Acute pancreatitis, start to finish.
Acute pancreatitis per ACG 2024 and IAP 2025: Revised Atlanta diagnosis and grading, etiology and ERCP, BISAP and SIRS, WATERFALL moderate fluids, feeding, necrosis timing, and hypertriglyceridemia care.
Reviewed October 2026 · verify against current guidelines
At the bedside — open the pancreatitis calculator: Revised Atlanta diagnosis check, BISAP, SIRS count, modified Marshall organ-failure scoring with the severity grade, a weight-based moderate fluid plan with checkpoints, and a hypertriglyceridemia mode with unit conversion. Scope: adults, per the 2024 ACG guideline, the 2025 IAP revised guidelines (endorsed by the APA, EPC, Indian Pancreas Club and Japan Pancreas Society), the 2012 Revised Atlanta classification and the WATERFALL trial. Where they differ, both positions are shown.
Acute pancreatitis · 1 of 6
Diagnose with two of three.
Revised Atlanta: any two make the diagnosis
| Pain | Acute upper abdominal pain consistent with pancreatitis: usually epigastric, constant, often radiating to the back. Dull, colicky or lower abdominal pain points elsewhere (ACG 2024). |
|---|---|
| Enzyme | Serum lipase or amylase at least 3 times the upper limit of normal (Revised Atlanta; ACG and IAP word it as more than 3 times). Prefer lipase: amylase alone is not reliable enough (ACG 2024). |
| Imaging | Features of acute pancreatic inflammation on contrast CT, MRI or ultrasound. |
The 3-times cutoff is a convention, not a law
In the Cochrane analysis cited by IAP 2025, lipase above 3 times normal had a sensitivity of 79% and a specificity of 89%. A level below the cutoff does not exclude pancreatitis, and a level above it can come from outside the pancreas. Without compatible pain, a high lipase does not predict pancreatitis (ACG 2024). Once the diagnosis is made, stop trending enzymes: they do not track severity, prognosis or readiness to eat or go home.
When to image
| Ultrasound, everyone | Transabdominal ultrasound for gallstones in every patient; repeat it if the first is inconclusive (ACG 2024; IAP 2025). |
|---|---|
| CT early, only if | The diagnosis is in doubt, for example to exclude perforation, ischemic bowel or obstruction. Admission CT for severity is not recommended (ACG 2024; IAP 2025). |
| CT later, if | No improvement after 48 to 72 hours, or clinical deterioration. For staging necrosis, CT is most informative at least 72 to 96 hours after symptom onset (IAP 2025). |
| MRI instead | Contrast allergy or renal insufficiency: non-gadolinium T2-weighted MRI shows necrosis. MRI is also better for duct stones and duct disruption (ACG 2024). See contrast nephropathy. |
Acute pancreatitis · 2 of 6
Name the cause before discharge.
Every admission (IAP 2025 good practice statement)
- History: prior attacks, known gallstones, alcohol, medications, known hypertriglyceridemia, trauma, recent ERCP, family history of pancreatic disease.
- Labs: liver tests, calcium and triglycerides on the first draw.
- Imaging: abdominal ultrasound of the gallbladder and bile ducts.
