Acute Pancreatitis — 10-Mark Answer

Definition

1. Abdominal pain consistent with the disease
2. Serum amylase or lipase >3× the upper limit of normal
3. Characteristic findings on abdominal imaging

Etiology (Causes) — "GET SMASHED"

Pathophysiology

• Autodigestion of pancreatic parenchyma and peripancreatic fat
• Release of pro-inflammatory cytokines (IL-1, IL-6, TNF-α) → systemic inflammatory response
• In severe cases: parenchymal necrosis, fat necrosis, hemorrhage, and multisystem organ failure

Clinical Features

• Severe, sudden-onset epigastric pain radiating to the back ("boring" pain)
• Pain worsens in supine position; relieved by leaning forward
• Nausea, vomiting, anorexia
• Fever

• Epigastric tenderness, guarding, rigidity
• Cullen's sign — periumbilical ecchymosis (haemorrhagic pancreatitis)
• Grey-Turner's sign — flank ecchymosis
• Paralytic ileus, abdominal distension
• Jaundice (if biliary obstruction)

Investigations

Serum Enzymes

• Serum lipase — preferred marker; rises and falls more slowly than amylase; more specific
• Serum amylase — rises within 6–12 hours, returns to normal in 3–5 days; can be elevated in other conditions (e.g., salivary gland disease, perforated PUD)
• >3× ULN of either confirms diagnosis

Imaging

• Ultrasound abdomen — first-line; detects gallstones, biliary dilation, peripancreatic fluid
• CT abdomen with contrast — gold standard for severity assessment; detects necrosis, abscesses, pseudocysts

CT scan showing dilated pancreatic duct in stone pancreatitis — Textbook of Family Medicine 9e

Other Tests

• LFTs (ALT >3× ULN suggests gallstone etiology)
• Serum triglycerides, calcium
• CBC, CRP, BUN, creatinine
• Blood glucose
• Chest X-ray (pleural effusion, ARDS)
• MRCP — for bile duct anatomy without radiation

Severity Assessment

Ranson's Criteria

BISAP Score (Bedside Index of Severity in AP)

• BUN >25 mg/dL
• Impaired mental status (Glasgow Coma Scale <15)
• SIRS (≥2 SIRS criteria)
• Age >60 years
• Pleural effusion

Atlanta Classification (Revised 2012)

• Mild AP — no organ failure, no local/systemic complications; resolves in 1 week
• Moderately Severe AP — transient organ failure (<48 h) or local complications
• Severe AP — persistent organ failure (>48 h), single or multi-organ

Complications

Local Complications

• Acute peripancreatic fluid collection (early, <4 weeks)
• Pancreatic pseudocyst (>4 weeks, non-epithelialized fluid collection)
• Acute necrotic collection (contains necrotic material, <4 weeks)
• Walled-off necrosis (WON) (organized necrosis, >4 weeks)
• Pancreatic abscess
• Pseudoaneurysm, splenic vein thrombosis

Systemic Complications

• ARDS (acute respiratory distress syndrome)
• Acute kidney injury
• Shock
• DIC (disseminated intravascular coagulation)
• Hypocalcemia (saponification of fat)
• Hyperglycemia
• GI bleeding

Management

General Principles (first 48–72 hours are critical)

1. IV Fluid Resuscitation — Most critical early intervention
   • Aggressive isotonic fluid replacement (Ringer's lactate preferred over normal saline — reduces SIRS)
   • Target urine output >0.5 mL/kg/hr
   • Monitor for fluid overload
2. Analgesia
   • IV opioids (morphine, hydromorphone, meperidine) — adequate pain control is essential
   • NSAIDs/ketorolac for mild cases
3. NPO vs. Early Oral/Enteral Feeding
   • Mild AP: resume clear liquids and advance diet when pain resolves and bowel sounds return
   • Severe AP: early enteral nutrition via nasojejunal tube (preferred over TPN) — reduces bacterial translocation and infection
   • TPN only if enteral route not tolerated
4. Antibiotics
   • Not indicated prophylactically
   • Used only when there is evidence of infected necrosis or sepsis
   • Agents: imipenem, meropenem, or ciprofloxacin + metronidazole
5. Monitoring
   • Frequent vitals, urine output, CBC, metabolic panel
   • ICU admission for severe AP

Specific Interventions

• Gallstone pancreatitis: Early ERCP with sphincterotomy if cholangitis or persistent biliary obstruction; cholecystectomy during same admission for mild AP to prevent recurrence
• Hypertriglyceridemia: Plasmapheresis, insulin infusion (activates lipoprotein lipase)
• Infected necrosis: Endoscopic or surgical necrosectomy (step-up approach: drainage first, then necrosectomy)

Prognosis & Mortality

Key Points Summary

• AP = autodigestion by premature enzyme activation
• Most common causes: gallstones > alcohol
• Diagnose with 2 of 3 criteria (pain + enzymes + imaging)
• Lipase is more sensitive and specific than amylase
• Severity: Ranson's, BISAP, Atlanta Classification
• Management: aggressive IV fluids, analgesia, early enteral feeding; antibiotics only for infected necrosis
• Gallstone AP → ERCP if obstruction → cholecystectomy before discharge
• Complications: pseudocyst, necrosis, ARDS, renal failure, hypocalcemia