Gallstones: cholesterol vs pigment
- Lesion
Gallstones form when bile has too much cholesterol or bilirubin; most cause no symptoms, but they can block ducts and inflame the gallbladder.
What it is
Gallstones (cholelithiasis) are very common. Cholesterol stones form when bile is supersaturated with cholesterol, gallbladder motility is reduced, nucleation is accelerated and mucus traps crystals. Pigment stones contain calcium bilirubinate: black stones form in sterile bile with chronic hemolysis or cirrhosis, brown stones in infected bile ducts. Most stones are silent; complications include cholecystitis, choledocholithiasis, cholangitis, pancreatitis and gallbladder cancer.
Step by step
- The liver secretes more cholesterol into bile, or fewer bile acids and phospholipids to keep it dissolved.
- Bile becomes supersaturated with cholesterol.
- The gallbladder empties poorly (stasis), so bile stays concentrated longer.
- Cholesterol crystals nucleate; mucin from the gallbladder wall traps them as sludge.
- Crystals grow into stones that may block the cystic or common bile duct.
Cholesterol vs pigment gallstones
| Feature | Cholesterol stones | Black pigment stones | Brown pigment stones |
|---|---|---|---|
| Composition | Mostly crystalline cholesterol | Calcium bilirubinate polymers, calcium salts | Calcium bilirubinate with fatty acid soaps |
| Site | Gallbladder | Gallbladder | Intrahepatic and extrahepatic ducts |
| Setting | Female sex, obesity, estrogens, rapid weight loss, age | Chronic hemolysis, cirrhosis, ileal disease | Bile duct infection, parasites, stasis |
| Appearance | Pale yellow, hard, faceted; mostly radiolucent | Small, black, many; often radiopaque | Soft, greasy, brown; radiolucent |
Clinical notes
- Biliary colic: post-prandial right upper quadrant pain from a stone impacting the cystic duct.
- Complications: acute cholecystitis, choledocholithiasis with jaundice, ascending cholangitis, gallstone pancreatitis, gallstone ileus, gallbladder carcinoma.
Test yourself
Think of the answer, then tap the question to see it.
Which four conditions favour cholesterol gallstones?
Supersaturation of bile with cholesterol, gallbladder hypomotility, accelerated crystal nucleation and mucus hypersecretion.
Why do patients with sickle cell disease form gallstones?
Chronic hemolysis increases unconjugated bilirubin in bile, which precipitates as calcium bilirubinate (black pigment stones).
Where do brown pigment stones typically form?
In infected intrahepatic and extrahepatic bile ducts, often with bacteria or parasites.
Elsewhere in DurgiPedia
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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Gallstones (Cholelithiasis) (StatPearls (NCBI Bookshelf), 2026); Choledocholithiasis (StatPearls (NCBI Bookshelf), 2026).
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Representative model, for educational purposes only.