Acute pancreatitis complications and management · ICU Topics

Cinematic clinical photograph of a CT display showing walled-off pancreatic necrosis beside a patient on organ support, ICU setting, clinical-blue lighting, no text, no people — FigureInfected necrosis — drain first and delay surgery for four weeks; the step-up approach wins.

Local and systemic complications of severe acute pancreatitis — FigurePathophysiology of complications — SIRS, capillary leak, ARDS and AKI early; later infected necrosis, walled-off necrosis, haemorrhage and splenic-vein thrombosis.

Severity classification

Revised Atlanta Classification (click each)

Persistent organ failure (>48h)

Mortality ~30-50%

Persistent organ failure (>48h): respiratory (PaO2/FiO2 <300), cardiovascular (SBP <90 after fluids), renal (creatinine >170 µmol/L). Single or multiple organ failure. ICU admission required. High mortality (30-50% if multi-organ, >48h).

[3] [1] [4]

Management

Step-up approach for infected pancreatic necrosis — FigureManagement of infected necrosis — antibiotics with pancreatic penetration, delay intervention when possible, percutaneous/endoscopic drainage first, then minimally invasive debridement (PANTER step-up).

Severe pancreatitis management protocol

Aggressive IV fluid resuscitation

Lactated Ringer solution preferred (reduces SIRS and CRP vs saline — WATERFALL trial). Rate: 5-10 mL/kg/h for first 24-48h. Goal: urine output 0.5-1 mL/kg/h, haematocrit 35-44%. Monitor for fluid overload (can cause compartment syndrome). WATERFALL trial: aggressive (20 mL/kg bolus then 3 mL/kg/h) had MORE fluid overload than moderate (1.5 mL/kg/h) with no outcome benefit — avoid over-resuscitation. Reduce rate once goals met.

Early enteral nutrition (within 48h)

START EARLY. Old practice of NPO to "rest the pancreas" is WRONG and harmful. Enteral nutrition within 48h reduces: infection, complications, mortality, length of stay. NG or oral feeding both effective (meta-analyses show no advantage of nasojejunal over NG). Do NOT wait for bowel sounds or flatus. Pancreatitis is NOT a contraindication to feeding. TPN only if enteral feeding fails after 5-7 days (TPN increases infection, cost).

Pain control

Opioids: morphine, fentanyl, or oxycodone. Traditionally avoided morphine (sphincter of Oddi spasm — but evidence shows no significant effect). Use whatever controls pain. Patient-controlled analgesia (PCA) for severe pain. Avoid NSAIDs (bleeding risk if necrosis, AKI risk).

Do NOT give prophylactic antibiotics

Multiple RCTs and Cochrane meta-analyses: prophylactic antibiotics do NOT reduce infected necrosis or mortality. Increase: fungal infections, antibiotic resistance, C. difficile. Give antibiotics ONLY if: proven infection (positive cultures, infected necrosis on imaging), cholangitis, pneumonia, UTI. Cover: carbapenem (meropenem — good pancreatic penetration). ACG/IAP guidelines strongly recommend AGAINST prophylactic antibiotics.

Do NOT give prophylactic probiotics

PROPATRIA trial (Besselink, Lancet 2008): probiotic prophylaxis INCREASED mortality (16% vs 6%, p=0.01) — bowel ischaemia in 9 patients, some requiring surgery. NEVER give probiotics for predicted severe pancreatitis. This was a major change in practice.

ERCP if gallstone obstruction

Indications for urgent ERCP (<24-72h): cholangitis (fever + jaundice + RUQ pain — Charcot triad), biliary obstruction (persistent jaundice), suspected ampullary obstruction. NOT indicated for: gallstones without obstruction, mild pancreatitis without cholangitis. Cholecystectomy during same admission (after recovery) to prevent recurrence in mild cases; delayed in severe/necrotising until inflammation settles (~6 weeks).

Manage complications

ARDS: lung-protective ventilation (6 mL/kg, plateau <30). AKI: RRT if indicated. Shock: noradrenaline, careful fluids (fluid overload worsens outcome). Abdominal compartment syndrome: measure bladder pressure, decompress if >20 mmHg + organ failure. Hyperglycaemia: insulin infusion (target 6-10). Hypocalcaemia: only treat if symptomatic (tetany, seizures). Adjust magnesium first.

[1] [5] [4] [9]

Atlanta 2012 classification — morphology of local complications

The Revised Atlanta Classification (2012) standardises terminology based on timing (<4 weeks vs >4 weeks) and content (fluid vs necrotic). This is heavily examined — memorise the matrix. [1]

[3] [1]

Local complications — detail

Peripancreatic fluid collection (APFC) & pseudocyst

APFC (<4 weeks, fluid only): occurs in ~50% of acute pancreatitis. Usually resolves spontaneously within weeks. No intervention needed unless infected (rare). Do NOT drain sterile APFC.
Pseudocyst (>4 weeks, fluid only, encapsulated wall): forms when APFC persists and develops a fibrous/inflammatory wall. Most remain asymptomatic and resorb. Indications for drainage: infected, symptomatic (>6 cm and persistent pain, gastric outlet obstruction, biliary obstruction, rupture). Route: endoscopic (transgastric — preferred, lumen-apposing metal stent/LAMS), percutaneous, or surgical cystgastrostomy.

Pancreatic necrosis — sterile vs infected

Sterile necrosis: managed conservatively with supportive care. Do NOT debride sterile necrosis — even if extensive. Most patients recover without intervention. Antibiotics NOT indicated.
Infected necrosis: the dominant cause of late mortality in severe pancreatitis. Suspect with: clinical deterioration (fever, rising WBC/CRP, new sepsis/shock) after day 7-14. CT sign: gas within necrotic tissue (pathognomonic — requires no FNA). Fine needle aspiration (FNA) confirms (Gram stain/culture) but is NOT required if gas is present or clinical picture convincing.

