What is the management approach for infectious pancreatitis?

Management of Infectious Pancreatitis

Antibiotic therapy should be administered only to treat confirmed infected pancreatic necrosis, not as prophylaxis for sterile necrosis, with targeted broad-spectrum antibiotics that penetrate pancreatic tissue. 1

Diagnosis of Infected Pancreatic Necrosis

Laboratory Assessment

• Procalcitonin (PCT) is the most sensitive laboratory test for detecting pancreatic infection, with low serum values being strong negative predictors of infected necrosis 1
• Other markers include:
  • Increasing leukocyte and platelet counts
  • Deranged clotting
  • Elevated C-reactive protein (CRP)
  • Biochemical features of multiple organ failure 1

Imaging

• CT with IV contrast is the primary imaging modality 1
• Gas in the retroperitoneal area on CT strongly suggests infection but is present in only a limited number of cases 1
• MRI and endoscopic ultrasound (EUS) are alternative options 1

Microbiological Confirmation

• CT-guided fine-needle aspiration (FNA) for Gram stain and culture can confirm infection and guide antibiotic therapy, though it's no longer in routine use due to high false negative rates 1
• Blood cultures should be obtained if sepsis is suspected 1

Antibiotic Treatment

When to Start Antibiotics

• Antibiotics should be started when infection is:
  1. Confirmed by positive culture
  2. Strongly suspected based on clinical deterioration, gas in collection, bacteremia, or sepsis 2
• Routine prophylactic antibiotics are not recommended for sterile necrosis 1, 3

Antibiotic Selection

• Use antibiotics with good pancreatic tissue penetration:
  • First-line options: Carbapenems (meropenem 1g q6h, imipenem/cilastatin 500mg q6h) 1
  • Alternative options for patients without MDR risk factors:
    • Doripenem 500mg q8h by extended infusion
    • Meropenem/vaborbactam or ceftazidime/avibactam + metronidazole for MDR risk 1
  • For beta-lactam allergy: Eravacycline 1mg/kg q12h 1

Duration of Treatment

• Immunocompetent, non-critically ill patients: 4 days if source control is adequate 1
• Immunocompromised patients: Up to 7 days based on clinical condition and inflammatory markers 1
• Ongoing signs of infection beyond 7 days warrant diagnostic investigation and multidisciplinary re-evaluation 1

Source Control

Timing of Intervention

• Delay drainage and debridement for 4 weeks when possible to allow necrotic tissue to become demarcated 2
• Immediate drainage has not shown superiority over postponed drainage in terms of complications 4
• Patients with postponed drainage strategy require fewer invasive interventions 4

Drainage Approaches

1. Percutaneous drainage:

   • Consider in early acute period (<2 weeks) for infected or symptomatic collections
   • Useful for patients too ill for endoscopic or surgical intervention 2

2. Endoscopic transmural drainage:

   • Preferred first-line approach for walled-off pancreatic necrosis (WON)
   • Self-expanding metal stents appear superior to plastic stents 2

3. Direct endoscopic necrosectomy:

   • Reserved for patients who don't respond to transmural drainage alone
   • Should be performed at referral centers with necessary expertise 2

4. Surgical debridement:

   • Minimally invasive approaches preferred over open necrosectomy
   • Options include videoscopic-assisted retroperitoneal debridement, laparoscopic transgastric debridement
   • Open surgical debridement reserved for cases not amenable to less invasive procedures 2

Supportive Care

Nutritional Support

• Early enteral nutrition is recommended to decrease risk of infected necrosis 2
• Oral feeding can be started immediately if there's no nausea/vomiting 3
• When oral nutrition isn't feasible, use enteral nutrition via nasogastric/duodenal or nasojejunal tube 3
• Parenteral nutrition should only be considered if enteral feeds aren't tolerated after 5-7 days 3

Fluid Resuscitation

• Early aggressive intravenous hydration is most beneficial within first 12-24 hours 5
• Moderate fluid resuscitation approach provides better outcomes with fewer complications 3

Special Considerations

Biliary Pancreatitis

• ERCP with sphincterotomy is indicated for severe gallstone pancreatitis with persistent symptoms beyond 48 hours, acute cholangitis, or persistent biliary obstruction 3
• Should be performed as soon as possible in patients with acute biliary pancreatitis and common bile duct obstruction 1

Antifungal Therapy

• Routine prophylactic antifungal administration is not recommended 1
• Consider antifungal therapy only in high-risk patients for intra-abdominal candidiasis 1

Pitfalls and Caveats

• Avoid early surgical debridement (first 2 weeks) as it's associated with increased morbidity and mortality 2
• Asymptomatic fluid collections should not be drained due to risk of introducing infection 1
• Avoid routine prophylactic antibiotics as they may contribute to antibiotic resistance without providing benefits 3
• CT-guided FNA should be performed cautiously as there is evidence it may introduce infection 1