Acute Pancreatitis

Overview

• Acute inflammation of the pancreas
• Mortality rate: 10-25%
• Occurs due to abnormal activation of pancreatic enzymes
• Results in pancreatic damage

Pancreas Functions

Endocrine

• Release substances into the blood:
  • Insulin
  • Glucagon
  • Somatostatin

Exocrine

• Secretion of pancreatic juice into the duodenum via the pancreatic duct
  • Contains bicarbonate to neutralize stomach acid
  • Contains digestive enzymes:
    • Trypsinogen (breaks down proteins)
    • Elastase
    • Lipase (breaks down fats)
    • Amylase (breaks down carbohydrates)

Pathophysiology

• In acute pancreatitis, trypsinogen is activated to trypsin within the pancreas
• Leads to inflammation, edema, vascular injury, ischemia, and necrosis
• Mild Pancreatitis: Primarily inflammation (termed interstitial edematous pancreatitis)
• Severe Pancreatitis: Predominantly necrosis (termed necrotizing pancreatitis)

Causes (Mnemonic: I GET SMASHED)

• Idiopathic
• Gallstones (most common cause)
• Ethanol/Alcohol (second most common cause globally)
• Trauma
• Steroids
• Microbial Infections (e.g., mumps, hepatitis, tuberculosis)
• Autoimmune Pancreatitis
• Scorpion Stings
• Hypercalcemia/Hypertriglyceridemia
• Endoscopic Retrograde Cholangiopancreatography (ERCP)
• Emboli
• Drugs (e.g., diuretics, opiates, valproic acid, estrogen preparations)

Signs and Symptoms

• Abdominal Pain: Mostly epigastric, radiates to the back, described as band-like
• Nausea and Vomiting
• Loss of Appetite
• Fever
• Features of Gallstone Disease (if gallstone-caused)
• Examination Findings:
  • Epigastric tenderness
  • Rebound tenderness, distension and guarding (severe cases)
  • Cullen's sign (bruising around umbilicus)
  • Grey Turner's sign (bruising around flanks)

Secondary Manifestations due to Inflammatory Response

• Shock (due to capillary permeability)
• Acute Respiratory Distress Syndrome
• Disseminated Intravascular Coagulation
• Multi-System Organ Failure

Diagnosis

• Requires 2 out of 3 criteria:
  1. Abdominal pain
  2. Elevated lipase or amylase levels (3x the upper reference range for amylase)
  3. Imaging findings indicative of acute pancreatitis
• Imaging: Ultrasound or CT (more informative after 48 hours)
• Other Investigations:
  • Liver function tests (common cause: gallstones)
  • Hypocalcemia (due to free fatty acids binding calcium)
  • Hypoglycemia (damage to islets of Langerhans)

Prognostic Scoring: Glasgow-Imrie Score (Mnemonic: PANCREAS)

• P: PaO2 <8 kPa
• A: Age >55
• N: Neutrophils (Leukocytosis >15x10^9/L)
• C: Calcium <2mmol/L (<8mg/dL)
• R: Renal Function (Raised Blood Urea Nitrogen)
• E: Enzymes (LDH >600 IU/L or AST >200 IU/L)
• A: Albumin <32g/L
• S: Sugar (Hyperglycemia >10mmol or >180mg/dL)
• Each parameter scores one point; higher score indicates higher mortality risk

Treatment

• Identify and Correct Underlying Cause (e.g., ERCP for gallstones)
• Supportive Care:
  • Fluids: Large volumes required, strict monitoring, catheterization
  • Analgesia: Opioids, paracetamol
  • Nutrition: Nasogastric tube for enteral feeding
• Antibiotics: Not routine, started if infection suspected
• Surgical Indications:
  • Infected pancreatic necrosis
  • Pancreatic pseudocyst, abscess, obstruction, vascular complications
  • Diagnostic uncertainty