Walled-off necrosis (WON)

WON (>4 weeks, necrotic content, encapsulated wall): the "mature" form of necrosis. Intervention is safer after wall maturation (~4 weeks) — reduces bleeding risk, defines plane for debridement. Symptoms: pain, early satiety, gastric outlet obstruction, biliary obstruction, infection. Endoscopic drainage with LAMS + direct endoscopic necrosectomy (DEN) is now first-line (TENSION trial).

Local complication — decision pathway

Day 1-4: initial phase

No CT needed unless diagnosis unclear or patient deteriorating. Early CT can UNDERESTIMATE necrosis (necrosis demarcates over 3-5 days). Manage supportively: fluids, analgesia, early EN. Measure severity scores.

Day 5-7: first CT if severe

Contrast-enhanced CT (CECT) if persistent organ failure, worsening pain, fever, or rising inflammatory markers. Assess: extent of necrosis (<30%, 30-50%, >50% — >30% predicts complications), peripancreatic fluid, vascular complications (splenic vein thrombosis, pseudoaneurysm).

Identify infection (day 7-14+)

Suspect infected necrosis if: fever, rising CRP/WBC, new/worsening sepsis, clinical deterioration. CT: gas in necrotic tissue = infected (pathognomonic). FNA optional. Sterile necrosis: continue conservative management. Infected: antibiotics + consider drainage.

Delay intervention if possible (≥4 weeks)

POINTER trial: postponed drainage (median 14 days later than immediate) gave similar complication rates, fewer fistulas, less pancreatic fistula surgery. Delay lets necrosis demarcate into WON — safer drainage/necrosectomy, less bleeding. If patient stable on antibiotics, WAIT.

Choose drainage route (step-up)

PANTER trial: percutaneous catheter drainage (PCD) first, with endoscopic/laparoscopic step-up if needed, superior to primary open necrosectomy. TENSION trial: endoscopic step-up superior to surgical step-up (fewer fistulas, shorter LOS). Route chosen by anatomy + local expertise. Endoscopic preferred when collection abuts stomach/duodenum.

Necrosectomy only if drainage insufficient

If drainage fails (ongoing sepsis, large solid burden): add minimally invasive necrosectomy. Endoscopic DEN via LAMS, percutaneous, or VARD (video-assisted retroperitoneal debridement). Open necrosectomy = LAST resort (highest mortality, fistula rate).

[6] [7] [8] [13]

Systemic complications — SIRS to MODS

Severe pancreatitis is a systemic inflammatory disease. Pancreatic injury releases pro-inflammatory mediators (cytokines IL-6, IL-8, TNF-α, phospholipase A2, trypsin, platelet-activating factor) that drive SIRS → distant organ dysfunction. [1]

Mechanism of distant organ injury

Acinar cell injury → systemic inflammation

Premature intracellular trypsinogen activation → acinar cell necrosis → release of damage-associated molecular patterns (DAMPs) and cytokines. Activated neutrophils/macrophages amplify inflammation (IL-6, IL-8, TNF-α). This systemic cytokine storm is the substrate for SIRS and MODS.

Endothelial dysfunction + capillary leak

Inflammatory mediators cause widespread endothelial injury → increased vascular permeability ("third spacing"), vasodilation, hypovolaemia, microvascular thrombosis. Contributes to: hypotension/shock, pulmonary oedema, abdominal compartment syndrome.

Organ-specific injury

Lungs: phospholipase A2 degrades surfactant + cytokine-mediated alveolar-capillary leak → ARDS. Kidneys: hypovolaemia + cytokine-induced tubular injury + intra-abdominal hypertension → AKI. Coagulation: tissue factor release + endothelial injury → DIC. Heart: myocardial depressant factor + cytokines → cardiomyopathy.

[3] [4] [3] [4] [1]

Severity scoring systems

Four scoring systems are examinable. Each has strengths/weaknesses — understand WHEN each applies and its cut-offs. [1]

[12] [11] [10] [3]

Ranson criteria — the 11 criteria (memorise)

At admission (5): age >55, WBC >16, glucose >11 mmol/L, AST >250, LDH >350. At 48h (6): Ca <2.0 mmol/L, haematocrit drop >10%, PaO2 <60 mmHg, base deficit >4, fluid sequestration >6 L, BUN rise >1.8 mmol/L. [1]

Mnemonic for non-gallstone Ranson: GA LAW (Glucose, Age, LDH, AST, WBC) at admission; at 48h: C HOBBS F (Calcium, Hematocrit, Oxygen, Base deficit, BUN, Fluid sequestration). [1]

BISAP score (5 components)

BUN >25 mg/dL (8.9 mmol/L), Impaired mental status (GCS <15), SIRS (≥2 criteria), Age >60, Pleural effusion. Score 1 point each; 3+ = severe. Validated in Wu et al 2008 (large population-based study). [1]

CT Severity Index (Balthazar)

Combines Balthazar grade (A-E: normal to extensive necrosis) with necrosis percentage (0/3/6/8 points for none/<30%/30-50%/>50%). Modified CTSI (Mortele) is simpler and correlates better with outcome. CTSI >7 = severe.

Infected necrosis — step-up approach

The step-up approach revolutionised management of infected necrotising pancreatitis. Before 2010, primary open necrosectomy was standard (mortality 20-40%). The PANTER and TENSION trials established that drain first, debride only if needed reduces morbidity and mortality. [1]

Infected necrosis management (step-up approach)

Diagnose infection

Clinical deterioration (fever, rising WBC/CRP, new sepsis) + CT findings (gas in necrotic tissue = pathognomonic, rim enhancement). Fine needle aspiration (FNA) can confirm but is NOT necessary if gas present or clinical picture convincing. Sterile necrosis does NOT require antibiotics or drainage.