Etiology clues
| Gallstones | Most common cause: up to 42% in a 36-country meta-analysis (IAP 2025). An ALT above 150 U/L within 48 hours of onset has a positive predictive value above 85% for a biliary cause. |
|---|---|
| Alcohol | About 25% to 40% of cases (IAP 2025). Attribute it only after more than 5 years of moderate to heavy drinking, generally more than 50 g a day (ACG 2024). Plan for withdrawal. |
| Triglycerides | A level above 1,000 mg/dL (11.3 mmol/L) is needed to call it the cause (ACG 2024). Levels fall quickly with fasting, so use the first sample. If suspected, repeat a fasting level about 1 month after discharge. |
| Calcium | Use albumin-adjusted or ionized calcium. If high, check PTH (IAP 2025). Calcium can be normal during severe attacks: repeat it after recovery if suspicion persists. |
| Drugs | Often blamed, rarely proven. Azathioprine, 6-mercaptopurine and didanosine clearly can cause it (ACG 2024). |
| No cause found | Age over 40 (ACG) or over 50 (IAP): CT or MRI to exclude a pancreatic tumor. Idiopathic after discharge: repeat ultrasound, then EUS, then MRI with MRCP; consider genetic testing after a recurrence (IAP 2025). |
ERCP in gallstone pancreatitis
| Cholangitis | ERCP within 24 hours lowers morbidity and mortality (ACG 2024 key concept). IAP 2025: early ERCP is recommended (strong recommendation). |
|---|---|
| No cholangitis | Medical therapy over early ERCP within 72 hours, whether predicted mild or severe (ACG 2024 conditional; IAP 2025 strong). |
| Duct stone suspected | No cholangitis or jaundice: MRCP or EUS first and avoid diagnostic ERCP (ACG 2024). A stone confirmed on imaging gets elective ERCP (IAP 2025). |
| Unfit for surgery | ERCP with sphincterotomy is the alternative when cholecystectomy cannot be done in the same admission (IAP 2025). |
Acute pancreatitis · 3 of 6
Grade it by organ failure.
Revised Atlanta severity (2012)
| Mild | No organ failure and no local or systemic complications. |
|---|---|
| Moderately severe | Transient organ failure (resolves within 48 hours), or local or systemic complications, without persistent organ failure. |
| Severe | Persistent organ failure: more than 48 hours. In large cohorts mortality is 39% to 42% (IAP 2025). |
Organ failure, defined
A modified Marshall score of 2 or more in any of three systems: respiratory (PaO2/FiO2 300 or less), renal (creatinine 1.9 mg/dL or 170 µmol/L or more) or cardiovascular (systolic pressure under 90 mm Hg that does not respond to fluid). Local complications are collections and necrosis. A systemic complication is a flare of a pre-existing comorbidity such as coronary disease or chronic lung disease.
Early predictors (first 24 to 48 hours)
| SIRS | Two or more of: temperature above 38 or below 36 °C; heart rate above 90; respiratory rate above 20 or PaCO2 below 32 mm Hg; WBC above 12,000 or below 4,000/mm3 or more than 10% bands. SIRS at admission and persisting at 48 hours predicts severe disease (IAP 2025, strong). Early SIRS is 85% sensitive for organ failure but only 41% specific (ACG 2024). |
|---|---|
| BISAP | One point each in the first 24 hours: BUN above 25 mg/dL, impaired mental status, SIRS, age above 60, pleural effusion. In the derivation study, in-hospital mortality ranged from under 1% at the lowest scores to over 20% at the highest (Wu 2008). |
| Limits | No score predicts severe disease well: at best half of those predicted severe turn out severe, while a predicted-mild course is reliable (ACG 2024). Older age, comorbidity, obesity and hypertriglyceridemia add risk (IAP 2025). |
Where to admit — SIRS or any organ failure: monitored bed (ACG 2024). Modified Marshall 2 or more in any system: ICU (IAP 2025 good practice statement). Clinicians should remain vigilant for progression through the first 48 hours, even when the patient looks mild.
Acute pancreatitis · 4 of 6
Moderate fluids, then reassess.
What WATERFALL showed (NEJM 2022)
Aggressive lactated Ringer's (20 mL/kg bolus, then 3 mL/kg/h) versus moderate (10 mL/kg bolus only if hypovolemic, then 1.5 mL/kg/h). The trial stopped at the interim analysis of 249 patients. Fluid overload occurred in 20.5% versus 6.3%, and moderately severe or severe pancreatitis in 22.1% versus 17.3% (not significant). Aggressive fluids caused harm without benefit.
