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Acute Pancreatitis & Gallstone Disease — Complete Reference

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PART 1: GALLSTONE DISEASE

1.1 Normal Gallbladder Anatomy

• Fundus – the rounded, blind end projecting below the liver edge
• Body – the main part
• Infundibulum (Hartmann's pouch) – a small pouch near the neck where stones frequently lodge
• Neck – narrows into the cystic duct

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1.2 Calot's Triangle

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1.3 Cystic Duct Variations (Surgically Important)

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1.4 Gallstone Disease — Basics

1. Bile supersaturated with cholesterol
2. Gallbladder hypomotility
3. Accelerated crystal nucleation
4. Mucus hypersecretion — traps crystals → macroscopic stones

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1.5 Complications of Gallstone Disease

1. Biliary colic – transient cystic duct obstruction by stone → episodic RUQ pain
2. Acute cholecystitis – sustained obstruction → gallbladder inflammation; RUQ pain >6 hours, fever, Murphy's sign positive
3. Chronic cholecystitis – recurrent inflammation → wall thickening, fibrosis; Rokitansky-Aschoff sinuses on histology
4. Choledocholithiasis – stone passes into CBD → obstructive jaundice, elevated bilirubin/ALP
5. Cholangitis (ascending) – bacterial infection of biliary tree; Charcot's triad: RUQ pain + fever + jaundice; Reynold's pentad adds hypotension + altered consciousness
6. Gallstone pancreatitis – stone impacted at ampulla of Vater → pancreatitis
7. Gallstone ileus – stone erodes through GB wall into bowel → intestinal obstruction (usually at terminal ileum)
8. Mirizzi syndrome – stone in Hartmann's pouch compresses CHD externally
9. Gallbladder carcinoma – associated with porcelain gallbladder, large stones

— Robbins Pathologic Basis of Disease; Sleisenger & Fordtran's GI and Liver Disease

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1.6 Gallbladder Duplication — Types & Importance

• Duplication can be missed on USG — mistaken for a fold or septum
• MRCP or HIDA scan is most useful for diagnosis
• Both gallbladders MUST be removed during cholecystectomy — failure to remove the second one leads to ongoing symptoms, recurrent cholecystitis, or biliary complications
• Each cystic duct must be individually identified, clipped, and divided to avoid bile leak
• The anomalous cystic duct arrangement increases risk of CBD injury

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PART 2: ACUTE PANCREATITIS

2.1 Definition

1. Acute onset of severe, persistent epigastric pain, often radiating to the back
2. Serum amylase or lipase ≥3× the upper limit of normal
3. Characteristic findings on imaging (CECT, MRI, or USG)

— Sabiston Textbook of Surgery; Current Surgical Therapy 14e

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2.2 Causes (Etiology)

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2.3 Mechanism of Pancreatitis (Pathophysiology)

1. Trigger (gallstone, alcohol, etc.) → injury to acinar cells
2. Trypsinogen is converted to trypsin intracellularly (normally prevented by SPINK1 inhibitor)
3. Active trypsin activates other zymogens: chymotrypsin, elastase, phospholipase A2, kallikrein
4. Autodigestion of pancreatic parenchyma, fat necrosis, vascular injury
5. Local inflammation → release of TNF-α, IL-1, IL-6 → systemic inflammatory response
6. In severe disease → SIRS → ARDS → multiorgan failure → death

• Obstructive theory: Stone lodges at the ampulla of Vater → obstruction of both CBD and pancreatic duct → intraductal pressure rises → enzyme activation
• Reflux theory: Impacted stone creates a common channel → bile refluxes into pancreatic duct → bile salts cause direct acinar cell necrosis by raising cytoplasmic Ca²⁺

— Sabiston Textbook of Surgery, Current Surgical Therapy 14e

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2.4 Gallstone Migration and Ampullary Obstruction

• Most gallstones causing pancreatitis are microlithiasis (<5 mm)
• Small stones pass through the cystic duct → enter the CBD → migrate distally
• At the ampulla of Vater, the stone either:
  • Passes into the duodenum (most cases — transient obstruction, mild AP)
  • Becomes impacted → sustained obstruction → severe biliary pancreatitis
• Elevated ALT >3× normal in the context of AP has >95% positive predictive value for gallstone etiology
• Combined elevation of transaminases + pancreatic enzymes + gallstones on USG has 97% sensitivity, 100% specificity for acute biliary pancreatitis

