Page 2 - 05- Cholelithiasis

CHOLELITHIASIS
Hongyi Cui, MD, PhD

BASICS

DESCRIPTION
The presence of cholesterol, pigment, or mixed stones (calculi) within the gallbladder
Synonym(s): gallstones

Pediatric Considerations
Uncommon in children <10 years
Most gallstones in children are pigment stones associated with blood dyscrasias.
EPIDEMIOLOGY
Incidence
Increased in Native Americans and Hispanics
Increases with age ~1–3% per year; peaks at 7th decade
2% of the U.S. population develops gallstones annually.

Prevalence
8–10% of the U.S. population with gallstones
20% >65 years of age
Female > male (2 to 3:1)

ETIOLOGY AND PATHOPHYSIOLOGY
Gallstone formation is a complex process mediated by genetic, metabolic, immune, and
environmental factors. Gallbladder sludge (a mixture of cholesterol crystals, calcium
bilirubinate granules, and mucin gel matrix) serves as the nidus for gallstone formation.
Bile supersaturated with cholesterol (cholesterol stones) precipitates as microcrystals that
aggregate and expand. Stone formation is enhanced by biliary stasis or impaired gallbladder
motility.
Decrease in bile phospholipid (lecithin) or decreased bile salt secretion
Excess unconjugated bilirubin in patients with hemolytic diseases; passage of excess bile salt
into the colon with subsequent absorption of excess unconjugated bilirubin in patients with
inflammatory bowel disease (IBD) or after distal ileal resection (black or pigment stones)
Hydrolysis of conjugated bilirubin or phospholipid by bacteria in patients with biliary tract
infection or stricture (brown stones or primary bile duct stones; rare in the Western world and
common in Asia)

RISK FACTORS
Age peaks in patients 60 to 80 years of age.
Female gender, pregnancy, multiparity, obesity, and metabolic syndrome
Caucasian, Hispanic, or Native American descent
High-fat diet rich in cholesterol
Cholestasis or impaired gallbladder motility in association with prolonged fasting, long-term
total parenteral nutrition (TPN), following vagotomy, long-term somatostatin therapy, and