Management of Acute Pancreatitis

1. Classification of Severity

• BISAP score (≥3 = high risk): BUN >25 mg/dL, Impaired mental status (GCS <15), SIRS, Age >60, Pleural effusion
• APACHE II score ≥8 at 24h
• Modified Marshall score for organ failure (CV: SBP <90 or HR >130; Pulmonary: PaO2 <60 mmHg; Renal: creatinine >2.0 mg/dL)
• Hematocrit >44% and admission BUN >20 mg/dL predict severity
• CRP >100 mg/L (typically peaks at 48-72h) is a useful hospitalization marker

2. Initial Assessment and Resuscitation

Fluid Resuscitation

• Use balanced crystalloid (lactated Ringer's solution preferred over normal saline - shown to reduce the systemic inflammatory response)
• Rate: aim to restore normal BP, blood volume, and urine output; some centers use 5-10 mL/kg/hr in the first 24h, but tailor to the patient
• Monitor: BUN and hematocrit should fall in the first 12-24h as confirmation of adequate resuscitation; a rising BUN is associated with higher in-hospital mortality
• Caution with aggressive resuscitation in cardiac, renal, or elderly patients (risk of over-resuscitation and abdominal compartment syndrome)

Analgesia

• Adequate analgesia is a core requirement; IV opioids (morphine, hydromorphone, fentanyl) are standard for moderate-severe pain
• Epidural analgesia may be used in severe cases
• NSAIDs and acetaminophen can supplement

Monitoring (in severe AP)

• Invasive vital signs monitoring
• Central venous pressure
• Hourly urine output
• Serial ABGs
• Frequent labs: FBC, LFTs, renal function, clotting, serum calcium, blood glucose - Bailey & Love's, p. 1294

3. Determining Etiology

• Gallstones: USS abdomen (gallstones are the cause in ~40% of cases); elevated ALP >300 IU/L, ALT >100 IU/L, amylase >4000 IU/L suggest biliary etiology
• Alcohol: confirm with blood ethanol levels
• Other: serum triglycerides, calcium (hyperparathyroidism, malignancy), full drug history, ERCP history, trauma, infection
• For idiopathic AP: consider EUS, MRCP, genetic testing (CFTR, SPINK1, PRSS1 mutations)

4. Nutritional Support

• Mild AP: Oral low-fat solid diet once able to eat; resuming intake ad libitum (patient-controlled) is safe and preferred - no need to wait for pain resolution or amylase normalization
• Moderate-severe AP: Start enteral nutrition (EN) within 24-72h of admission
  • Gastric feeding (nasogastric tube) is safe; nasojejunal feeding if intolerant
  • Advance in stepwise fashion over 2-3 days
  • Aggressive early enteral feeding before adequate resuscitation risks non-occlusive mesenteric ischemia
• Parenteral nutrition (TPN): Use only if enteral route is not achievable; TPN is more expensive, riskier, and not more effective than EN
• No evidence for elemental or immune-enhancing formulas over standard polymeric formulas - Schwartz's Surgery, p. 1471

5. Antibiotics

"Prophylactic antibiotics are no longer recommended for severe acute pancreatitis... Prophylactic antibiotics do not lead to improved survival and may promote the development of opportunistic fungal infections." - Harrison's, p. 2791

• Antibiotics indicated when:
  • Confirmed or strongly suspected infected necrosis (fever, rising WBC, gas in necrotic collection on CT)
  • Cholangitis (see ERCP below)
  • Concomitant respiratory or urinary tract infection
• Regimens used: IV cefuroxime, imipenem, or ciprofloxacin + metronidazole
• Duration should not exceed 14 days; guide further use with microbiology cultures

6. Imaging

• Ultrasound: First-line for etiology (gallstones); not reliable for grading pancreatitis severity
• Contrast-enhanced CT (CECT): Gold standard for local complications
  • Best performed 3-5 days after onset if patient is not responding to supportive care
  • Avoid routine CT within 72h (overutilized in mild disease)
  • Defines interstitial vs. necrotizing pancreatitis; guides drainage procedures
  • Perform urgently if: organ failure, clinical deterioration, or signs of sepsis develop
• MRI/MRCP: Superior to CT for detecting solid content within collections and pancreatic duct disruption; preferred if bleeding is suspected alongside a collection
• CT Severity Index (Balthazar scoring) correlates with morbidity and mortality

CT Morphology of Local Collections (Revised Atlanta)

7. ERCP in Acute Pancreatitis

• Indicated within 72 hours for:
  • Predicted or proven severe gallstone pancreatitis
  • Signs of jaundice, cholangitis, or dilated common bile duct
  • Sphincterotomy + bile duct clearance reduces infective complications
  • In cholangitis, sphincterotomy or biliary stenting is mandatory
• ERCP is not indicated for mild gallstone pancreatitis without cholangitis or ductal obstruction
• Note: ERCP carries a small risk of worsening pancreatitis

8. Management of Local Complications

Sterile Necrosis

• Managed conservatively in the majority of cases unless complications arise (hemorrhage, abdominal compartment syndrome, fistula)
• Multidisciplinary team (gastroenterology, surgery, interventional radiology, ICU) essential
• Consider transfer to a tertiary pancreas center

Infected Necrosis (Definitive Management)

• Endoscopic transmural drainage (EUS-guided) preferred - introduced transgastrically or transduodenally
• Percutaneous drainage if collection not amenable to endoscopic approach

• Endoscopic necrosectomy (direct endoscopic necrosectomy - DEN) via transgastric approach
• Video-assisted retroperitoneal debridement (VARD) or minimally invasive retroperitoneal necrosectomy
• Open necrosectomy: reserved as last resort - historically associated with 34-95% morbidity and 11-39% mortality

"The TENSION trial (2018) compared the endoscopic step-up approach (EUS-guided transluminal drainage followed by endoscopic necrosectomy if necessary) with the surgical step-up approach and found equivalent outcomes with a lower rate of complications with the endoscopic approach." - Current Surgical Therapy 14e

"A step-up approach (percutaneous or endoscopic transgastric/transduodenal drainage followed, if necessary, by endoscopic or, rarely, surgical necrosectomy) is the current treatment paradigm. Randomized trials have reported advantages..." - Harrison's, p. 2792

Pseudocysts

• Most resolve spontaneously; intervention only for symptomatic/enlarging/infected pseudocysts
• Endoscopic transmural drainage (EUS-guided cystogastrostomy) is first-line for suitable anatomy

9. Systemic Complications Management

10. Definitive Treatment - Prevention of Recurrence

Summary Algorithm

Acute Pancreatitis Suspected
         ↓
Confirm diagnosis (lipase/amylase >3x ULN ± imaging)
         ↓
Risk stratify: BISAP, SIRS, BUN, Hematocrit, Organ failure
         ↓
┌────────────────┬────────────────────────────┐
│   MILD AP      │   MODERATE-SEVERE/CRITICAL │
│  (no OF, no    │   (persistent OF >48h or   │
│  local comps)  │    necrosis/collections)   │
│                │                            │
│ IV fluids (LR) │  ICU/HDU admission         │
│ Analgesia      │  Aggressive fluid resus.   │
│ Oral diet when │  Enteral nutrition (24-72h) │
│  tolerating    │  NO prophylactic ABx       │
│ USS for etiol. │  CECT at 3-5d              │
│ Cholecystectomy│  Step-up approach for      │
│  before d/c    │   infected necrosis        │
│                │  ERCP if cholangitis       │
└────────────────┴────────────────────────────┘