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2.5 Clinical Features (Symptoms)

• Epigastric or periumbilical pain: constant, severe, radiates to the back in a "band-like" pattern; NOT relieved by posture (key feature)
• Pain is often worse lying supine, slightly relieved by sitting forward (knee-chest position)
• Nausea and vomiting (90% of patients) — does NOT relieve the pain (distinguishes from other causes)
• Anorexia, fever, abdominal distension (ileus)
• In severe AP: tachycardia, hypotension, diaphoresis, altered mental status, respiratory distress

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2.6 Signs on Physical Examination

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PART 3: INVESTIGATIONS

3.1 Serum Amylase

• Rises within 2–12 hours of onset, peaks at 24 hours, normalizes within 3–5 days
• Half-life: ~10 hours (shorter than lipase)
• Diagnostic threshold: ≥3× the upper limit of normal
• Limitation: Not specific — elevated in peptic ulcer disease, parotitis, cholecystitis, mesenteric ischemia, renal failure, salpingitis, macroamylasemia
• May be normal in alcoholic pancreatitis (chronic underlying disease) or hypertriglyceridemia-induced AP

3.2 Serum Lipase

• Rises within 4–8 hours, peaks at 24 hours, normalizes in 8–14 days
• More sensitive and more specific than amylase for AP
• Preferred marker in patients presenting >24–48 hours after symptom onset (amylase may have normalized)
• Also elevated in renal failure, peptic ulcer, but less so than amylase
• Current preferred diagnostic marker for AP

3.3 Liver Function Tests (LFT) in Gallstone Pancreatitis

• Combined elevation of ALT + amylase/lipase + USG showing gallstones: 97% sensitivity, 100% specificity for acute biliary pancreatitis

3.4 Other Lab Findings in AP

• WBC: Leukocytosis (inflammation/infection)
• Hematocrit: Elevated (hemoconcentration from third-spacing; a rising Hct is a poor prognostic sign)
• BUN: Elevated (prerenal azotemia from dehydration)
• Blood glucose: Elevated (decreased insulin secretion)
• Calcium: May be decreased (saponification with fat necrosis — poor prognostic sign)
• CRP: Peaks at 48–72 hours; >150 mg/L defines severe AP (cannot be used on admission)
• LDH: Elevated in severe disease

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3.5 Ultrasound Abdomen (USG)

• First-line imaging in all AP patients
• Utility for pancreatitis diagnosis limited due to overlying bowel gas and intra-abdominal fat
• Primary purpose: Detect gallstones, GB wall thickening, pericholecystic fluid, biliary ductal dilatation
• Sensitivity for gallstones: ~95%
• Findings in cholecystitis: GB wall >3 mm, pericholecystic fluid, sonographic Murphy's sign (tenderness under ultrasound probe — PPV >90% for acute cholecystitis when gallstones also present)
• May show edematous, enlarged pancreas in AP

3.6 CECT Abdomen (Contrast-Enhanced CT)

• Gold standard for evaluating severity of AP and its complications
• Not required for diagnosis if clinical and biochemical criteria are met
• Indications for CECT:
  • Diagnostic uncertainty
  • Failure to improve with conservative management
  • Clinical deterioration
  • Confirmation of suspected necrosis or complications
• Best phase: Portal venous phase (65–70 seconds post-contrast) to evaluate:
  • Viable vs. necrotic pancreatic parenchyma
  • Peripancreatic inflammation and fluid collections
  • Vascular complications
• Timing: Ideally 48–72 hours after symptom onset (necrosis takes time to declare itself)
• CT Severity Index (CTSI / Balthazar Score):

• 0–3: Mild (mortality <3%)
• 4–6: Moderate
• 7–10: Severe (mortality up to 17%, morbidity ~92%)

3.7 MRCP (Magnetic Resonance Cholangiopancreatography)

• Non-invasive visualization of the biliary and pancreatic ductal anatomy
• No radiation, no contrast needed for duct imaging
• Primary use in pancreatitis:
  • Evaluate for choledocholithiasis (CBD stones) — sensitivity comparable to ERCP
  • Evaluate pancreatic duct anatomy: pancreas divisum, strictures, anomalies
  • Work up of unexplained or recurrent pancreatitis
• Secretin-stimulated MRCP: IV secretin causes transient pancreatic duct dilatation → better visualization of subtle ductal anatomy and functional evaluation
• NOT indicated in the acute setting for initial management — role is pre-operative planning and recurrence workup
• Advantage over ERCP: no procedural risk of post-ERCP pancreatitis

