Key Facts

Acute pancreatitis has a wide spectrum of severity. Early aggressive fluid resuscitation and identification of aetiology are the cornerstones of management.

Epidemiology

Incidence ~30-40 per 100,000/year in UK. Increasing incidence due to rising rates of gallstones and alcohol consumption. Male predominance for alcohol-related cases. Overall mortality ~5%; severe necrotising pancreatitis mortality ~15-30%.

Aetiology

GET SMASHED:

• Gallstones (~50%)
• Ethanol (~25%)
• Trauma, Steroids, Mumps, Autoimmune, Scorpion stings, Hyperlipidaemia/Hypothermia/Hypercalcaemia, ERCP, Drugs (azathioprine, valproate, mesalazine)
• Idiopathic ~10-20%

Pathophysiology

• Premature intrapancreatic activation of trypsinogen → trypsin → autodigestion of pancreatic tissue
• Release of inflammatory mediators → local and systemic inflammatory response
• Severe cases: Pancreatic necrosis, peripancreatic fluid collections, organ failure (lung, kidney, cardiovascular)
• Fat necrosis → hypocalcaemia (calcium saponification)

Classic Presentation

• Epigastric pain radiating straight through to the back
• Constant, severe, worsened by lying flat, relieved by sitting forward
• Nausea and vomiting
• Abdominal tenderness with guarding

Examination Findings

• Epigastric tenderness ± generalised peritonism
• Reduced bowel sounds (paralytic ileus)
• Tachycardia, hypotension, fever (in severe cases)
• Grey Turner's sign: Flank bruising (retroperitoneal haemorrhage) — rare, late sign
• Cullen's sign: Periumbilical bruising — rare, late sign

Red Flags (Severe Pancreatitis)

• Persistent organ failure >48 hours (Revised Atlanta Classification: Severe)
• CRP >150 at 48 hours
• Modified Glasgow score ≥3
• Evidence of pancreatic necrosis on CT
• Respiratory failure (ARDS)
• Shock requiring vasopressors

Bedside

• Observations: NEWS2
• ABG/VBG: PaO₂, lactate, glucose, calcium
• ECG: Exclude MI

Bloods

• Amylase/lipase: >3× ULN diagnostic (lipase preferred — more specific and sustained)
• FBC, CRP: WCC, CRP >150 at 48h suggests severe
• U&Es: Renal function, dehydration
• LFTs: ALT >3× ULN suggests gallstone aetiology
• Calcium: May be low (fat saponification — poor prognostic sign)
• Glucose: May be elevated (endocrine dysfunction)
• Triglycerides: If >10 mmol/L, consider as cause
• G&S/crossmatch: If haemorrhagic pancreatitis suspected

Imaging

• US abdomen: First-line — assess for gallstones, CBD dilatation
• CT abdomen with IV contrast: At 72-96 hours if severe (assess necrosis — Balthazar score); or earlier if diagnostic uncertainty
• MRCP: If CBD stones suspected and not seen on US

Initial Management

• Aggressive IV fluid resuscitation: Goal-directed (Ringer's lactate preferred); target UO >0.5 mL/kg/hr
• Analgesia: IV paracetamol + opioids (morphine or PCA); avoid NSAIDs (renal risk)
• NBM initially → early enteral nutrition (within 24-48 hours via NG/NJ tube if not tolerating orally) — reduces infection and mortality vs TPN
• VTE prophylaxis: LMWH
• Catheter: Monitor urine output
• Avoid prophylactic antibiotics — only if confirmed/suspected infected necrosis

Specific Management

Gallstone pancreatitis:

• ERCP within 72 hours if concurrent cholangitis or persistent biliary obstruction
• Cholecystectomy during same admission or within 2 weeks (reduces recurrence)

Necrotising pancreatitis:

• If infected necrosis (gas in necrosis on CT, positive FNA culture, clinical deterioration):
  • Step-up approach (PANTER trial): Percutaneous/endoscopic drainage → video-assisted retroperitoneal debridement (VARD) or endoscopic necrosectomy if drainage insufficient
  • Antibiotics: Meropenem 1g IV TDS or piperacillin-tazobactam

Referral Criteria

• All acute pancreatitis — surgical/gastroenterology team
• Severe pancreatitis — HDU/ICU for organ support
• Necrotising pancreatitis with infection — specialist hepatobiliary/pancreatic unit

• Mild (no organ failure): Mortality <1%; most resolve within 1 week
• Moderate (transient organ failure <48h): Mortality ~5%
• Severe (persistent organ failure >48h): Mortality ~15-30%
• Infected necrosis: Mortality ~20-30% (doubles compared to sterile necrosis)
• Gallstone pancreatitis recurrence: ~30-50% without cholecystectomy
• Long-term: Risk of chronic pancreatitis (~10% after severe episode), diabetes, exocrine insufficiency

Modified Glasgow (Imrie) Score

Revised Atlanta Classification (2012)