Gallstones

• Cholelithiasis


  Formation of gallstones
• Cholelithiasis


  • From the Greek chol-(bile)+lith-(stone)+iasis (formation)
  • Formation of calculi is known as lithiasis
  • A calculus (plural calculi) is a stone (a concretion of material, usually mineral salts)
• Bile

  • 85% water
  • 10% bile salts
  • 3% mucus and pigments
  • 1% fats, and 0.7% inorganic salts
• Micelle


  • An aggregate of surfactant molecules dispersed in a liquid colloid
  • In aqueous solution forms an aggregate with the hydrophilic head regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre
• Primary bile salts


  • Cholic acid (Cholate)
  • Chenodeoxycholic acid (Chenodeoxycholate)
• Secondary bile salts


  • Deoxycholic acid (Deoxycholate)
  • Lithocholic acid (Lithocholate)
• Enterohepatic circulation


  90% of bile salts are reabsorbed
• Types of gallstones


  • Cholesterol (cholesterol content >50%, 70 –90 % are cholesterol stones)
  • Pigment stones (calcium bilirubinate) - Brown
  • Pigment stones (calcium bilirubinate) - Black
  • Mixed stones
• Cholesterol stones


  • Often solitary & radiolucent
  • 70% to 80% of all gallstones in western countries
• Black pigment stones


  • Haemolytic conditions (sickle cell anaemia, thalassaemia, hereditory spherocytosis) or cirrhosis
• Brown pigment stones


  • Soft, earthy brown stones
  • Found in the CBD
  • Due to stasis and infection
  • Most common in Asia
• Risk factors for gallstones

  • Gender - more in female
  • Age - incidence increases with increased age
  • Diet - A diet high in fat and cholesterol
  • Obesity
  • Rapid weight loss
  • Haemolytic states
  • Total Parenteral nutrition
  • Ileal resection
  • Hormone replacement treatment - estrogen
• Diagnostic tests for gallstones

  • Plain AXR (10% yield)
  • Ultrasound - diagnostic investigation of choice
  • CTAP/ MRI
  • HIDA scan
• HIDA scan


  • 99Tcm-labelled hepatic iminodiacetic acid scan
  • Administered IV, and excretion into the gall bladder measured
  • If no isotope detected in the gall bladder after 4 hours some sort of biliary obstruction must be present
  • If the isotope fills the gall bladder, a fatty meal or cholecystokinin is administered to force gall bladder contraction
  • An ejection fraction >40% represents normal function
• Normal HIDA scan - Acute cholecystitis: no filling of GB
• Gallstones are common and becoming more common
• 40% people who are 40yo have gallstones
• 60% people who are 80yo have gallstones
• Less than 10% of people with gallstones will develop complications because of the gallstones