Antibiotics

Broad-spectrum with good pancreatic penetration: carbapenem (meropenem 1g IV TDS), OR piperacillin-tazobactam 4.5g IV TDS, OR quinolone (ciprofloxacin) + metronidazole. Carbapenems achieve highest pancreatic tissue levels. De-escalate once cultures available. Continue until infection controlled + source managed. Antifungal prophylaxis NOT routine (CONSORT/Addenbrooke's studies show fluconazole does not reduce fungal infection).

Drain first (percutaneous or endoscopic)

Percutaneous catheter drainage (PCD, CT/US-guided) or endoscopic transluminal drainage (via stomach/duodenum using LAMS). PANTER trial: drain-first step-up approach superior to primary open surgery — fewer major complications/deaths (35% vs 69%), fewer fistulas, lower cost. ~35% of patients need ONLY drainage (no further intervention). Delay intervention for at least 4 weeks if haemodynamically stable (POINTER trial).

Step-up to necrosectomy if drainage insufficient

If drainage alone insufficient (ongoing sepsis, large necrotic burden): add necrosectomy. Minimally invasive routes: endoscopic DEN (via LAMS), percutaneous (VARD — video-assisted retroperitoneal debridement). TENSION trial: endoscopic step-up superior to surgical step-up (lower fistula rate, shorter LOS). Open necrosectomy = LAST resort (highest mortality, fistula, diabetes, exocrine insufficiency).

Timing — delay 4 weeks if possible

POINTER trial (2024): immediate vs postponed (median 14 days) drainage. Postponed group had similar complications, fewer pancreatic fistulas, less pancreatic surgery. Delay lets necrosis demarcate into WON (defined wall) — safer drainage, less bleeding, fewer procedures. Indications for earlier (immediate) drainage: septic shock unresponsive to antibiotics, peritonitis, bowel ischaemia/perforation.

Pseudocyst management

Peripancreatic fluid collection: usually resolves spontaneously. Pseudocyst (mature wall, >4 weeks, pure fluid): observe unless symptomatic. Drain if: infected, >6 cm and persistent, causing symptoms (pain, gastric outlet obstruction, biliary obstruction). Drainage route: endoscopic (transgastric — preferred), percutaneous, or surgical cystgastrostomy.

[6] [7] [8] [13] [15]

Landmark trials

PANTER — Step-up vs open necrosectomy (NEJM 2010)

Multicentre RCT, 88 patients with necrotising pancreatitis + suspected infection. Step-up approach (PCD ± minimally invasive retroperitoneal necrosectomy) vs primary open necrosectomy.

Key finding

Primary endpoint (major complications/death): 35% (step-up) vs 69% (open). Step-up reduced: new-onset multi-organ failure (12% vs 40%), incisional hernias, new-onset diabetes. ~35% treated with drainage alone — no surgery needed.

[6]

TENSION — Endoscopic vs surgical step-up (Lancet 2018)

Multicentre RCT, 98 patients with infected necrotising pancreatitis. Endoscopic step-up (endoscopic transluminal drainage ± endoscopic necrosectomy, with percutaneous fallback) vs surgical step-up (PCD ± VARD).

Key finding

Primary endpoint (composite: major complications/death): not significantly different (43% endoscopic vs 45% surgical). BUT endoscopic group: significantly fewer pancreatic fistulas (5% vs 28%), shorter length of stay, fewer interventions.

[7]

POINTER — Immediate vs postponed drainage (Ann Surg 2024)

Multicentre RCT, 42 patients with infected necrotising pancreatitis. Immediate drainage vs postponed (antibiotics + wait until clinical deterioration or >4 weeks).

Key finding

Median postponement 14 days. No significant difference in composite endpoint (death/major complications). Postponed group: fewer pancreatic fistulas, fewer drainage-related complications, less pancreatic surgery. ~60% of postponed group eventually needed drainage.

[8]

WATERFALL — Aggressive vs moderate fluid resuscitation (NEJM 2022)

Multicentre RCT, 249 patients with acute pancreatitis. Aggressive (20 mL/kg bolus, then 3 mL/kg/h) vs moderate (1.5 mL/kg/h, bolus 10 mL/kg only if hypovolaemic) Lactated Ringer for 72-120h.

Key finding

Primary endpoint (MODS at 72h): no significant difference. Aggressive group had significantly MORE fluid overload (20.5% vs 6.3%, p=0.004). No difference in SIRS, ARDS, or death.

[5]

PROPATRIA — Probiotic prophylaxis (Lancet 2008)

Multicentre RCT, 298 patients with predicted severe acute pancreatitis. Probiotic (multispecies) vs placebo to prevent infectious complications.

Key finding

NO reduction in infectious complications. INCREASED mortality: 16% (probiotic) vs 6% (placebo, p=0.01). 9 patients in probiotic group developed bowel ischaemia (4 died), vs none in placebo.

[9]

Antibiotics — what to give and when

[1] [4] [15] [1]

Vascular and other complications

[3] [4]

SAQ — Infected pancreatic necrosis and the step-up approach

10 minutes · 10 marks

A 54-year-old man is day 14 in ICU with severe necrotising gallstone pancreatitis (gallstone aetiology; BISAP 4; APACHE II 14 at admission). He has been receiving NG feeding, moderate goal-directed lactated Ringer resuscitation and supportive care. Over 48 hours he develops spiking fevers (39.2 degrees C), new atrial fibrillation with rate 138, rising vasopressor requirement (noradrenaline 0.45 mcg/kg/min), lactate 3.6 mmol/L, WBC 21 and CRP 290 mg/L. Contrast-enhanced CT shows >50% pancreatic necrosis with new gas locules within the collection, partially encapsulated. He has not been on antibiotics.

