45. Cholelithiasis. Cholecystitis.

Definition:

• Cholelithiasis: Formation of gallstones in the gallbladder.
• Choledocholithiasis: Presence of gallstones in the common bile duct (CBD).
• Biliary colic: Sudden episodic pain due to temporary obstruction of the cystic duct by a gallstone.

Types of Stones:

• Cholesterol stones: Yellow, radiolucent (most common in Western countries); often solitary or few.
• Pigment stones:
• Black: Associated with hemolysis (e.g. chronic hemolytic anemia).
• Brown: Associated with infection or biliary stasis.

Etiology / Risk Factors:

• Multifactorial origin, mainly involving:
• Supersaturation of bile with cholesterol (↓ solubility).
• Impaired gallbladder motility (↓ contraction, e.g. pregnancy, fasting).
• Stasis and mucin hypersecretion (acts as a nucleating agent).
• Risk factors:
• Female, Fat, Forty, Fertile, Fair
• Estrogen (pregnancy, OCPs), obesity, rapid weight loss, diabetes
• Hemolytic anemia (bilirubin stones)
• Family history, liver disease

Pathogenesis:

• Bile supersaturated with cholesterol → crystallization → stone formation
• Decreased gallbladder motility or biliary stasis → retention of crystals → growth of stones

Symptoms:

• Often asymptomatic (especially with small stones)
• Biliary colic:
• Sudden, severe RUQ or epigastric pain lasting 1–6 hours, often after fatty meals
• May radiate to the right shoulder or back
• Nausea, vomiting, bloating, indigestion
• If stone obstructs CBD → possible jaundice, cholangitis, or pancreatitis