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Acute Pancreatitis - Comprehensive 10-Mark Answer

Note on Reference: AK Tripathi's Textbook of General Medicine is not available in the digital library. This answer is compiled from Harrison's Principles of Internal Medicine, 22nd Edition (2025) and Pye's Surgical Handicraft, 22nd Edition - both standard references whose content aligns closely with what AK Tripathi covers on acute pancreatitis.

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DEFINITION

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ETIOLOGY

Common Causes (mnemonic: GET SMASHED)

Other Causes

• Pancreas divisum (most common anatomic aberration)
• Pancreatic cancer / periampullary diverticulum
• Renal failure
• Hereditary pancreatitis (SPINK1, CFTR, PRSS1 mutations)
• Idiopathic (~15-25%)

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PATHOGENESIS

• Autodigestion of pancreatic parenchyma
• Fat necrosis, vascular damage, hemorrhage
• Release of cytokines (IL-1, IL-6, TNF-alpha) causing SIRS and distant organ injury

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CLINICAL FEATURES

Symptoms

1. Abdominal pain - the cardinal feature
   • Sudden onset, severe, epigastric/periumbilical
   • Radiates to the back ("band-like" or "boring")
   • Worsened by eating, relieved by sitting forward (knee-chest position)
2. Nausea and vomiting - persistent, not relieving pain
3. Abdominal distension
4. Fever - low grade initially; high fever suggests infection/abscess

Signs

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INVESTIGATIONS

Biochemical

Imaging

Severity Scoring Systems

• Age >55 years
• WBC >16,000/mm³
• Blood glucose >200 mg/dL
• LDH >350 IU/L
• AST/SGOT >250 IU/L

• Hematocrit decrease >10%
• BUN rise >5 mg/dL
• Serum calcium <8 mg/dL
• PaO2 <60 mmHg
• Base deficit >4 mEq/L
• Fluid sequestration >6L

• Mild: No organ failure, no local/systemic complications
• Moderately severe: Transient organ failure (<48h) OR local complications
• Severe: Persistent organ failure (>48h), single or multi-organ

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DIAGNOSIS

1. Typical abdominal pain (epigastric, radiating to back)
2. Serum lipase and/or amylase ≥3x upper limit of normal
3. Confirmatory findings on cross-sectional imaging (CT/MRI)

Differential Diagnosis

• Perforated peptic ulcer
• Acute cholecystitis / biliary colic
• Intestinal obstruction
• Mesenteric vascular occlusion
• Renal colic
• Inferior wall MI
• Dissecting aortic aneurysm
• Diabetic ketoacidosis

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COMPLICATIONS

Local Complications (Revised Atlanta)

Systemic Complications

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MANAGEMENT

I. General Principles (Conservative - First Line)

II. Fluid Resuscitation

• Most critical initial intervention
• Aggressive IV fluid therapy: isotonic crystalloids (Normal Saline or Lactated Ringer's preferred)
• Rate: 250-500 mL/hour initially, guided by urine output (>0.5 mL/kg/hr), HR, BP, CVP
• Hypovolemic shock: main cause of death in first 48 hours
• Monitor with Swan-Ganz catheter in elderly/severe cases

III. Analgesia

• Pethidine (meperidine) 50-100 mg - drug of choice
• Morphine is traditionally avoided - causes spasm of sphincter of Oddi, increases pancreatic ductal pressure
• NSAIDs, epidural analgesia for refractory pain

IV. Nasogastric Aspiration

• Continuous NG suction: removes HCl, prevents hormonal stimulation of pancreatic secretion, relieves vomiting

V. Oxygen Therapy

• Oxygen by mask/nasal prongs if PaO2 <70 mmHg
• Intubation and mechanical ventilation if progressive hypoxia/ARDS

VI. Nutritional Support

• Mild AP: Resume oral feeds when pain resolves and patient is hungry (usually 3-7 days)
• Severe AP: Enteral feeding preferred over parenteral nutrition (fewer infectious complications, lower cost)
  • Nasojejunal (NJ) tube preferred; nasogastric (NG) may be equally effective in most patients
  • Enteral route maintains gut mucosal integrity, reduces bacterial translocation
• Early bland, high-calorie diet during recovery; avoid large meals

VII. Antibiotics

• NOT routinely indicated in mild AP
• Indicated for: infected necrosis, abscess, cholangitis, bacteremia
• Prophylactic antibiotics: controversial; not recommended routinely (current guidelines)
• Pye's Surgical Handicraft: broad-spectrum (e.g., cefoperazone) for 3-5 days as prophylaxis in severe disease
• Carbapenems (imipenem) have good pancreatic penetration for infected necrosis

VIII. Management of Specific Causes

• Gallstone pancreatitis:
  • ERCP + sphincterotomy if coexisting cholangitis or biliary obstruction
  • Early laparoscopic cholecystectomy (within 3 days in mild AP) = standard of care
  • Without cholecystectomy: ERCP + sphincterotomy to prevent recurrence
• Hypertriglyceridemia: Plasmapheresis, insulin infusion, fibrates
• Alcohol: Cessation, thiamine

IX. Management of Complications

• Pseudocyst: Small/asymptomatic - observe; symptomatic/large - endoscopic drainage (cyst-gastrostomy), surgical drainage
• Infected necrosis / Abscess: Antibiotics + drainage (percutaneous CT-guided, endoscopic necrosectomy, or surgical)
• Walled-off necrosis (WON): Step-up approach - percutaneous drain → endoscopic necrosectomy → open surgery (only if others fail)
• Hypocalcemia: IV calcium gluconate
• Hyperglycemia: Insulin infusion
• ARDS: Mechanical ventilation, PEEP
• AKI: Dialysis if refractory

X. Surgical Indications

1. Uncertain diagnosis with suspected other acute abdomen (perforated peptic ulcer, appendicitis)
2. Pancreatic abscess - surgical drainage
3. Infected pancreatic necrosis - not responding to conservative measures
4. Hemorrhagic complications
5. Severity predicted by Ranson's/Imrie criteria: guide timing of intervention

Recovery Phase

• Most patients recover spontaneously in several days
• Gradually replace NG suction and IV fluids with oral feeding
• Restart with bland, high-calorie diet; avoid large meals and alcohol
• Investigate and treat underlying cause to prevent recurrence

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PROGNOSIS

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SUMMARY TABLE

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