Acute Pancreatitis

Gastroenterology

OverviewWhoPresentationMechanismWorkupManagementPivots

Illness script · Gastroenterology

Acute Pancreatitis

Acute inflammation of the pancreas due to premature activation of digestive enzymes, causing autodigestion and systemic inflammation.

This illness script for Acute Pancreatitis covers predisposing factors, classic presentation, mechanism, workup, management, and the clinical pivots that separate it from look-alikes—written for USMLE Step 1 and clerkship reasoning.

Updated Jul 19, 2026All scripts

01

Predisposing factors

  • Gallstones (#1 cause, ~40%) and alcohol (#2 cause, ~30%)
  • 'GET SMASHED' mnemonic covers all major etiologies
  • Hypertriglyceridemia (>1000 mg/dL triggers pancreatitis)
  • Medications: azathioprine, valproate, furosemide, thiazides, sulfonamides
  • ERCP is most common iatrogenic cause
  • Younger patients: consider CF, autoimmune, hereditary pancreatitis

02

Presentation

  • Epigastric pain radiating to the back, onset after fatty meal or alcohol binge
  • Nausea and vomiting that does NOT relieve the pain (key feature)
  • Low-grade fever, tachycardia; periumbilical or flank ecchymosis in severe hemorrhagic disease (Cullen/Grey Turner signs)
  • Abdominal tenderness with guarding; decreased bowel sounds (ileus)
  • Ranson/BISAP criteria assess severity at admission and 48 hours
  • Severe disease: hypotension, respiratory distress (ARDS), hypocalcemia (saponification)

03

Pathophysiology

  • Premature intracellular trypsinogen activation → autodigestion of pancreatic parenchyma
  • Local inflammation → cytokine release → SIRS, ARDS, multi-organ failure
  • Gallstone pancreatitis: transient ampullary obstruction → ductal hypertension
  • Alcoholic: direct toxic effect on acinar cells + protein plug obstruction

04

Diagnostics

  • Serum lipase >3× ULN is first-line and most specific (preferred over amylase)
  • Amylase rises faster but normalizes sooner and is less specific
  • CT abdomen with IV contrast is gold standard for complications (necrosis, abscess) — not needed for diagnosis alone
  • Obtain at 48–72 hours if no clinical improvement to evaluate necrotizing pancreatitis
  • RUQ ultrasound first-line imaging to identify gallstones as etiology
  • Lipase can be normal in hypertriglyceridemia-induced pancreatitis (pearl)

05

Management

  • Aggressive IV fluid resuscitation (Lactated Ringer's preferred over NS) is cornerstone
  • NPO initially; early enteral feeding (nasojejunal) preferred over TPN in severe disease
  • Pain control: IV opioids (morphine/hydromorphone); no contraindication to morphine
  • Gallstone pancreatitis: ERCP if concurrent cholangitis; cholecystectomy before discharge
  • Infected pancreatic necrosis: IV antibiotics (imipenem/meropenem) ± CT-guided drainage or necrosectomy
  • Alcohol-induced: no role for prophylactic antibiotics; address underlying use disorder

06

Clinical pivots

How to separate this script from the look-alikes that show up on exams and on the wards.

  • Peptic Ulcer Disease / Perforated Ulcer

    Perforated ulcer causes sudden rigid 'board-like' abdomen; free air on upright CXR; lipase not markedly elevated

  • Acute Cholecystitis

    Pain localizes to RUQ with Murphy's sign; lipase normal unless concurrent pancreatitis; fever more prominent early

  • Mesenteric Ischemia

    'Pain out of proportion to exam'; older patient with afib or atherosclerosis; lactate elevated; CT shows bowel wall changes

  • Aortic Dissection / AAA

    Tearing pain radiates to back/flank; pulsatile mass or BP differential between arms; CT angio confirms; lipase normal

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Educational use only. This illness script is a study framework, not medical advice. Confirm decisions with current guidelines and your clinical supervisors.