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Acute Pancreatitis

Acute pancreatitis for doctors, medical student exams, finals, OSCEs and MRCP PACES

 

Definition of acute pancreatitis

  • Inflammation of the pancreas, ranging from mild, self-limiting disease to complete necrosis of the entire organ
  • By definition, acute pancreatitis occurs on the background of a normal pancreas and can return to normal on resolution
    • Unlike chronic pancreatitis, which has irreversible changes

 

Epidemiology of acute pancreatitis

  • About 300 cases per million per year
  • Of these, 20% are mild and resolve without serious complications

 

Causes of acute pancreatitis (IGETSMASHED mnemonic)

  •  I – Idiopathic (most common)
  • G – Gallstones
  • E – Ethanol
  • T – Trauma
  • S – Steroids
  • M – Mumps
  • A – Autoimmune (e.g. PAN)
  • S – Scorpion Venom: only the black Trinidadian scorpion (tityus trinitatis)
  • H – Hyperlipidaemia, Hypercalcaemia
  • E – ERCP
  • D – Drugs
    • Azathioprine, thiazides, valproate, asparaginase, allopurinol
  • Also pregnancy

Video covering acute pancreatitis from pathophysiology to prognosis

 

Presentations of acute pancreatitis

  • History
    • Presenting complaint
      • Pain
        • Severe epigastric pain, radiating through to the back
        • Pain worse on lying down and relieved sitting forward
      • Vomiting
    • Previous history
      • Recent excess alcohol intake
      • Previous gallstone disease or ERCP
      • Specific search for causes as above
    • Family history of gallstones gallstones
  • Examination
    • Observations
      • Tachycardia
      •  Fever
    •  Tenderness or acute abdominal signs
      • Abdominal/epigastric tenderness
      • Rigid abdomen
      • Reduced or absent bowel sounds
    • Jaundice (if associated biliary obstruction)
    •  If severe:
      • Shock
      • Periumbilical staining (Cullen’s sign); flank staining (Grey-Turner’s sign)

 

Differential diagnosis of acute pancreatitis

  • Any other cause of an acute abdomen
  • Remember rarer causes of abdominal pain e.g.:
    • Myocardial infarction or pericarditis
    • Aortic dissection
    • Pneumonia

 

Scoring systems for severity of acute pancreatitis

Glasgow criteria for predicting severity: PANCREAS mnemonic

  • PaO2 <8Kpa
  • Age < 55yrs
  • Neutrophils (WBC > 15)
  • Calcium <2mmol/L
  • Renal function (Urea > 16)
  • Enzymes (LDH > 600, AST > 200)
  • Albumin < 32g/L
  • Sugar > 10mmol/L

3 or more positive factors predicts a severe pancreatitis and the patient should be managed in an HDU/ITU setting.

 

Initial management of acute pancreatitis: Click here for current BSG guidance

  • Bloods
    • Amylase – often >1000 but CAN be normal initially (esp if acute on chronic)
    • Lipase – more sensitive and specific than amylase but less readily available as a test
    • FBC (for neutrophils), U&Es (assess renal function), LFTs (for albumin and transaminases/bilirubin), calcium (for severity scoring)
  • Arterial blood gas
    • For severity scoring, and lactate
    • Repeat ABG or VBG regularly initially to ensure improving
  • Intravenous fluids
    • Patients need prompt and adequate fluid resuscitation
    • Third space fluid losses can be huge so may require several litres stat
    • Catherise if unwell
  • Oxygen supplementation
    • Keep sats >94% (if no existing lung disease)
  • Analgesia
    • Patients usually require regular opiates
  • Feeding
    • If nutritional support is required then the enteral route should be the preferred option if this is tolerated

 

Further management of acute pancreatitis (click here for reference)

  • Thromboprophylaxis
    • All patients with pancreatitis should have thromboprophylaxis unless clearly contraindicated (check renal function, platelets and clotting prior to dosing heparin)
  • Antibiotics
    • Current evidence is not conclusive regarding prophylactic antibiotics to prevent infection of necrosis. Giving antibiotics is not standard practice in the UK
  • Antisecretory agents
    • There is no evidence to support the use of antisecretory agents in acute pancreatitis
  • CT abdomen
    • Current guidelines recommend this be done after 6-10 days if persisting signs of organ failure, ongoing sepsis or clinical deterioration
    • CT can be performed earlier if there remains significant diagnostic uncertainty
  • ERCP
    • Urgent therapeutic ERCP with sphincterotomy should be performed within 72 hours in patients with acute severe pancreatitis and evidence of jaundice/common bile duct dilatation/cholangitis
  • Surgical intervention
    • All patients with infected necrosis will require radiological or surgical drainage and/or surgical debridement

 

Complications of acute pancreatitis

  • Early
    • Shock
    • Acute kidney injury
    • Acute respiratory distress syndrome
    • DIC
    • Sepsis
    • Hypocalcaemia
    • Hyperglycaemia
    • Pancreatic necrosis
  • Late
    • Pancreatic necrosis
    • Pancreatic pseudocyst
    • Pancreatic fluid in lesser sac
      • Presents > 6 weeks later
      • Abdominal mass may be present
      • May need internal (via stomach) or external drainage
    • Abscess
    • Thrombosis
      • Commonly in splenic/gastroduodenal arteries
    • Fistulae

 

Prognosis of acute pancreatitis

  • This is a high mortality condition, especially for severe disease with an overall mortality of 12%
  • Infection of necrotic pancreatitis carries a 40% mortality.

 

Click here for medical student OSCE and PACES questions about Acute Pancreatitis

Common Acute Pancreatitis exam questions for medical students, finals, OSCEs and MRCP PACES

Click here to download free teaching notes on Acute Pancreatitis: Acute Pancreatitis

Perfect revision for medical students, finals, OSCEs and MRCP PACES