral feeding
• Only offer parenteral feeding if enteral feeding is not appropriate

Management of Underlying Cause

Underlying cause	Management
Gallstone (biliary) pancreatitis [Ref]	Same-admission cholecystectomy is recommended to prevent recurrence ERCP should NOT be performed routinely, only if there is concurrent cholangitis or persistent biliary obstruction
Alcohol-induced pancreatitis	Alcohol cessation is key (see Alcohol Use Disorders)
Hypertriglyceridaemia-induced pancreatitis [Ref]	Acute: IV insulin OR plasmapheresis in selected cases to rapidly lower triglyceride levels Long-term: dietary modification, lipid-lowering agents
Drug-induced pancreatitis	Withdrawal of the implicated medication is recommended if no alternative aetiology is identified

References