— Current Surgical Therapy 14e; Sabiston Textbook of Surgery

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PART 4: SEVERITY SCORING

4.1 Ranson's Criteria

• Age >70, WBC >18,000, glucose >220, LDH >400, AST >250 (at admission)
• After 48h: Hct ↓>10%, Ca <8, base deficit >5, BUN ↑>2, fluids >4 L; PaO₂ not used

• <3: Mild — mortality <1%; negative predictive value ~90%
• ≥3: Severe — mortality significantly increases
• ≥6: Very severe — mortality approaches 50%
• Limitation: Can only be fully calculated at 48 hours; low positive predictive value (~50%)

4.2 BISAP Score (Bedside Index of Severity in Acute Pancreatitis)

• Score 0: Mortality <1%
• Score ≥3: Mortality >5%; high risk of organ failure and pancreatic necrosis

4.3 SIRS Criteria (Currently Recommended)

• Temperature >38.3°C or <36°C
• Heart rate >90 bpm
• Respiratory rate >20/min or PaCO₂ <32 mmHg
• WBC >12,000/mL, <4,000/mL, or >10% band forms

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PART 5: MANAGEMENT OF ACUTE PANCREATITIS

5.1 Fluid Resuscitation

• Cornerstone of management — patients are hypovolemic due to vomiting, third-spacing into retroperitoneum
• Preferred fluid: Lactated Ringer's (LR) over normal saline — meta-analysis shows decreased odds of SIRS with LR (OR 0.38)
• Starting rate: 5–10 mL/kg/hour (goal-directed) per IAP/APA guidelines
• Targets (resuscitation endpoints):
  • Heart rate <120 bpm
  • Mean arterial pressure 65–85 mmHg
  • Urine output >0.5 mL/kg/hour
  • Hematocrit 35–44%
  • BUN decreasing
• WATERFALL Trial (2022): Aggressive resuscitation (20 mL/kg bolus + 3 mL/kg maintenance) caused fluid overload in 21% of patients — trial stopped early. Moderate resuscitation is now favored.
• Avoid over-resuscitation → acute lung injury, abdominal compartment syndrome
• Avoid under-resuscitation → pancreatic necrosis, end-organ damage

5.2 Analgesia

• Adequate pain control is essential — undertreated pain increases stress response
• IV opioids are acceptable and effective (historically withheld due to concern about Sphincter of Oddi spasm with morphine — this concern is outdated and not evidence-based)
• Options:
  • Hydromorphone or fentanyl (preferred IV opioids)
  • Patient-controlled analgesia (PCA) for severe pain
  • NSAIDs (ibuprofen, diclofenac) may be used adjunctively in mild-moderate cases
  • Epidural analgesia in selected severe cases
• Meperidine (pethidine) was historically preferred but is now less used due to seizure risk with repeated doses

5.3 NPO (Nil Per Os — Nothing by Mouth) Concept

• Traditional teaching: Keep patient NPO until pain resolves and enzymes normalize → to avoid stimulating an inflamed pancreas
• Current evidence: Early feeding is beneficial and safe
• Current recommendation (IAP/APA, ACG):
  • Mild AP: Begin oral feeding as tolerated as soon as nausea/vomiting resolves (often within 24–48 hours)
  • Typically start with a soft, low-fat diet rather than clear liquids — no significant difference in outcomes but soft diet better tolerated and reduces hospital stay
  • Severe AP / unable to eat: Start enteral nutrition via nasogastric or nasojejunal tube within 24–48 hours — do NOT wait for ileus to resolve
  • Enteral > parenteral nutrition: Enteral nutrition maintains gut mucosal barrier, reduces bacterial translocation, reduces infectious complications
  • TPN (parenteral nutrition) only when enteral route is completely contraindicated

5.4 Antibiotics — Indications

• Prophylactic antibiotics are NOT recommended in AP — large RCTs and meta-analyses have failed to show benefit in preventing infectious complications or reducing mortality in sterile necrosis
• Antibiotics ARE indicated for:
  1. Infected pancreatic necrosis (confirmed or strongly suspected)
  2. Ascending cholangitis complicating gallstone pancreatitis
  3. Other concurrent infections (pneumonia, UTI, bacteremia)
• Antibiotics that penetrate pancreatic necrosis:
  • Carbapenems (imipenem/meropenem) — first choice
  • Quinolones (ciprofloxacin) + metronidazole
  • High-dose cephalosporins (3rd generation)
  • Piperacillin-tazobactam
• Infected necrosis should be suspected: persistent fever, leukocytosis, sepsis, or clinical deterioration after 7–10 days of illness.