The moderate plan, as run in the trial
| Fluid | Lactated Ringer's over normal saline (ACG 2024 conditional; IAP 2025 strong). Exception: marked hypercalcemia, where IAP advises isotonic saline rather than lactated Ringer's. |
|---|---|
| Start | 1.5 mL/kg/h. Give a 10 mL/kg bolus over 2 hours first only if any hypovolemia criterion is present (IAP 2025: bolus for hypovolemia or hypotension). |
| Hypovolemia, any one | Creatinine above 1.1 mg/dL or BUN above 20 mg/dL; hematocrit above 44%; rising creatinine or BUN; urine output under 0.75 mL/kg/h; systolic pressure under 90 mm Hg with no other cause; clinical dehydration. |
| Check at 3 h | Look for fluid overload: dyspnea, edema, crackles, raised JVP, congestion on imaging. |
| Then at 12, 24, 48, 72 h | No hypovolemia or overload: continue 1.5 mL/kg/h. Hypovolemia: repeat 10 mL/kg over 2 hours. Further boluses before 24 hours only for urine output under 0.5 mL/kg/h or systolic pressure under 90. Overload: slow or stop. |
| Stop | After 8 hours of tolerated oral intake, as early as about 20 hours in. |
| Enough looks like | MAP 65 to 85 mm Hg, urine at least 0.5 mL/kg/h, BUN under 20 mg/dL and hematocrit under 44% (IAP 2025). ACG 2024 frames the goal as not letting BUN and hematocrit rise over the first 24 to 48 hours, with reassessment within 6 hours. |
Who the trial left out — WATERFALL excluded heart failure (NYHA II or worse, or EF under 50%), decompensated cirrhosis, eGFR under 60, signs of overload, shock or respiratory failure at entry, and arrival more than 24 hours after pain onset. For them the weight-based numbers are a starting point, not a plan. Bedside tools: fluid responsiveness and why not saline.
Acute pancreatitis · 5 of 6
Treat pain, feed early, hold antibiotics.
Supportive care
| Pain | Opioids or NSAIDs are both acceptable; opioids relieve severe pain better (IAP 2025, strong). Avoid opioids with respiratory depression, altered sensorium or ileus. Reassess pain on a numeric scale. See multimodal pain control. |
|---|---|
| Mild: eat | Oral feeding within 24 to 48 hours as tolerated, starting with a low-fat solid diet rather than clear liquids (ACG 2024). IAP 2025: start as soon as there is appetite and no vomiting. |
| Cannot eat | Enteral feeding, preferably within 72 hours (IAP 2025), by nasogastric or nasojejunal tube. Parenteral nutrition only if the gut fails or cannot meet needs (ACG 2024). See ICU nutrition. |
| No prophylaxis | Prophylactic antibiotics do not prevent infected necrosis, even in predicted severe or necrotizing disease (IAP 2025 strong, high-quality evidence; ACG 2024). |
| When to treat | Proven extrapancreatic infection (cholangitis, pneumonia, bacteremia) or strong suspicion of infected necrosis. Gas in a necrotic collection on CT suggests infection. CRP, WBC or procalcitonin alone should not trigger antibiotics (IAP 2025). |
Collections and timing
| First 4 weeks | Acute peripancreatic fluid collection (interstitial disease) or acute necrotic collection (necrotizing disease). No defined wall (Revised Atlanta). |
|---|---|
| After about 4 weeks | Pseudocyst (fluid, defined wall) or walled-off necrosis (encapsulated necrotic debris). |
| Sterile necrosis | Supportive care. Intervene only for persistent symptoms such as pain, gastric outlet or biliary obstruction, or failure to feed (IAP 2025). |
| Infected necrosis | Antibiotics first and delay intervention until the collection walls off, which takes around 3 to 4 weeks (ACG 2024: preferably 4 weeks; IAP 2025 says necrosis usually walls off after 3 to 4 weeks, and Q37 says around 4). Earlier drainage (under 4 weeks) may be appropriate when conservative care including antibiotics has failed and the collection is at least partly encapsulated; 43% show a wall within 3 weeks (IAP 2025 Q38, conditional). In POINTER (NEJM 2021), immediate drainage was no better than postponed; postponed meant fewer procedures, and 39% needed none. |
| Step-up | Antibiotics, then percutaneous or endoscopic transluminal drainage, then minimally invasive necrosectomy if needed (IAP 2025, strong). In PANTER (NEJM 2010), death or major complications fell from 69% with open necrosectomy to 40%; 35% needed drainage only. |
Gallbladder out on the index admission — mild gallstone pancreatitis: cholecystectomy before discharge (ACG 2024; IAP 2025, strong). In PONCHO (Lancet 2015), readmission for gallstone complications or death was 17% after interval surgery versus 5% after same-admission surgery. Necrotizing or moderately severe to severe disease: delay until collections resolve or are drained (IAP 2025).
