1. Acute Pancreatitis

 

 

Overview

  • Definition: Inflammation of the exocrine pancreas, ranging from mild oedema to severe necrosis and systemic inflammation.

  • Incidence: 

    • UK: 15–42 cases/100,000/year, rising by 2.7% annually.

    • Mortality: 1–7% (up to 20% in necrosis).

Aetiology

  • Primary causes: 

    • UK: Gallstones (75%) > Alcohol.

    • Global: Alcohol most common.

  • Other causes: Drugs (e.g., corticosteroids, azathioprine), trauma, hypercalcemia, hypertriglyceridemia, infections, autoimmune conditions.

Pathophysiology

  • Key mechanisms: 

    • Acinar cell injury → Premature trypsin activation.

    • Ethanol increases pancreatic ductal pressure and enzymatic activation.

    • Calcium transients potentiate enzymatic activity.

  • Complications: Pancreatic necrosis, vascular leakage, systemic inflammatory response.

Diagnostic Approach

Criteria (2 of 3 required):

  1. Typical abdominal pain.

  2. Serum amylase/lipase > 3× upper limit of normal.

  3. Imaging (CT/MRI/US) consistent with AP.

Laboratory Investigations

  • Markers: 

    • Elevated lipase/amylase (supportive, not definitive).

    • Elevated ALT > 150 IU/L indicates gallstone pancreatitis.

    • C-reactive protein: Inflammation severity.

Imaging

  • Preferred initial test: Ultrasound for gallstones.

  • CT: 

    • After 48 hours if clinical deterioration.

    • Identifies necrosis, abscesses.

  • MRI/MRCP: Better for biliary obstructions and soft tissue resolution.

Prognostication in Acute Pancreatitis (AP)

Prognostication is critical to determine severity, predict complications, and guide management.

Systemic Inflammatory Response Syndrome (SIRS)

  • Definition: 

    • Criteria: ≥2 of the following: 

      • Temperature <36°C or >38°C.

      • Heart rate >90 bpm.

      • Respiratory rate >20 breaths/min or PaCO₂ <32 mmHg.

      • WBC count <4×10⁹/L or >12×10⁹/L.

    • Persistent SIRS (>48 hours) is associated with: 

      • Mortality: ~25%.

      • Higher risk of organ failure.

APACHE II (Acute Physiology and Chronic Health Evaluation II)

  • Parameters: 

    • Physiological variables: Temperature, heart rate, MAP, pH, sodium, potassium, creatinine, hematocrit, WBC count.

    • Age.

    • Chronic health points (e.g., comorbidities).

  • Scoring: 

    • 8 indicates severe AP with a high risk of mortality.

  • Strengths: 

    • Applicable at admission.

  • Limitations: 

    • Complexity; requires detailed data.

Ranson’s Criteria

  • Parameters: Separate for admission and 48 hours. 

    • At Admission: 

      • Age >55 years.

      • WBC count >16×10⁹/L.

      • Glucose >200 mg/dL (11.1 mmol/L).

      • LDH >350 IU/L.

      • AST >250 IU/L.

    • At 48 Hours: 

      • Hematocrit drop >10%.

      • BUN increase >5 mg/dL.

      • Calcium <8 mg/dL.

      • PO₂ <60 mmHg.

      • Base deficit >4 mEq/L.

      • Fluid sequestration >6 L.

  • Scoring: 

    • ≥3 criteria = severe AP.

Modified Glasgow Score (Imrie Score)

  • Parameters (PANCREAS mnemonic): 

    • PaO₂ <8 kPa.

    • Age >55 years.

    • Neutrophilia: WBC count >15×10⁹/L.

    • Calcium <2 mmol/L.

    • Renal function: Urea >16 mmol/L.

    • Enzymes: LDH >600 IU/L, AST >200 IU/L.

    • Albumin <32 g/L.

    • Sugar: Glucose >10 mmol/L.

  • Scoring: 

    • ≥3 indicates severe AP.

Bedside Index for Severity in Acute Pancreatitis (BISAP)

  • Parameters: 

    • BUN >25 mg/dL.

    • Impaired mental status (GCS <15).

    • SIRS present.

    • Age >60 years.

    • Pleural effusion.

  • Scoring: 

    • Each criterion = 1 point; total score out of 5.

    • ≥3 indicates high mortality risk.

Management

Initial Treatment

  • Resuscitation: 

    • IV fluids (e.g., Ringer’s lactate) at 5–10 mL/kg/hour.

    • Analgesics (opiates).

    • Antiemetics.

  • Monitoring: 

    • Blood glucose, arterial oxygenation, and acid-base status.

    • Urine output to guide fluid therapy.

Severe Pancreatitis

  • Supportive Care: 

    • High-dependency unit admission.

    • Insulin for strict glucose control.

    • Correction of hypocalcemia and hypomagnesemia.

  • Antibiotics: 

    • Not recommended in non-infected pancreatitis.

    • Indicated for proven infection of necrosis.

Collections in Severe Pancreatitis

Types of Collections

  1. Acute Peripancreatic Fluid Collections (APFCs): 

    • Develop <4 weeks after onset.

    • Typically contain only fluid and lack a defined capsule.

    • Often resolve spontaneously without intervention.

  2. Acute Necrotic Collections (ANCs): 

    • Contain both liquid and necrotic debris.

    • Develop <4 weeks after onset.

  3. Walled-Off Necrosis (WON): 

    • Develops >4 weeks post-onset as a mature encapsulated collection.

    • Contains necrotic debris and fluid.

  4. Pancreatic Pseudocysts: 

    • Encapsulated, fluid-only collections.

    • Occur >4 weeks post-onset and lack solid necrotic debris.

Indications for Intervention

  • Symptomatic collections causing pain, infection, or obstruction.

  • Infected necrosis diagnosed by imaging or clinical signs (e.g., fever, leukocytosis).

  • Persistent unresolving collections.

Management Approaches

  1. Observation: 

    • Asymptomatic collections can be monitored without immediate intervention.

  2. Drainage Techniques: 

    • Endoscopic drainage: 

      • Preferred for WON and pseudocysts when anatomically accessible.

      • Use of lumen-apposing metal stents (LAMS) is common.

    • Percutaneous drainage: 

      • Suitable for collections not accessible endoscopically.

      • Can serve as a bridge to surgical management if needed.

    • Surgical necrosectomy: 

      • Reserved for severe, refractory cases where other methods fail.

      • Minimally invasive approaches are preferred over open surgery.

Nutrition

  • Mild AP: 

    • Reintroduce diet as pain subsides.

  • Severe AP: 

    • Early enteral feeding (nasogastric or nasojejunal).

    • Avoid parenteral feeding unless enteral goals unmet.

Special Considerations

Alcohol-Induced Pancreatitis

  • Prophylaxis for Withdrawal: 

    • Benzodiazepines, thiamine, folic acid.

  • Prevention: 

    • Outpatient follow-up to reduce recurrence.

Gallstone Pancreatitis

  • Cholecystectomy: 

    • Mild AP: Within the same admission or 2 weeks post-discharge.

    • Severe AP: Delayed until inflammation resolves.

References

  1. Goodchild G, et al. Practical Guide to the Management of Acute Pancreatitis. Frontline Gastroenterology, 2019. Read Full Text

  2. Roberts SE, Akbari A, et al. The incidence of acute pancreatitis. Aliment Pharmacol Ther, 2013.

  3. Banks PA, Bollen TL, et al. Classification of acute pancreatitis--2012. Gut, 2013.