Acute Pancreatitis

Acute Pancreatitis: Definition & Etiology - Pancreas Ablaze!

• Definition: Acute inflammatory process of the pancreas, typically reversible, with variable involvement of regional tissues or remote organ systems.
• Etiology:
  • Gallstones (most common, ~40-50%)
  • Alcohol (~30-40%)
  • 📌 I GET SMASHED mnemonic:
    • Idiopathic
    • Gallstones
    • Ethanol
    • Trauma
    • Steroids
    • Mumps/Malignancy
    • Autoimmune (e.g., IgG4-related)
    • Scorpion sting
    • Hypercalcemia/Hypertriglyceridemia (Triglycerides > 1000 mg/dL)
    • ERCP
    • Drugs (e.g., azathioprine, valproate, thiazides)

⭐ Gallstones and alcohol together account for approximately 70-80% of acute pancreatitis cases in most populations.

oka

Acute Pancreatitis: Pathophysiology - Enzyme Mayhem

• Core: Pancreatic autodigestion by prematurely activated enzymes in acinar cells.
• Initiation & Enzyme Cascade:
  • Critical event: Intra-acinar activation of trypsinogen to trypsin.
  • Trypsin activates other zymogens:
    • Proelastase $\rightarrow$ Elastase (vessel/tissue damage).
    • Prophospholipase A2 $\rightarrow$ Phospholipase A2 (membrane damage).
• Pathological Consequences:
  • Acinar cell injury and necrosis.
  • Local inflammation and cytokine release (TNF-α, IL-1, IL-6), leading to systemic effects (SIRS).
  • Fat necrosis via saponification: $Ca^{2+} + \text{fatty acids} \rightarrow \text{calcium soaps}$; may cause hypocalcemia.

⭐ The critical initiating event in acute pancreatitis is the intra-acinar activation of trypsinogen to trypsin.

Acute Pancreatitis: Clinical & Diagnosis - Spotting the Flames

• Symptoms: Acute, severe, persistent epigastric pain radiating to back; relieved by leaning forward. Nausea, vomiting.
• Signs:
  • Epigastric tenderness, guarding.
  • Severe: Tachycardia, hypotension, jaundice.
  • ⚠️ Cullen's sign (periumbilical ecchymosis), Grey Turner's sign (flank ecchymosis) → retroperitoneal hemorrhage, severe disease, poor prognosis.
• Diagnosis (Revised Atlanta Criteria - Need 2 of 3):
  1. Characteristic abdominal pain.
  2. Serum amylase and/or lipase ≥ 3x ULN.
  3. Characteristic imaging findings (CECT, MRI, USG).
• Labs:
  • Lipase: More sensitive & specific than amylase, remains ↑ longer.
  • CRP: ↑ indicates severity.

  ⭐ Serum lipase is preferred over amylase for diagnosing acute pancreatitis due to its higher specificity and longer duration of elevation.

• Imaging:
  • USG Abdomen: Initial (to detect gallstones).
  • CECT: Best for diagnosis confirmation (if unclear), assessing severity (e.g., necrosis), and detecting complications (usually 48-72 hours after onset if indicated).

Acute Pancreatitis: Severity & Complications - Gauging the Inferno

• Revised Atlanta Classification:
  • Mild: No organ failure, no local/systemic complications.
  • Moderately Severe: Transient organ failure (<48h) OR local/systemic complications (no persistent organ failure).
  • Severe: Persistent organ failure (>48h).
• Severity Scoring:
  • BISAP (Bedside Index of Severity in Acute Pancreatitis): 1 point each for:
    • BUN >25 mg/dL
    • Impaired mental status (GCS <15)
    • SIRS (≥2 criteria)
    • Age >60 years
    • Pleural Effusion
    • Score ≥3 indicates ↑ mortality.
  • Others: Ranson's criteria, APACHE II.
• Local Complications:
  • Acute Peripancreatic Fluid Collection (APFC)
  • Pancreatic Pseudocyst (>4 wks, encapsulated fluid, defined wall)
  • Acute Necrotic Collection (ANC)
  • Walled-Off Necrosis (WON) (>4 wks, encapsulated necrosis ± debris)
  • Infected necrosis (critical)
  • Pancreatic abscess
• Systemic Complications:
  • SIRS, ARDS, AKI
  • Cardiovascular collapse/shock, DIC
  • Metabolic: Hypocalcemia (saponification), Hyperglycemia

⭐ Hypocalcemia (serum Ca < 8 mg/dL or ionized Ca < 1.0 mmol/L) indicates severe disease and poor prognosis.

High‑Yield Points - ⚡ Biggest Takeaways

• Gallstones and alcohol abuse are the leading causes of acute pancreatitis.
• Characterized by severe epigastric pain, often radiating to the back, with nausea and vomiting.
• Elevated serum lipase (more specific) and amylase are crucial for diagnosis.
• Ranson's criteria and APACHE II score are used to assess severity and prognosis.
• Major complications include pancreatic pseudocyst, necrosis, ARDS, and hypocalcemia (saponification).
• Sentinel loop on X-ray and Grey Turner's/Cullen's signs indicate severe disease.