Acute pancreatitis · 6 of 6
Hypertriglyceridemia: confirm, lower, prevent.
Confirm and support
| Threshold | Hypertriglyceridemia causes about 5% of all cases (ACG 2024); IAP 2025 puts it at up to 10%, and it can run a more severe course. To call it the cause, triglycerides must be above 1,000 mg/dL (11.3 mmol/L) with no other cause (ACG 2024). Trials of TG lowering enrolled at this level (Bi-TPAI protocol; Le 2025). |
|---|---|
| Standard care | Everything above applies: the same diagnosis, fluids, analgesia and severity grading. |
| Diet | IAP 2025 departs from early feeding here: fast for the first 48 hours, then a low-fat soft diet, or tube feeding if oral intake fails. If parenteral nutrition is needed, no IV fat emulsion while TG is above 400 mg/dL. |
| Look for DKA | If glucose is high, check ketones and the anion gap before choosing an insulin plan: DKA has its own protocol. See the DKA and HHS tool. |
IV insulin: guideline stance and one published protocol
| Stance | IAP 2025: insulin is recommended in diabetics and may be considered in non-diabetics as first-line TG lowering (strong recommendation, moderate evidence). Short-term LMWH (under 3 days) may also be considered (conditional). There is no consensus dose. |
|---|---|
| Protocol | Regular insulin at 0.1 units/kg/h, titrated up to 0.3 units/kg/h (Bi-TPAI protocol, Trials 2019; used in Le 2025). Continue until TG is under 500 mg/dL (5.6 mmol/L). |
| Dextrose | Bi-TPAI: run 5% or stronger dextrose to keep glucose 120 to 200 mg/dL (6.7 to 11.1 mmol/L). Le 2025: start 5% dextrose once glucose reaches 150 to 200 mg/dL. |
| Monitor | Glucose closely. Potassium: Le 2025 added it to fluids and adjusted it every 4 hours. Delaying insulin until K is above 3.5 mmol/L is borrowed from the 2024 DKA consensus, since no HTG-specific threshold exists. TG at 12, 24, 48 and 72 hours (Le 2025). |
| Harms | In Le 2025 (54 patients), hypoglycemia occurred in 16.7% and hypokalemia in 18.5%. |
Faster TG lowering is not proven to help — in a 106-patient cohort, IV insulin did not lower TG faster than fasting and fluids alone; both groups fell below 1,000 mg/dL by day 3 and below 500 by day 4 (Dhindsa 2019). A 2026 network meta-analysis found no consistent gain in mortality, organ failure or length of stay from faster lowering by any method (Liang 2026). Treat insulin as a reasonable option, not an emergency.