[1]

SAQ — Abdominal compartment syndrome in severe acute pancreatitis

10 minutes · 10 marks

A 46-year-old woman is ICU day 5 with severe alcohol-related necrotising pancreatitis (APACHE II 16, BISAP 4, >50% necrosis on day-7 CT). Cumulative fluid balance is +9.4 L. Over 12 hours she becomes oliguric (12 mL/h despite frusemide), her plateau pressure has risen from 29 to 41 cmH2O at unchanged tidal volume (6 mL/kg), her lactate has risen from 1.4 to 3.6 mmol/L and she requires noradrenaline 0.4 mcg/kg/min for a MAP of 66. The abdomen is grossly distended and tense. Bladder pressure (instilled 25 mL saline, supine, end-expiratory) is 28 mmHg. Recent creatinine 215 micromol/L, PaO2/FiO2 180.

[1]

Clinical pearls

High-yield severe pancreatitis points for the CICM/FFICM/EDIC exam

Severity definition: persistent organ failure >48h = severe (Revised Atlanta Classification). Single most important exam concept.[3] }
Lactated Ringer preferred over saline (reduces SIRS/CRP — WATERFALL trial also showed MODERATE rate > aggressive).[5] }
Early enteral nutrition within 48h — reduces infection, complications, mortality. NG as good as NJ.[1] }
Do NOT give prophylactic antibiotics — no mortality benefit, increases resistance/fungal infections (Cochrane meta-analyses).[15] }
Do NOT give probiotics — PROPATRIA trial showed INCREASED mortality (bowel ischaemia).[9] }
Infected necrosis: drain first (step-up approach — PANTER trial). Delay surgery 4 weeks (POINTER trial).[6][8] }
Endoscopic > surgical step-up when feasible (TENSION trial — fewer fistulas, shorter LOS).[7] }
Gas in necrosis on CT = infected necrosis (pathognomonic) — no FNA needed.[3] }
ERCP: only for cholangitis or biliary obstruction (not routine for gallstone pancreatitis without obstruction).[1] }
APACHE II >8 at admission = severe. Ranson ≥3 (at 48h). BISAP ≥3 (within 24h).[12][11][10] }
Atlanta 2×2 matrix: timing (</>4 weeks) × content (fluid/necrotic). Pseudocyst = fluid + wall + >4wk. WON = necrotic + wall + >4wk.[3] }
True pseudocysts are UNCOMMON in severe pancreatitis — most ">4 week cysts" are walled-off necrosis (need necrosectomy, not simple drainage).[3] }
Sterile necrosis — manage conservatively, do NOT debride or give antibiotics.[4] }
ARDS mechanism: phospholipase A2 destroys surfactant + cytokine alveolar-capillary leak. Lung-protective ventilation.[4] }
Splenic vein thrombosis → left-sided portal HTN → isolated GASTRIC (fundal) varices. Splenectomy curative.[3] }
Abdominal compartment syndrome: bladder pressure >20 mmHg + organ failure. From capillary leak + fluids. Decompress.[4] }
Cholecystectomy: same admission for mild gallstone pancreatitis; delay ~6 weeks in severe/necrotising.[1] }
Hypertriglyceridaemia (TG >11.3 mmol/L / 1000 mg/dL): treat with insulin infusion, plasmapheresis. Avoid propofol (lipid).[1] }
Carbapenems achieve highest pancreatic tissue levels — drug of choice for infected necrosis.[15] }
Causes: gallstones (#1, ~40%), alcohol (#2, ~30%), hypertriglyceridaemia, ERCP, drugs (azathioprine, mesalazine, didanosine), trauma, mumps, autoimmune, scorpion sting (exotic but classic).[1] }
Lipase >3x ULN = diagnostic (more specific than amylase, remains elevated longer). Amylase normalises in 3-5 days.[1] }
Hypocalcaemia: common (saponification of fat), do NOT routinely treat unless symptomatic (tetany, seizures). Correct Mg first.[4] }
CT severity index (Balthazar): necrosis >30% predicts complications. Avoid early CT (<72h) — underestimates necrosis.[3] }
Open necrosectomy is a LAST resort — highest mortality (20-40%), fistulas, diabetes, exocrine insufficiency.[13] }
Long-term outcomes after severe pancreatitis: diabetes (20-40%), exocrine insufficiency (steatorrhoea), recurrence, quality-of-life impairment.[13] }

Red flags

Critical pancreatitis points

Do NOT give prophylactic antibiotics for pancreatitis — no mortality benefit, increases resistance & C. diff.[1][15] }
Do NOT give probiotics — PROPATRIA trial showed INCREASED mortality (bowel ischaemia).[9] }
Early enteral nutrition within 48h — do NOT keep NPO (increases infection). NG as good as NJ.[1] }
Infected necrosis: drain first (step-up approach), delay surgery 4 weeks for demarcation.[6][8] }
Persistent organ failure >48h = severe pancreatitis. ICU admission.[3] }
Gas in necrosis on CT = infected necrosis — no FNA required. Start antibiotics + plan drainage.[3] }
Abdominal compartment syndrome: bladder pressure >20 + new organ failure. Decompress.[4] }
Aggressive fluid resuscitation causes harm — WATERFALL: moderate (1.5 mL/kg/h) ≥ aggressive (fluid overload).[5] }
Splenic artery pseudoaneurysm / haemorrhagic pancreatitis: emergency — CT angiography + IR embolisation, NOT surgery.[3] }
Early CT (<72h) underestimates necrosis — only image if diagnosis unclear or patient deteriorating.[3] }
Propofol in hypertriglyceridaemic pancreatitis: avoid (lipid load worsens triglycerides). Use fentanyl/ketamine.[1] }
Cholecystectomy before discharge for mild gallstone pancreatitis (prevents recurrence — up to 25% in 6 weeks without).[1] }

Common exam questions

[1] [1] [1] [1]

Aetiology — comprehensive mnemonic

[1]

Disposition and follow-up

Post-ICU and discharge planning

Resolve acute episode

Symptoms settled, tolerating oral diet, inflammatory markers trending down, no ongoing organ failure. Cholecystectomy before discharge if gallstone aetiology and mild-moderate episode.

