What are the diagnostic criteria and treatment options for acute pancreatitis?

Acute Pancreatitis Diagnosis

Diagnose acute pancreatitis when at least 2 of 3 criteria are met: characteristic epigastric abdominal pain radiating to the back, serum lipase or amylase ≥3 times the upper limit of normal, and imaging findings consistent with pancreatitis. 1, 2, 3

Diagnostic Criteria

Clinical Presentation

• Upper abdominal pain with radiation to the back is the hallmark symptom, typically accompanied by nausea and vomiting 4
• Epigastric or diffuse abdominal tenderness on examination 4
• Rarely, body wall ecchymoses (Cullen's sign at umbilicus, Grey-Turner's sign in flanks) may be present in severe cases 4

Laboratory Markers

Lipase is the preferred diagnostic enzyme over amylase due to higher sensitivity (79% vs 72%) and a longer diagnostic window (remains elevated 8-14 days vs 3-7 days for amylase). 4, 1, 5

• Lipase ≥3 times upper limit of normal is diagnostic when combined with appropriate clinical context 4, 1, 5
• Lipase rises within 4-8 hours of pancreatic injury and peaks at 24 hours 1, 5
• Amylase ≥4 times upper limit of normal can be used if lipase is unavailable, though less specific 4
• Amylase peaks at approximately 48 hours after symptom onset 5

Important caveat: Amylase can be elevated in non-pancreatic conditions including renal disease, appendicitis, acute cholecystitis, bowel obstruction, head injuries, and hepatic injuries. 5

Imaging Studies

Ultrasound should be performed initially in all patients to detect gallstones, free peritoneal fluid, biliary duct dilation, and exclude other pathology such as abdominal aortic aneurysm. 4, 5 However, the pancreas is poorly visualized in 25-50% of cases, so ultrasound cannot definitively confirm or exclude pancreatitis. 4

Contrast-enhanced CT is the diagnostic standard for radiologic evaluation when clinical and biochemical findings are inconclusive. 4, 2

• CT should be performed after 72 hours of illness onset to avoid underestimating pancreatic necrosis 5
• Earlier CT (within first 72 hours) is indicated for patients with predicted severe disease (APACHE II >8) or evidence of organ failure 5
• CT is essential for patients with persisting organ failure, signs of sepsis, or clinical deterioration 6-10 days after admission 4, 5

MRI and endoscopic ultrasound (EUS) are alternative imaging modalities when CT is contraindicated or additional detail is needed. 4

Baseline Investigations

Chest and abdominal plain radiographs should be obtained routinely to provide baseline assessment and exclude other pathology such as perforated viscus, intestinal obstruction, or leaking abdominal aortic aneurysm. 4

The correct diagnosis should be made within 48 hours of admission to avoid missing alternative life-threatening intra-abdominal catastrophes. 4

Severity Assessment

Prognostic Scoring Systems

APACHE II score is the preferred prognostic tool, with a cutoff of >8 indicating severe disease requiring intensive monitoring. 1, 5

Glasgow score ≥3 or C-reactive protein >150 mg/L at 48 hours also predict severe disease and complications. 4, 1, 5

Persisting organ failure after 48 hours in hospital is a critical indicator of severe acute pancreatitis. 4, 1

Laboratory Markers for Severity

• Procalcitonin (PCT) is the most sensitive laboratory test for detection of pancreatic infection, and low serum values are strong negative predictors of infected necrosis 4
• Increased white blood cell count and C-reactive protein support severity assessment 4
• Clinical assessment alone is unreliable and will misclassify approximately 50% of patients 5

Important caveat: The severity of acute pancreatitis is independent of the degree of enzyme elevation—elevated amylase/lipase <3 times normal doesn't exclude severe disease. 5

Essential Etiologic Work-Up

Serum triglycerides should be measured if gallstones are absent and no significant alcohol history exists, as levels >1000 mg/dL (>11.3 mmol/L) indicate hypertriglyceridemia as the etiology. 5, 3

Liver function tests help identify biliary etiology and assess disease severity. 5

Serum calcium levels should be checked to identify hypercalcemia as a potential cause. 5

Management Based on Severity

Mild Acute Pancreatitis

• Regular diet and advance as tolerated 4
• Pain control with oral medications 4
• Routine vital signs monitoring 4

Moderately Severe Acute Pancreatitis

• Enteral nutrition (oral, nasogastric, or nasojejunal) is preferred; parenteral nutrition only if enteral not tolerated 4
• IV pain medications 4
• IV fluids to maintain hydration 4
• Monitor hematocrit, blood urea nitrogen, creatinine 4
• Continuous vital signs monitoring 4

Severe Acute Pancreatitis

• All patients should be managed in high dependency unit or intensive care unit with full monitoring and systems support 4
• Enteral nutrition (oral, nasogastric, or nasojejunal) is strongly preferred over parenteral nutrition 4
• Nasogastric route for feeding is effective in 80% of cases 4
• IV pain medications 4
• Early aggressive fluid resuscitation 4, 6
• Mechanical ventilation if needed 4

Antibiotic Use

Routine prophylactic antibiotics are NOT recommended for all patients with acute pancreatitis, as they are not associated with significant decrease in mortality or morbidity. 4

Antibiotics are indicated only for treating infected acute pancreatitis, confirmed by:

• PCT elevation 4
• CT- or EUS-guided fine-needle aspiration (FNA) for Gram stain and culture 4

For infected necrotizing pancreatitis in immunocompetent patients without MDR colonization:

• Meropenem 1 g q6h by extended infusion or continuous infusion 4
• Doripenem 500 mg q8h by extended infusion 4
• Imipenem/cilastatin 500 mg q6h by extended infusion 4

Antibiotic duration should not exceed 14 days if used. 4

Biliary Pancreatitis Management

Urgent ERCP should be performed within 72 hours in patients with acute biliary pancreatitis who have cholangitis, jaundice, dilated common bile duct, or predicted/actual severe pancreatitis. 4

All patients undergoing early ERCP for severe gallstone pancreatitis require endoscopic sphincterotomy whether or not stones are found. 4

Definitive management of gallstones should occur during the same hospital admission or within 2 weeks to prevent recurrence. 4

Common Pitfalls to Avoid

• Do not rely on enzyme levels to monitor disease progression or determine timing of oral feeding—use clinical parameters instead (resolution of pain, tolerance of oral intake, absence of systemic inflammatory signs). 5
• Do not delay CT imaging in deteriorating patients while waiting for enzyme levels to change. 5
• Do not perform CT too early (within 72 hours) as it may underestimate pancreatic necrosis. 5
• Do not use ultrasound alone to definitively diagnose or exclude pancreatitis due to poor pancreatic visualization in 25-50% of cases. 4
• Do not assume normal lipase excludes pancreatitis if presentation is very early (<4 hours) or very late (>14 days). 1, 5