Acute Pancreatitis
Sudden inflammation of the pancreas, most often from gallstones or alcohol; severity-driven management.
Also known as: acute pancreatitis, gallstone pancreatitis, alcoholic pancreatitis
Overview
Acute inflammatory process of the pancreas with potential involvement of peripancreatic tissues or remote organ systems. Diagnosed by ≥2 of: characteristic abdominal pain, lipase or amylase ≥3× upper limit of normal, or characteristic imaging findings.
Epidemiology
Incidence 30-50 per 100,000/yr in the US; rising. Mortality 1-3% overall; up to 20% in severe necrotizing disease. Most common GI cause of hospital admission.
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Risk factors
- Gallstones (most common, ~40%)
- Alcohol (~30%)
- Hypertriglyceridemia (>1000 mg/dL; ~5%)
- Hypercalcemia
- Post-ERCP (~5% of ERCPs)
- Medications: azathioprine/6-MP, GLP-1 agonists (debated), DPP-4 inhibitors, valproate, didanosine, pentamidine, estrogens, thiazides, furosemide, sulfa drugs, statins, mesalamine, asparaginase
- Trauma (especially blunt — pediatric handlebar injury)
- Autoimmune (IgG4-related — type 1; idiopathic duct-centric — type 2)
- Hereditary (PRSS1, SPINK1, CFTR mutations)
- Pancreas divisum, sphincter of Oddi dysfunction
- Infections: mumps, coxsackievirus, CMV, mycoplasma
- Smoking
- Idiopathic (~10-20%)
Pathophysiology
Premature intra-acinar activation of trypsinogen to trypsin initiates auto-digestion of pancreatic tissue. Local inflammatory cascade and release of cytokines drive edema, hemorrhage, fat necrosis, and pancreatic/peripancreatic necrosis. Systemic inflammatory response (SIRS) and multiorgan dysfunction occur in severe disease.
Clinical presentation
Symptoms
- Sudden, severe epigastric pain radiating to the back, often constant
- Pain relieved by leaning forward, worse supine
- Nausea and vomiting (often persistent)
- Anorexia
- Fever (mild; high fever suggests cholangitis or necrosis with infection)
- Symptoms of SIRS/sepsis in severe disease
Signs / physical exam
- Epigastric tenderness, guarding
- Diminished bowel sounds (ileus)
- Tachycardia, hypotension if severe
- Jaundice if gallstone etiology
- Cullen sign (periumbilical ecchymosis) — hemorrhagic pancreatitis (rare, late)
- Grey-Turner sign (flank ecchymosis) — hemorrhagic pancreatitis (rare, late)
- Fox sign (inguinal ecchymosis)
- Tetany or trousseau sign if severe hypocalcemia
Classic findings
Sudden epigastric pain radiating to back with markedly elevated lipase (>3× ULN) in a patient with gallstones or alcohol use.
Differential diagnosis
- Peptic ulcer (perforated) — Sudden severe epigastric pain, peritonitis, free air on imaging
- Acute cholecystitis / cholangitis — RUQ pain, fever, jaundice; lipase may be mildly elevated
- Mesenteric ischemia — Pain out of proportion, lactic acidosis, atrial fibrillation; CT angio
- Ruptured AAA — Hypotension, pulsatile abdominal mass, severe back pain; emergent CT
- Inferior MI — Atypical epigastric pain; ECG and troponin in older patients
- Diabetic ketoacidosis — Hyperglycemia, anion gap acidosis, ketones; lipase mildly elevated (false positive)
- Bowel obstruction — Distension, constipation/obstipation, vomiting; imaging
- Renal colic — Flank pain, hematuria; CT
Diagnostic workup
Diagnostic criteria
Revised Atlanta Classification (2012): diagnosis requires 2 of 3: (1) typical abdominal pain; (2) lipase/amylase ≥3× ULN; (3) characteristic imaging. Severity: Mild (no organ failure, no local/systemic complications), Moderate (transient organ failure <48 h or local/systemic complications), Severe (persistent organ failure ≥48 h).