Apheresis: a selective option
| IAP 2025 | May be considered for persistent organ failure with high TG, particularly with acute kidney failure (conditional, low-quality evidence). A systematic review found no clear outcome benefit, and a multicenter cohort found no reduction in organ failure, with longer ICU stays. |
|---|---|
| ASFA | The 2023 ninth edition lists hypertriglyceridemic pancreatitis as category III: the role of apheresis is not established, so decide case by case. A tenth edition was published in September 2026; confirm the current fact sheet. |
After discharge: keep TG under 500 mg/dL
| Target | TG consistently under 500 mg/dL to prevent relapse (IAP 2025, conditional). Recheck a fasting level about 1 month out (ACG 2024). |
|---|---|
| Fibrate | Fenofibrate is the usual first drug, but no trial shows it prevents recurrent pancreatitis (IAP 2025). Its label says the effect on pancreatitis risk has not been adequately studied. |
| Omega-3 | Icosapent ethyl is FDA-labeled as an adjunct to diet for TG of 500 mg/dL or more, but the label states its effect on pancreatitis risk has not been determined. An HCPLive commentary on the 2026 ACC/AHA dyslipidemia guideline reports that it treats fibrates and high-dose prescription omega-3 as appropriate adjuncts above 500 to 1,000 mg/dL, with dietitian referral for patients at risk of pancreatitis; confirm the recommendation classes in the guideline itself. |
| Olezarsen | APOC3 antisense (Tryngolza). FDA-approved December 19, 2024 for familial chylomicronemia syndrome (80 mg monthly). On June 24, 2026 the FDA added severe hypertriglyceridemia (TG 500 mg/dL or more) to reduce TG and the risk of acute pancreatitis: 50 mg monthly, increased to 80 mg if needed. In CORE and CORE2 (NEJM 2026), placebo-adjusted TG fell 49% to 72% at 6 months, with an acute pancreatitis rate ratio of 0.15. |
| Plozasiran | APOC3 siRNA (Redemplo). FDA-approved November 18, 2025 for familial chylomicronemia syndrome only, 25 mg every 3 months. Not approved for severe hypertriglyceridemia: phase 3 SHASTA-3 and SHASTA-4 topline results came in July 2026, and the company planned to file before the end of 2026. |
ACG American College of GastroenterologyIAP International Association of PancreatologyAPA / EPC American Pancreatic Association / European Pancreatic ClubACC / AHA American College of Cardiology / American Heart AssociationFDA US Food and Drug AdministrationCT / MRI computed tomography / magnetic resonance imagingMRCP magnetic resonance cholangiopancreatographyEUS endoscopic ultrasoundERCP endoscopic retrograde cholangiopancreatographySIRS systemic inflammatory response syndromeBISAP Bedside Index of Severity in Acute PancreatitisTG triglyceridesLMWH low-molecular-weight heparinASFA American Society for ApheresisAPOC3 apolipoprotein C-IIIPTH parathyroid hormoneALT alanine aminotransferaseBUN blood urea nitrogenWBC white blood cell countCRP C-reactive proteinPaO2 / FiO2 / PaCO2 arterial oxygen tension / inspired oxygen fraction / arterial carbon dioxide tensionMAP mean arterial pressureJVP jugular venous pressureEF ejection fractionNYHA New York Heart AssociationICU intensive care uniteGFR estimated glomerular filtration ratesiRNA small interfering RNANSAIDs nonsteroidal anti-inflammatory drugsIV intravenousDKA / HHS diabetic ketoacidosis / hyperglycemic hyperosmolar stateHTG hypertriglyceridemiaNEJM New England Journal of MedicineBi-TPAI intensive insulin vs plasmapheresis trial protocol (Song 2019)
Educational reference only — not medical advice. Verify against local protocol.
Sources
Verify against current guidelines and local protocol before acting.
- Tenner S, Vege SS, Sheth SG, et al. American College of Gastroenterology Guidelines: Management of Acute Pancreatitis. Am J Gastroenterol 2024;119(3):419-437. doi:10.14309/ajg.0000000000002645
- 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;25(6):770-814. doi:10.1016/j.pan.2025.04.020
- Banks PA, Bollen TL, Dervenis C, et al. Classification of acute pancreatitis 2012: revision of the Atlanta classification and definitions by international consensus. Gut 2013;62:102-111. doi:10.1136/gutjnl-2012-302779
