What is the initial workup and management for acute pancreatitis?

Initial Workup and Management of Acute Pancreatitis

The initial workup for acute pancreatitis should include serum lipase (preferred over amylase), complete blood count, metabolic panel, liver function tests, triglycerides, calcium, and abdominal ultrasound within 24 hours, followed by appropriate fluid resuscitation with Lactated Ringer's solution and early enteral nutrition. 1, 2, 3

Diagnosis

Diagnostic Criteria

• Diagnosis requires at least 2 of 3 criteria:
  1. Abdominal pain consistent with pancreatitis
  2. Serum lipase and/or amylase >3 times upper limit of normal
  3. Characteristic findings on abdominal imaging 4

Laboratory Testing

• Serum lipase is the preferred diagnostic test with higher sensitivity and a longer diagnostic window than amylase 2
• Additional essential labs:
  • Complete blood count (CBC)
  • Comprehensive metabolic panel (CMP)
  • Liver function tests (LFTs)
  • Serum triglycerides
  • Calcium level 1, 3

Imaging

• Transabdominal ultrasound within 24 hours to determine etiology (especially biliary) 1
• Contrast-enhanced CT (CE-CT) or MRI indicated:
  • When diagnosis is uncertain
  • In severe cases, 72-96 hours after symptom onset
  • Not necessary for mild cases with clear etiology 1, 3

Severity Assessment

Risk Stratification

• Perform severity stratification within 48 hours using:
  • APACHE II score
  • Clinical assessment
  • Body mass index (BMI)
  • Presence of pleural effusion on chest radiograph 1
  • Neutrophil-to-lymphocyte ratio (NLR) has good accuracy (76%) for predicting severity 5

Classification

• Revised Atlanta Classification defines severity:
  • Mild: No organ failure or local/systemic complications
  • Moderately severe: Transient organ failure (<48h) and/or local complications
  • Severe: Persistent organ failure (>48h) 4
• Patients with persistent organ failure and infected necrosis have highest mortality risk 4

Initial Management

Fluid Resuscitation

• Moderate fluid resuscitation with Lactated Ringer's solution (preferred over normal saline)
• Avoid aggressive fluid resuscitation which can increase risk of fluid overload 1, 6
• Goal-directed, non-aggressive hydration approach 6

Pain Management

• Begin with non-opioid medications (e.g., acetaminophen)
• Progress to opioids if inadequate pain control
• Consider patient-controlled analgesia (PCA) for severe cases 1

Nutrition

• Early enteral nutrition within 24-72 hours of admission
• Target: 25-35 kcal/kg/day and 1.2-1.5 g/kg/day protein
• Nasojejunal tube feeding with elemental or semi-elemental formula for patients unable to tolerate oral intake
• Total parenteral nutrition only if enteral nutrition not tolerated 1, 6

Antibiotics

• Do not use prophylactic antibiotics routinely
• Consider antibiotics only for:
  • Infected necrosis (confirmed by image-guided FNA)
  • Cholangitis
  • Other extrapancreatic infections 1, 6
• Limit antibiotic prophylaxis to 14 days or less in cases of substantial pancreatic necrosis (>30% of gland) 1

Management of Complications

Local Complications

• For patients with >30% pancreatic necrosis or clinical suspicion of sepsis:
  • Perform image-guided fine needle aspiration (FNA) for culture 7-14 days after onset 1
• Step-up approach for infected necrosis:
  1. Percutaneous catheter drainage
  2. Endoscopic drainage
  3. Minimally invasive surgical necrosectomy
  4. Open surgical necrosectomy as last resort 1, 7

Biliary Pancreatitis Management

• For mild pancreatitis: Cholecystectomy within 2 weeks after discharge, preferably during same admission
• For severe pancreatitis: Delay cholecystectomy until resolution of lung injury and systemic disturbance 1
• Urgent ERCP (within 24h) only for patients with gallstone pancreatitis and concomitant cholangitis 6

Specialized Care

• Patients with severe acute pancreatitis should be admitted to ICU whenever possible 4
• Refer patients with extensive necrotizing pancreatitis to specialist units 1

Common Pitfalls to Avoid

1. Ordering both amylase and lipase (lipase alone is sufficient) 2
2. Aggressive fluid resuscitation (can worsen outcomes) 1, 6
3. Routine use of prophylactic antibiotics (not recommended) 1, 6
4. Delaying enteral nutrition (should be started early) 1, 6
5. Performing ERCP in gallstone pancreatitis without cholangitis 6
6. Delaying cholecystectomy in mild gallstone pancreatitis 1