Address local complications

Pseudocysts/WON: arrange outpatient follow-up imaging. Most resorb; persistent symptomatic collections need elective drainage. Pancreatic duct disruption/fistula: ERCP ± stenting.

Screen for long-term sequelae

Diabetes (HbA1c at 3 months), exocrine insufficiency (faecal elastase — enzyme replacement if low), recurrent symptoms. Counselling on alcohol cessation if applicable. Lipid-lowering (fibrate) for hypertriglyceridaemia.

Prevent recurrence

Gallstone: cholecystectomy. Alcohol: cessation programme. Hypertriglyceridaemia: fibrate ± omega-3, diabetic control. Drugs: cease offending agent. ERCP: avoid if possible. Autoimmune: corticosteroids (type 1). Tumour: surgical referral.

[1] [4]

References

[1]Tenner S, Vege SS, Sheth SG, Sauer BG. American College of Gastroenterology Guidelines: Management of Acute Pancreatitis Am J Gastroenterol, 2024.PMID 38857482
[2]International Association of Pancreatology. International Association of Pancreatology Revised Guidelines on Acute Pancreatitis 2025: Supported and Endorsed by the American Pancreatic Association, European Pancreatic Club, Indian Pancreas Club, and Japan Pancreas Society Pancreatology, 2025.PMID 40651900
[3]Banks PA, Bollen TL, Dervenis C, Gooszen HG, Johnson CD, Sarr MG, et al. Classification of acute pancreatitis--2012: revision of the Atlanta classification and definitions by international consensus Gut, 2013.PMID 23100216
[4]Working Group IAP/APA Acute Pancreatitis Guidelines. IAP/APA evidence-based guidelines for the management of acute pancreatitis Pancreatology, 2013.PMID 24054878
[5]de-Madaria E, Buxbaum JL, Maisonneuve P, Singh VK, Sáez-González A, Zhou Y, et al.; WATERFALL trial group. Aggressive or Moderate Fluid Resuscitation in Acute Pancreatitis N Engl J Med, 2022.PMID 36103415
[6]van Santvoort HC, Besselink MG, Bakker OJ, Hofker HS, Boermeester MA, Dejong CH, et al.; Dutch Pancreatitis Study Group. A step-up approach or open necrosectomy for necrotizing pancreatitis N Engl J Med, 2010.PMID 20410514
[7]van Brunschot S, van Grinsven J, van Santvoort HC, Bakker OJ, Besselink MG, Boermeester MA, et al.; TENSION trial group. Endoscopic or surgical step-up approach for infected necrotising pancreatitis: a multicentre randomised trial Lancet, 2018.PMID 29108721
[8]Van Veldhuisen CL, Sissingh NJ, Boxhoorn L, van Dijk SM, van Brunschot S, Belgers H, et al.; POINTER study group. Long-Term Outcome of Immediate Versus Postponed Intervention in Patients With Infected Necrotizing Pancreatitis (POINTER): Multicenter Randomized Trial Ann Surg, 2024.PMID 37450701
[9]Besselink MG, van Santvoort HC, Buskens E, Boermeester MA, van Goor H, Timmerman HM, et al.; PROPATRIA study group. Probiotic prophylaxis in predicted severe acute pancreatitis: a randomised, double-blind, placebo-controlled trial Lancet, 2008.PMID 18279948
[10]Wu BU, Johannes RS, Sun X, Conwell DL, Banks PA. The early prediction of mortality in acute pancreatitis: a large population-based study Gut, 2008.PMID 18519429
[11]Ranson JH, Rifkind KM, Roses DF, Fink SD, Eng K, Spencer FC. Objective early identification of severe acute pancreatitis Am J Gastroenterol, 1974.PMID 4835417
[12]Knaus WA, Draper EA, Wagner DP, Zimmerman JE. APACHE II: a severity of disease classification system Crit Care Med, 1985.PMID 3928249
[13]van Grinsven J, van Santvoort HC, Boermeester MA, Besselink MG, Dutch Pancreatitis Study Group. Superiority of Step-up Approach vs Open Necrosectomy in Long-term Follow-up of Patients With Necrotizing Pancreatitis Gastroenterology, 2019.PMID 30391468
[14]Moggia E, Koti R, Belgaumkar AP, Fazio F, et al. Pharmacological interventions for acute pancreatitis Cochrane Database Syst Rev, 2017.PMID 28431202
[15]Min L, He F, Bi B, Jiang S, Zhu L, Zhang Z. Assessment of Prophylactic Carbapenem Antibiotics Administration for Severe Acute Pancreatitis: An Updated Systematic Review and Meta-Analysis Digestion, 2022.PMID 35026770

[1]

Severity classification

Revised Atlanta Classification (click each)

Persistent organ failure (>48h)

Mortality ~30-50%

[3] [1] [4]

Management

Severe pancreatitis management protocol

Aggressive IV fluid resuscitation

Early enteral nutrition (within 48h)

Pain control

Do NOT give prophylactic antibiotics

Do NOT give prophylactic probiotics

ERCP if gallstone obstruction

Manage complications

[1] [5] [4] [9]

Atlanta 2012 classification — morphology of local complications

[3] [1]

Local complications — detail

Peripancreatic fluid collection (APFC) & pseudocyst

APFC (<4 weeks, fluid only): occurs in ~50% of acute pancreatitis. Usually resolves spontaneously within weeks. No intervention needed unless infected (rare). Do NOT drain sterile APFC.
Pseudocyst (>4 weeks, fluid only, encapsulated wall): forms when APFC persists and develops a fibrous/inflammatory wall. Most remain asymptomatic and resorb. Indications for drainage: infected, symptomatic (>6 cm and persistent pain, gastric outlet obstruction, biliary obstruction, rupture). Route: endoscopic (transgastric — preferred, lumen-apposing metal stent/LAMS), percutaneous, or surgical cystgastrostomy.