- de-Madaria E, Buxbaum JL, Maisonneuve P, et al. Aggressive or moderate fluid resuscitation in acute pancreatitis (WATERFALL). N Engl J Med 2022;387:989-1000. doi:10.1056/NEJMoa2202884. Trial protocol: Front Med (Lausanne) 2020;7:440. doi:10.3389/fmed.2020.00440
- Wu BU, Johannes RS, Sun X, et al. The early prediction of mortality in acute pancreatitis: a large population-based study (BISAP). Gut 2008;57:1698-1703. doi:10.1136/gut.2008.152702
- Bone RC, Balk RA, Cerra FB, et al. Definitions for sepsis and organ failure (ACCP/SCCM consensus). Chest 1992;101:1644-1655. doi:10.1378/chest.101.6.1644
- van Santvoort HC, Besselink MG, Bakker OJ, et al. A step-up approach or open necrosectomy for necrotizing pancreatitis (PANTER). N Engl J Med 2010;362:1491-1502. doi:10.1056/NEJMoa0908821
- Boxhoorn L, van Dijk SM, van Grinsven J, et al. Immediate versus postponed intervention for infected necrotizing pancreatitis (POINTER). N Engl J Med 2021;385:1372-1381. doi:10.1056/NEJMoa2100826
- da Costa DW, Bouwense SA, Schepers NJ, et al. Same-admission versus interval cholecystectomy for mild gallstone pancreatitis (PONCHO). Lancet 2015;386:1261-1268. doi:10.1016/S0140-6736(15)00274-3
- Song X, Shi D, Cui Q, et al. Intensive insulin therapy versus plasmapheresis in hypertriglyceridemia-induced acute pancreatitis (Bi-TPAI trial): study protocol. Trials 2019;20:365. doi:10.1186/s13063-019-3498-x
- Le TQ, Le HTT, Tran NTT, et al. Effectiveness of continuous intravenous insulin infusion in hypertriglyceridemia-induced acute pancreatitis of varying severity. Medicine (Baltimore) 2025;104(22):e42674. doi:10.1097/MD.0000000000042674
- Dhindsa S, Sharma A, Al-Khazaali A, et al. Intravenous insulin versus conservative management in hypertriglyceridemia-associated acute pancreatitis. J Endocr Soc 2019;4(1):bvz019. doi:10.1210/jendso/bvz019
- Liang AC, Castillo YC, et al. Comparative efficacy of insulin and alternative therapies for hypertriglyceridemia-associated acute pancreatitis: systematic review and network meta-analysis. Dig Dis Sci 2026;71(10):4932-4957. doi:10.1007/s10620-026-10052-2
- Umpierrez GE, Davis GM, ElSayed NA, et al. Hyperglycaemic crises in adults with diabetes: a consensus report. Diabetologia 2024;67:1455-1479 (also Diabetes Care 2024;47:1257-1275). doi:10.1007/s00125-024-06183-8. Potassium threshold applied here by analogy only.
- Connelly-Smith L, Alquist CR, Aqui NA, et al. Guidelines on the Use of Therapeutic Apheresis in Clinical Practice: The Ninth Special Issue (ASFA). J Clin Apher 2023;38(2):77-278. doi:10.1002/jca.22043. Category as reported in Gubensek J. BMC Gastroenterol 2023;23:341. doi:10.1186/s12876-023-02957-3. Tenth Special Issue: Zantek ND, et al. J Clin Apher 2026;41(Suppl 2):e70141. doi:10.1002/jca.70141 (PMID 42747330); confirm the current fact sheet
- Marston NA, Bergmark BA, Alexander VJ, et al. Olezarsen for managing severe hypertriglyceridemia and pancreatitis risk (CORE-TIMI 72a and CORE2-TIMI 72b). N Engl J Med 2026;394(5):429-441. doi:10.1056/NEJMoa2512761
- TRYNGOLZA (olezarsen) prescribing information, Ionis Pharmaceuticals, revised 06/2026 (DailyMed setid 0f51aa8e-8475-8cf9-e063-6394a90a6848). Ionis press releases December 19, 2024 (FCS approval) and June 24, 2026 (sHTG approval).
- REDEMPLO (plozasiran) prescribing information, Arrowhead Pharmaceuticals (DailyMed setid 7fd37993-f85a-4af1-8bbe-133299f226ed); FDA approval November 18, 2025. Arrowhead topline SHASTA-3/SHASTA-4 release, July 22, 2026.
- VASCEPA (icosapent ethyl) prescribing information, Amarin (DailyMed, March 2026). TRICOR (fenofibrate) prescribing information (DailyMed).
- Blumenthal RS, Morris PB, Gaudino M, et al. 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia. Circulation 2026;153(17):e1154-e1276. doi:10.1161/CIR.0000000000001423. Triglyceride points as reported in an HCPLive commentary (2026); the guideline full text was not accessible, so recommendation classes are not restated.
- Tables and wording are our own; no society figure or table is reproduced.