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PART 6: COMPLICATIONS OF ACUTE PANCREATITIS

6.1 Pancreatic Necrosis

• Nonviable pancreatic parenchyma or peripancreatic fat — occurs in ~20% of AP
• On CECT: areas of low attenuation (<40–50 HU) that do not enhance with contrast (normal: 100–150 HU)
• Risk of infection directly proportional to extent:
  • <30% necrosis: 22% infection risk
  • 30–50%: 37%

  • 50%: 46%

• Organisms: enteric gram-negative rods (E. coli, Klebsiella, Pseudomonas), Enterococcus
• Infected necrosis → indication for drainage + antibiotics; surgery if needed

6.2 Fluid Collections (Atlanta Classification)

6.3 ARDS and Systemic Complications

• Pancreatic inflammation triggers release of TNF-α, IL-1, phospholipase A2 → systemic effects
• ARDS: Phospholipase A2 degrades surfactant → alveolar collapse → hypoxia
• Other systemic complications:
  • Acute kidney injury (prerenal/intrinsic)
  • Cardiovascular collapse (hypovolemia + cytokines)
  • Coagulopathy/DIC
  • Hypocalcemia (fat saponification)
  • Hyperglycemia (islet cell destruction)
  • Left pleural effusion (pancreaticopleural fistula — see vascular complications)

6.4 Vascular Complications

• Pseudoaneurysm: Pancreatic elastase erodes vessel walls → most common: splenic artery; also cystic artery, GDA, SMA
• Splenic vein thrombosis → splenomegaly, gastric varices, GI bleeding → managed conservatively; persistent bleeding requires splenectomy

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PART 7: SURGICAL MANAGEMENT

7.1 Timing of Cholecystectomy in Gallstone Pancreatitis

• In the absence of treatment, 30% of patients with biliary pancreatitis will have recurrent disease within weeks to months.

7.2 Laparoscopic Cholecystectomy — Key Points

• Standard of care for symptomatic gallstone disease and gallstone pancreatitis
• Four-port approach: umbilical camera port, epigastric working port, two right lateral ports
• Critical View of Safety (CVS): Before clipping any structures, the dissection must reveal only two structures entering the gallbladder neck — the cystic duct and the cystic artery. The hepatocystic triangle must be cleared of fat and fibrous tissue.
• Intraoperative cholangiography (IOC) recommended when CBD anatomy is uncertain or when CBD stones suspected
• Main risks: CBD injury (0.3–0.5%), bile leak, vascular injury, port-site hernia
• Converted to open if anatomy is unclear, dense adhesions, hemorrhage, or suspected CBD injury

7.3 ERCP — Indications in Gallstone Pancreatitis

1. Ascending cholangitis (Charcot's triad or Reynold's pentad) — urgent ERCP + sphincterotomy + stone extraction
2. Persistent CBD obstruction confirmed by persistent jaundice, rising bilirubin, dilated CBD on imaging (EUS/MRCP), or failure to improve
3. Severe AP with suspected persistent biliary obstruction and inability to perform early cholecystectomy

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PART 8: DIFFERENCE — ACUTE vs. CHRONIC PANCREATITIS

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PART 9: DIAGNOSIS OF GALLBLADDER DUPLICATION

• Both gallbladders carry risk of stone formation, cholecystitis, and cancer
• Leaving one behind leads to persistent symptoms and future need for re-operation
• Identification of both cystic ducts and ensuring both are clipped is essential to prevent bile leak

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Sources: Sabiston Textbook of Surgery (9780443124341); Current Surgical Therapy 14e (9780323796835); Robbins & Cotran Pathologic Basis of Disease (9780443264528); Sleisenger & Fordtran's GI and Liver Disease (9780323609623); Harrison's Principles of Internal Medicine 22E (9781265977061)You've run out of free credits. Sign up for a free account to continue using Orris.