Pancreatic necrosis — sterile vs infected

Sterile necrosis: managed conservatively with supportive care. Do NOT debride sterile necrosis — even if extensive. Most patients recover without intervention. Antibiotics NOT indicated.
Infected necrosis: the dominant cause of late mortality in severe pancreatitis. Suspect with: clinical deterioration (fever, rising WBC/CRP, new sepsis/shock) after day 7-14. CT sign: gas within necrotic tissue (pathognomonic — requires no FNA). Fine needle aspiration (FNA) confirms (Gram stain/culture) but is NOT required if gas is present or clinical picture convincing.

Walled-off necrosis (WON)

WON (>4 weeks, necrotic content, encapsulated wall): the "mature" form of necrosis. Intervention is safer after wall maturation (~4 weeks) — reduces bleeding risk, defines plane for debridement. Symptoms: pain, early satiety, gastric outlet obstruction, biliary obstruction, infection. Endoscopic drainage with LAMS + direct endoscopic necrosectomy (DEN) is now first-line (TENSION trial).

Local complication — decision pathway

Day 1-4: initial phase

Day 5-7: first CT if severe

Identify infection (day 7-14+)

Delay intervention if possible (≥4 weeks)

Choose drainage route (step-up)

Necrosectomy only if drainage insufficient

[6] [7] [8] [13]

Systemic complications — SIRS to MODS

Mechanism of distant organ injury

Acinar cell injury → systemic inflammation

Endothelial dysfunction + capillary leak

Organ-specific injury

[3] [4] [3] [4] [1]

Severity scoring systems

Four scoring systems are examinable. Each has strengths/weaknesses — understand WHEN each applies and its cut-offs. [1]

[12] [11] [10] [3]

Ranson criteria — the 11 criteria (memorise)

Mnemonic for non-gallstone Ranson: GA LAW (Glucose, Age, LDH, AST, WBC) at admission; at 48h: C HOBBS F (Calcium, Hematocrit, Oxygen, Base deficit, BUN, Fluid sequestration). [1]

BISAP score (5 components)

CT Severity Index (Balthazar)

Infected necrosis — step-up approach

Infected necrosis management (step-up approach)

Diagnose infection

Antibiotics

Drain first (percutaneous or endoscopic)

Step-up to necrosectomy if drainage insufficient

Timing — delay 4 weeks if possible

Pseudocyst management

[6] [7] [8] [13] [15]

Landmark trials

PANTER — Step-up vs open necrosectomy (NEJM 2010)

Multicentre RCT, 88 patients with necrotising pancreatitis + suspected infection. Step-up approach (PCD ± minimally invasive retroperitoneal necrosectomy) vs primary open necrosectomy.

Key finding

[6]

TENSION — Endoscopic vs surgical step-up (Lancet 2018)

Key finding

[7]

POINTER — Immediate vs postponed drainage (Ann Surg 2024)

Multicentre RCT, 42 patients with infected necrotising pancreatitis. Immediate drainage vs postponed (antibiotics + wait until clinical deterioration or >4 weeks).

Key finding

[8]

WATERFALL — Aggressive vs moderate fluid resuscitation (NEJM 2022)

Multicentre RCT, 249 patients with acute pancreatitis. Aggressive (20 mL/kg bolus, then 3 mL/kg/h) vs moderate (1.5 mL/kg/h, bolus 10 mL/kg only if hypovolaemic) Lactated Ringer for 72-120h.

Key finding

Primary endpoint (MODS at 72h): no significant difference. Aggressive group had significantly MORE fluid overload (20.5% vs 6.3%, p=0.004). No difference in SIRS, ARDS, or death.

[5]

PROPATRIA — Probiotic prophylaxis (Lancet 2008)

Multicentre RCT, 298 patients with predicted severe acute pancreatitis. Probiotic (multispecies) vs placebo to prevent infectious complications.

Key finding

NO reduction in infectious complications. INCREASED mortality: 16% (probiotic) vs 6% (placebo, p=0.01). 9 patients in probiotic group developed bowel ischaemia (4 died), vs none in placebo.

[9]

Antibiotics — what to give and when

[1] [4] [15] [1]

Vascular and other complications

[3] [4]

SAQ — Infected pancreatic necrosis and the step-up approach

10 minutes · 10 marks

[1]

SAQ — Abdominal compartment syndrome in severe acute pancreatitis

10 minutes · 10 marks

[1]

