Biliary colic and cholecystitis are in the spectrum of biliary tract disease. This spectrum ranges from asymptomatic gallstones to biliary colic, cholecystitis, choledocholithiasis, and cholangitis.
Gallstones can be divided into 2 categories: Cholesterol stones (80%) and pigment stones (20%). Most patients with gallstones are asymptomatic. Stones may temporarily obstruct the cystic duct or pass through into the common bile duct, leading to symptomatic biliary colic, which develops in 1-4% of patients with gallstones annually.
Cholecystitis occurs when obstruction at the cystic duct is prolonged (usually several hours) resulting in inflammation of the gallbladder wall. Acute cholecystitis develops in approximately 20% of patients with biliary colic if they are left untreated.
However, the incidence of acute cholecystitis is falling, likely due to increased acceptance by patients of laparoscopic cholecystectomy as a treatment of symptomatic gallstones.
Choledocholithiasis occurs when the stone becomes lodged in the common bile duct, with the potential sequelae of cholangitis and ascending infections.
Biliary sludge is a reversible suspension of precipitated particulate matter in bile in a viscous mucous liquid phase. The most common precipitates are cholesterol monohydrate crystals and various calcium-based crystals, granules, and salts.
A portion of biliary sludge contains comparatively large particles (1-3 mm) called microliths, the formation of which is an intermediate step in the formation of gallstones (about 12.5%).
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