Gallstone (cholelithiasis)

Summary

Gallstones (cholelithiasis) represent the most common biliary pathology, affecting 10-20% of adults in developed countries. These crystalline deposits form within the gallbladder through precipitation of bile constituents - primarily cholesterol (75%) or bilirubin. While most gallstones remain asymptomatic, approximately 20-30% will eventually cause symptoms, most commonly biliary colic - episodic RUQ pain lasting <6 hours triggered by fatty meals.

Definition

• Cholelithiasis: Formation of stones within the gallbladder
• Pathophysiology: Imbalance between cholesterol/bilirubin and solubilizing factors (bile salts, lecithin) → precipitation → stone formation
• Location:
  • Gallbladder (cholelithiasis) - most common
  • Common bile duct (choledocholithiasis)
  • Intrahepatic ducts (rare)

Epidemiology

• Prevalence: 10-20% of adults in developed countries
• Gender: Female > Male (2-3:1)
• Age: Increases with age, especially after 40 years
• Geography: Higher in Western countries, Native Americans, Hispanics
• Risk factors mnemonic: The 6 F's
  • Fat (obesity)
  • Female
  • Fertile (multiparity)
  • Forty (age > 40)
  • Fair-skinned
  • Family history

Types of Gallstones

• Cholesterol stones (80%)
  • Pure cholesterol: ~10%, single, large, yellow
  • Mixed stones: ~70%, multiple, contain cholesterol + calcium salts
  • Risk factors: obesity, female sex, pregnancy, drugs (fibrates, OCPs)
• Pigment stones (20%)
  • Black pigment stones:
    • Calcium bilirubinate polymers
    • Associated with hemolysis (sickle cell, thalassemia)
    • Also seen in cirrhosis
  • Brown pigment stones:
    • Calcium bilirubinate + fatty acids
    • Associated with infections (E. coli, parasites)
    • Common in Asia

Etiology / Risk Factors

1. Cholesterol Stones
   • Increased cholesterol secretion:
     • Obesity, high-fat diet
     • Pregnancy, estrogen therapy, OCPs
     • Genetics (ABCG5/G8 mutations)
   • Decreased bile acids:
     • Terminal ileal disease/resection
     • Cholestyramine use
     • Fibrates (inhibit cholesterol 7α-hydroxylase)
   • Gallbladder stasis:
     • Pregnancy, TPN, rapid weight loss
     • Octreotide, fasting
     • Vagotomy, diabetes
2. Black Pigment Stones
   • Composed of calcium bilirubinate polymer + calcium salts
   • Chronic hemolysis → ↑ unconjugated bilirubin
   • Cirrhosis → ↓ bilirubin conjugation
   • Gilbert syndrome
3. Brown Pigment Stones
   • Made of calcium bilirubinate, palmitate, and stearate, often mixed with cholesterol
   • Most common in Asia; form in ducts due to infection
   • β‑glucuronidase from bacteria (E. coli, Klebsiella) deconjugates bilirubin → precipitation → stone formation
   • Associated with bile stasis, infection, stents, parasites (Clonorchis, Ascaris)

Clinical Presentation

• Asymptomatic (70-80%)
  • Incidental finding on imaging
  • Annual risk of symptoms: 1-2%
  • Usually no treatment needed
• Biliary colic (20-30%)
  • Pain characteristics:
    • Nocturnal, constant, NOT colicky (despite the name)
    • RUQ or epigastric pain
    • Radiation to right shoulder/scapula
    • Duration: 30 min - 6 hours
  • Triggers: Fatty meals, large meals
  • Associated symptoms: Nausea, vomiting
  • Physical exam: RUQ tenderness, no fever

Diagnosis

• Laboratory tests
  • Usually NORMAL in uncomplicated cholelithiasis
  • CBC, LFTs, amylase/lipase → to rule out complications

• Imaging
  • RUQ Ultrasound (first-line):
    • Sensitivity > 95% for stones > 2mm
    • Shows hyperechoic foci with acoustic shadowing
    • Can detect sludge and GB wall thickening
  • CT scan:
    • Poor for gallstones (only 15-20% are radiopaque)
    • Better for complications
  • MRCP:
    • If ultrasound inconclusive
    • Excellent for CBD stones

Management

• Asymptomatic gallstones
  • Expectant management (observation)
  • Prophylactic cholecystectomy ONLY if:
    • Porcelain gallbladder
    • Gallstones ≥ 3 cm
    • Gallbladder polyps ≥ 1 cm
    • Planning bariatric surgery
    • Chronic hemolytic anemia (children)
• Symptomatic gallstones
  • Acute management:
    • NSAIDs (ketorolac) - first line
    • Opioids if NSAIDs contraindicated
    • Antiemetics, IV fluids
  • Definitive treatment:
    • Laparoscopic cholecystectomy = GOLD STANDARD
    • Timing: elective, within 6 weeks
• Non-surgical options (if surgery contraindicated)
  • Ursodeoxycholic acid
    • Only for small (<1cm), radiolucent stones
    • Success rate: 30-50%
    • High recurrence (50% at 5 years)

Complications

• Acute cholecystitis: Persistent cystic duct obstruction → inflammation → fever + Murphy sign
• Choledocholithiasis: CBD stone → jaundice + ↑ ALP/bilirubin
• Cholangitis: CBD obstruction + infection → Charcot triad (pain + fever + jaundice)
• Biliary pancreatitis: Stone at ampulla → ↑ lipase/amylase
• Gallstone ileus: Fistula → bowel obstruction (rare)
• Mirizzi syndrome: Cystic duct stone compressing CHD
• Gallbladder cancer: Rare (< 1%)

Summary Table