Clinical pearls

High-yield severe pancreatitis points for the CICM/FFICM/EDIC exam

Severity definition: persistent organ failure >48h = severe (Revised Atlanta Classification). Single most important exam concept.[3] }
Lactated Ringer preferred over saline (reduces SIRS/CRP — WATERFALL trial also showed MODERATE rate > aggressive).[5] }
Early enteral nutrition within 48h — reduces infection, complications, mortality. NG as good as NJ.[1] }
Do NOT give prophylactic antibiotics — no mortality benefit, increases resistance/fungal infections (Cochrane meta-analyses).[15] }
Do NOT give probiotics — PROPATRIA trial showed INCREASED mortality (bowel ischaemia).[9] }
Infected necrosis: drain first (step-up approach — PANTER trial). Delay surgery 4 weeks (POINTER trial).[6][8] }
Endoscopic > surgical step-up when feasible (TENSION trial — fewer fistulas, shorter LOS).[7] }
Gas in necrosis on CT = infected necrosis (pathognomonic) — no FNA needed.[3] }
ERCP: only for cholangitis or biliary obstruction (not routine for gallstone pancreatitis without obstruction).[1] }
APACHE II >8 at admission = severe. Ranson ≥3 (at 48h). BISAP ≥3 (within 24h).[12][11][10] }
Atlanta 2×2 matrix: timing (</>4 weeks) × content (fluid/necrotic). Pseudocyst = fluid + wall + >4wk. WON = necrotic + wall + >4wk.[3] }
True pseudocysts are UNCOMMON in severe pancreatitis — most ">4 week cysts" are walled-off necrosis (need necrosectomy, not simple drainage).[3] }
Sterile necrosis — manage conservatively, do NOT debride or give antibiotics.[4] }
ARDS mechanism: phospholipase A2 destroys surfactant + cytokine alveolar-capillary leak. Lung-protective ventilation.[4] }
Splenic vein thrombosis → left-sided portal HTN → isolated GASTRIC (fundal) varices. Splenectomy curative.[3] }
Abdominal compartment syndrome: bladder pressure >20 mmHg + organ failure. From capillary leak + fluids. Decompress.[4] }
Cholecystectomy: same admission for mild gallstone pancreatitis; delay ~6 weeks in severe/necrotising.[1] }
Hypertriglyceridaemia (TG >11.3 mmol/L / 1000 mg/dL): treat with insulin infusion, plasmapheresis. Avoid propofol (lipid).[1] }
Carbapenems achieve highest pancreatic tissue levels — drug of choice for infected necrosis.[15] }
Causes: gallstones (#1, ~40%), alcohol (#2, ~30%), hypertriglyceridaemia, ERCP, drugs (azathioprine, mesalazine, didanosine), trauma, mumps, autoimmune, scorpion sting (exotic but classic).[1] }
Lipase >3x ULN = diagnostic (more specific than amylase, remains elevated longer). Amylase normalises in 3-5 days.[1] }
Hypocalcaemia: common (saponification of fat), do NOT routinely treat unless symptomatic (tetany, seizures). Correct Mg first.[4] }
CT severity index (Balthazar): necrosis >30% predicts complications. Avoid early CT (<72h) — underestimates necrosis.[3] }
Open necrosectomy is a LAST resort — highest mortality (20-40%), fistulas, diabetes, exocrine insufficiency.[13] }
Long-term outcomes after severe pancreatitis: diabetes (20-40%), exocrine insufficiency (steatorrhoea), recurrence, quality-of-life impairment.[13] }

Red flags

Critical pancreatitis points

Do NOT give prophylactic antibiotics for pancreatitis — no mortality benefit, increases resistance & C. diff.[1][15] }
Do NOT give probiotics — PROPATRIA trial showed INCREASED mortality (bowel ischaemia).[9] }
Early enteral nutrition within 48h — do NOT keep NPO (increases infection). NG as good as NJ.[1] }
Infected necrosis: drain first (step-up approach), delay surgery 4 weeks for demarcation.[6][8] }
Persistent organ failure >48h = severe pancreatitis. ICU admission.[3] }
Gas in necrosis on CT = infected necrosis — no FNA required. Start antibiotics + plan drainage.[3] }
Abdominal compartment syndrome: bladder pressure >20 + new organ failure. Decompress.[4] }
Aggressive fluid resuscitation causes harm — WATERFALL: moderate (1.5 mL/kg/h) ≥ aggressive (fluid overload).[5] }
Splenic artery pseudoaneurysm / haemorrhagic pancreatitis: emergency — CT angiography + IR embolisation, NOT surgery.[3] }
Early CT (<72h) underestimates necrosis — only image if diagnosis unclear or patient deteriorating.[3] }
Propofol in hypertriglyceridaemic pancreatitis: avoid (lipid load worsens triglycerides). Use fentanyl/ketamine.[1] }
Cholecystectomy before discharge for mild gallstone pancreatitis (prevents recurrence — up to 25% in 6 weeks without).[1] }

Common exam questions

[1] [1] [1] [1]

Aetiology — comprehensive mnemonic

[1]

Disposition and follow-up

Post-ICU and discharge planning

Resolve acute episode

Symptoms settled, tolerating oral diet, inflammatory markers trending down, no ongoing organ failure. Cholecystectomy before discharge if gallstone aetiology and mild-moderate episode.

Address local complications

Pseudocysts/WON: arrange outpatient follow-up imaging. Most resorb; persistent symptomatic collections need elective drainage. Pancreatic duct disruption/fistula: ERCP ± stenting.

Screen for long-term sequelae

Prevent recurrence

[1] [4]

