Acute Pancreatitis

Background

Most common etiologies: Gallstones (40%), EtOH (30%).
Other causes include: post-ERCP, obstruction (malignancy), blunt abdominal trauma, hypertriglyceridemia, hypercalcemia, drugs (thiazides, protease inhibitors, azathioprine, 6MP), mumps, Coxsackie, vasculitis, pregnancy, genetic (PRSS1, SPINK1, CFTR), autoimmune (IgG4), scorpions.

2 of 3 criteria: (1) epigastric pain radiating to back; (2) lipase >3× ULN; (3) imaging consistent with pancreatitis.
Initial workup:
- Labs: lipase, CBC, CMP, lipid panel, lactate, direct bilirubin.
- Imaging:
  - RUQ ultrasound (evaluates for gallstones).
  - CT A/P with IV contrast: reserve if no improvement at 48–72h (early CT underestimates necrosis).
Severity (Revised Atlanta): Mild = no organ failure, no complications. Moderately severe = transient organ failure (<48 hrs) OR local complications. Severe = persistent organ failure (>48 hrs). Severity declares within 48 hours of admission.

Fluids (WATERFALL Trial, NEJM 2022): Avoid aggressive resuscitation (↑ overload, no benefit).
- Normovolemia: start at 1.5 mL/kg/hr (no bolus)
- Hypovolemia: bolus 10 mL/kg over 2 hours then 1.5 mL/kg/hr
- Lactated Ringer's preferred over NS
- Monitor HCT and BUN q6-8h; persistent hemoconcentration at 24 hours is associated with necrotizing pancreatitis.
Pain: Oxycodone 5-10 mg PO q6h PRN + hydromorphone 0.5 mg IV q4h for breakthrough.
Nutrition: Start oral low-fat diet within 24-48 hours if tolerated. If NPO >72h, initiate enteral nutrition. Enteral >> TPN (↓ mortality, infection, organ failure).
Antibiotics: No role for prophylactic abx. Suspect infected necrosis if no improvement ≥7d or gas on CT (at that point, empiric coverage with good pancreatic penetration: cefepime + metronidazole OR meropenem).
ERCP: NOT routine in gallstone pancreatitis. Urgent (< 24h) only for cholangitis or persistent cholestasis (bilirubin >3-5 mg/dL). If CBD stone suspected without cholangitis: MRCP or EUS first.
Cholecystectomy: Same-admission for mild gallstone pancreatitis. Delay ≥6 weeks for moderate/severe or if peripancreatic collections.

Early (<4 weeks): peripancreatic fluid collection, necrotic collection.
Late (>4 weeks): pseudocyst, walled-off necrosis (WON).
Infected necrosis: step-up approach (percutaneous/endoscopic drainage → necrosectomy); delay ≥4 weeks for WON maturation; EUS-guided cystogastrostomy first-line for symptomatic WON.
Systemic: ARDS, AKI, DIC, abdominal compartment syndrome.

TG >1000 mg/dL.
Nearly all patients have genetic predisposition + secondary factor (DM, alcohol, estrogen, hypothyroidism, propofol, ART).
Note: HTG can cause falsely low amylase and affect Na, glucose, LDL measurements.
Acute management: NPO initially (stops chylomicron production, TG falls rapidly) + standard pain management + severe fat restriction (<5–10%) until TG <1000 mg/dL.
Insulin infusion: in hyperglycemic patients (activates lipoprotein lipase → accelerates TG clearance); if euglycemic, low-dose insulin (1-2 units/hr) + dextrose (however, Endocrine Society 2020 against routine insulin in euglycemic patients). Monitor TG q12h; goal <500 mg/dL.
Plasmapheresis: not first-line (no RCT mortality benefit). Consider only for TG >10,000 mg/dL, refractory cases, multi-organ dysfunction, or pregnancy.
Long-term (when TG <1000 mg/dL): Fibrates (fenofibrate first-line), omega-3, statins, niacin. Lifestyle: eliminate alcohol, low-fat diet, weight loss, treat secondary causes. Goal TG <500 mg/dL to prevent recurrence.