Labs
- LIPASE (preferred) or amylase — elevation ≥3× ULN supports diagnosis; lipase more specific and remains elevated longer
- CBC — hematocrit (hemoconcentration from third-spacing); WBC
- BMP — BUN/creatinine (volume status, prognostic); glucose; calcium
- LFTs — ALT >150 strongly suggests gallstone etiology (NPV high if normal)
- Triglycerides — exclude hypertriglyceridemic pancreatitis (>500-1000)
- Calcium — hyper- (cause) or hypocalcemia (complication)
- Lactate if severe
- ABG, lactate dehydrogenase for severity scoring (Ranson, APACHE)
- CRP at 48 h — >150 predicts severe disease
Imaging
- Abdominal ultrasound — FIRST imaging in all patients to exclude gallstones (etiology), not for severity
- CT abdomen with IV contrast — NOT required at presentation if diagnosis is clinical; obtain at 72 h or later to stratify severity and identify necrosis, peripancreatic collections; earlier CT if diagnosis unclear or rapid deterioration
- MRI/MRCP — if CT contraindicated or CBD stone suspected
- EUS — recurrent idiopathic pancreatitis evaluation
Diagnostic algorithm
| BISAP Criterion (0-5) | Threshold |
|---|---|
| B — BUN | >25 mg/dL |
| I — Impaired mental status | GCS <15 |
| S — SIRS | ≥2 criteria |
| A — Age | >60 yr |
| P — Pleural effusion | Present on imaging |
| Score interpretation | ≥3 = high risk for severe pancreatitis and mortality |
Treatment
First-line
- Aggressive IV fluid resuscitation — lactated Ringer's at 5-10 mL/kg/h titrated to urine output >0.5 mL/kg/h and clinical response; avoid over-resuscitation (worsens outcomes)
- Pain control — IV opioids (hydromorphone, fentanyl)
- Antiemetics, NPO initially but early oral feeding (low-fat soft diet) within 24-48 h as tolerated improves outcomes
- Identify and treat etiology
- Monitor in step-down or ICU based on severity
Gallstone pancreatitis
- Same-admission cholecystectomy for mild disease (PONCHO trial) to prevent recurrence
- Delay cholecystectomy 4-6 weeks for severe disease until inflammation resolves
- ERCP only if concurrent cholangitis or persistent obstruction
Alcohol-induced pancreatitis
- Alcohol cessation counseling; treat withdrawal
- Nutritional support (thiamine, folate, multivitamin)
- Smoking cessation (synergistic risk for chronic pancreatitis)
Hypertriglyceridemic pancreatitis
- IV insulin infusion (lowers TG) ± plasmapheresis if TG >1000 with end-organ damage
- Long-term fibrate ± omega-3 fatty acids; dietary fat restriction
- Control underlying diabetes, alcohol, OCP, estrogens, beta-blockers
Second-line / adjunct
- Enteral nutrition (nasogastric or nasojejunal) preferred over TPN in severe disease unable to eat by day 5-7
- Antibiotics — NOT routine; reserve for confirmed infected necrosis (positive FNA culture or gas in necrosis) or concurrent extra-pancreatic infection (cholangitis, pneumonia, line sepsis); carbapenem or piperacillin-tazobactam
- ERCP within 24-48 h ONLY if concurrent ascending cholangitis or persistent CBD obstruction; not for uncomplicated gallstone pancreatitis
- Plasmapheresis or insulin/heparin infusion for hypertriglyceridemic pancreatitis (TG >1000)
- Step-up approach for necrotizing pancreatitis: percutaneous drainage → minimally invasive necrosectomy (video-assisted retroperitoneal debridement or endoscopic transluminal) → open necrosectomy as last resort (PANTER trial)
Complications
- Acute peripancreatic fluid collection (early; resolves spontaneously)
- Pancreatic pseudocyst (after 4 weeks; intervene only if symptomatic or infected)
- Acute necrotic collection (early necrosis)
- Walled-off pancreatic necrosis (after 4 weeks)
- Infected pancreatic necrosis — high mortality; FNA + culture; step-up drainage
- ARDS, AKI, DIC, shock (severe disease)
- Hypocalcemia (saponification), hypomagnesemia, hyperglycemia
- Pancreatic abscess
- Splenic vein thrombosis with isolated gastric varices
- Pseudoaneurysm (especially splenic artery)
- Progression to chronic pancreatitis (especially alcohol etiology)
- Diabetes mellitus, exocrine insufficiency
PANCE pearls
- Lipase >3× ULN is more specific than amylase and remains elevated longer.
- Magnitude of lipase does NOT correlate with severity.
- ALT >150 strongly suggests gallstone etiology — pursue RUQ ultrasound.
- DO NOT routinely give prophylactic antibiotics for sterile necrosis — only for infected necrosis or extra-pancreatic infection.
- Aggressive IV fluids in the first 24 h reduce mortality; lactated Ringer's reduces SIRS compared with normal saline (Wu, Clin Gastroenterol Hepatol 2011).
- AVOID over-resuscitation — increases mortality, ARDS, abdominal compartment syndrome.
- Same-admission cholecystectomy for mild gallstone pancreatitis (PONCHO trial).
- Early enteral feeding within 24-48 h improves outcomes vs prolonged NPO.
- Step-up approach (drainage first, surgery last) reduces morbidity in necrotizing pancreatitis (PANTER trial).
- Revised Atlanta Classification: mild, moderate, severe — severity determined by organ failure (Marshall score) and complications.
- BISAP score (BUN >25, impaired mental status, SIRS ≥2, age >60, pleural effusion) — practical early severity score.
- ERCP urgent only for concurrent cholangitis or persistent obstruction — not for uncomplicated gallstone pancreatitis.
References
- ACG 2013 — Tenner S et al. American College of Gastroenterology Guideline: Management of Acute Pancreatitis. Am J Gastroenterol 2013;108:1400-1415
- Revised Atlanta — Banks PA et al. Classification of acute pancreatitis—2012: revision of the Atlanta classification and definitions. Gut 2013;62:102-111
- PANTER Trial — van Santvoort HC et al. A Step-up Approach or Open Necrosectomy for Necrotizing Pancreatitis. NEJM 2010;362:1491-1502
- PONCHO Trial — da Costa DW et al. Same-admission versus interval cholecystectomy for mild gallstone pancreatitis. Lancet 2015;386:1261-1268
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