References

[1]Tenner S, Vege SS, Sheth SG, Sauer BG. American College of Gastroenterology Guidelines: Management of Acute Pancreatitis Am J Gastroenterol, 2024.PMID 38857482
[2]International Association of Pancreatology. International Association of Pancreatology Revised Guidelines on Acute Pancreatitis 2025: Supported and Endorsed by the American Pancreatic Association, European Pancreatic Club, Indian Pancreas Club, and Japan Pancreas Society Pancreatology, 2025.PMID 40651900
[3]Banks PA, Bollen TL, Dervenis C, Gooszen HG, Johnson CD, Sarr MG, et al. Classification of acute pancreatitis--2012: revision of the Atlanta classification and definitions by international consensus Gut, 2013.PMID 23100216
[4]Working Group IAP/APA Acute Pancreatitis Guidelines. IAP/APA evidence-based guidelines for the management of acute pancreatitis Pancreatology, 2013.PMID 24054878
[5]de-Madaria E, Buxbaum JL, Maisonneuve P, Singh VK, Sáez-González A, Zhou Y, et al.; WATERFALL trial group. Aggressive or Moderate Fluid Resuscitation in Acute Pancreatitis N Engl J Med, 2022.PMID 36103415
[6]van Santvoort HC, Besselink MG, Bakker OJ, Hofker HS, Boermeester MA, Dejong CH, et al.; Dutch Pancreatitis Study Group. A step-up approach or open necrosectomy for necrotizing pancreatitis N Engl J Med, 2010.PMID 20410514
[7]van Brunschot S, van Grinsven J, van Santvoort HC, Bakker OJ, Besselink MG, Boermeester MA, et al.; TENSION trial group. Endoscopic or surgical step-up approach for infected necrotising pancreatitis: a multicentre randomised trial Lancet, 2018.PMID 29108721
[8]Van Veldhuisen CL, Sissingh NJ, Boxhoorn L, van Dijk SM, van Brunschot S, Belgers H, et al.; POINTER study group. Long-Term Outcome of Immediate Versus Postponed Intervention in Patients With Infected Necrotizing Pancreatitis (POINTER): Multicenter Randomized Trial Ann Surg, 2024.PMID 37450701
[9]Besselink MG, van Santvoort HC, Buskens E, Boermeester MA, van Goor H, Timmerman HM, et al.; PROPATRIA study group. Probiotic prophylaxis in predicted severe acute pancreatitis: a randomised, double-blind, placebo-controlled trial Lancet, 2008.PMID 18279948
[10]Wu BU, Johannes RS, Sun X, Conwell DL, Banks PA. The early prediction of mortality in acute pancreatitis: a large population-based study Gut, 2008.PMID 18519429
[11]Ranson JH, Rifkind KM, Roses DF, Fink SD, Eng K, Spencer FC. Objective early identification of severe acute pancreatitis Am J Gastroenterol, 1974.PMID 4835417
[12]Knaus WA, Draper EA, Wagner DP, Zimmerman JE. APACHE II: a severity of disease classification system Crit Care Med, 1985.PMID 3928249
[13]van Grinsven J, van Santvoort HC, Boermeester MA, Besselink MG, Dutch Pancreatitis Study Group. Superiority of Step-up Approach vs Open Necrosectomy in Long-term Follow-up of Patients With Necrotizing Pancreatitis Gastroenterology, 2019.PMID 30391468
[14]Moggia E, Koti R, Belgaumkar AP, Fazio F, et al. Pharmacological interventions for acute pancreatitis Cochrane Database Syst Rev, 2017.PMID 28431202
[15]Min L, He F, Bi B, Jiang S, Zhu L, Zhang Z. Assessment of Prophylactic Carbapenem Antibiotics Administration for Severe Acute Pancreatitis: An Updated Systematic Review and Meta-Analysis Digestion, 2022.PMID 35026770

Your progress

Severity classification

Persistent organ failure (>48h)

Management

Aggressive IV fluid resuscitation

Early enteral nutrition (within 48h)

Pain control

Do NOT give prophylactic antibiotics

Do NOT give prophylactic probiotics

ERCP if gallstone obstruction

Manage complications

Atlanta 2012 classification — morphology of local complications

Local complications — detail

Peripancreatic fluid collection (APFC) & pseudocyst

Pancreatic necrosis — sterile vs infected

Walled-off necrosis (WON)

Day 1-4: initial phase

Day 5-7: first CT if severe

Identify infection (day 7-14+)

Delay intervention if possible (≥4 weeks)

Choose drainage route (step-up)

Necrosectomy only if drainage insufficient

Systemic complications — SIRS to MODS

Acinar cell injury → systemic inflammation

Endothelial dysfunction + capillary leak

Organ-specific injury

Severity scoring systems

Ranson criteria — the 11 criteria (memorise)

BISAP score (5 components)

CT Severity Index (Balthazar)

Infected necrosis — step-up approach

Diagnose infection

Antibiotics

Drain first (percutaneous or endoscopic)

Step-up to necrosectomy if drainage insufficient

Timing — delay 4 weeks if possible

Pseudocyst management

Landmark trials

PANTER — Step-up vs open necrosectomy (NEJM 2010)

TENSION — Endoscopic vs surgical step-up (Lancet 2018)

POINTER — Immediate vs postponed drainage (Ann Surg 2024)

WATERFALL — Aggressive vs moderate fluid resuscitation (NEJM 2022)

PROPATRIA — Probiotic prophylaxis (Lancet 2008)

Antibiotics — what to give and when

Vascular and other complications

SAQ — Infected pancreatic necrosis and the step-up approach

SAQ — Abdominal compartment syndrome in severe acute pancreatitis

Clinical pearls

Red flags

Common exam questions

Aetiology — comprehensive mnemonic

Disposition and follow-up

Resolve acute episode

Address local complications

Screen for long-term sequelae

Prevent recurrence

References

Your progress

Severity classification

Persistent organ failure (>48h)

Management

Aggressive IV fluid resuscitation

Early enteral nutrition (within 48h)

Pain control

Do NOT give prophylactic antibiotics

Do NOT give prophylactic probiotics

ERCP if gallstone obstruction

Manage complications

Atlanta 2012 classification — morphology of local complications

Local complications — detail

Peripancreatic fluid collection (APFC) & pseudocyst

Pancreatic necrosis — sterile vs infected

Walled-off necrosis (WON)

Day 1-4: initial phase

Day 5-7: first CT if severe

Identify infection (day 7-14+)

Delay intervention if possible (≥4 weeks)

Choose drainage route (step-up)

Necrosectomy only if drainage insufficient

Systemic complications — SIRS to MODS