Gallstone disease
Cholelithiasis refers to the presence of gallstones in the gallbladder, while choledocholithiasis refers to gallstones in the common bile duct. Gallstone disease refers to various clinical manifestations of the presence of gallstones, including:
- Uncomplicated gallstone disease
- Complicated gallstone disease
Complicated gallstone disease refers to the presence of gallstone-related complications, mentioned above. Complicated gallstone disease may present with biliary colic. If biliary colic is present without gallstone-related complications, the condition is called uncomplicated gallstone disease.
The majority of gallstones are asymptomatic (and therefore not considered as gallbladder disease) and are discovered incidentally on imaging. Gallstones exist in 10 – 15% of the Western population, but only 1 – 4% become symptomatic.
Risk factors for gallstone disease
The risk factors for the two different stones are different. For cholesterol stones:
- 6 Fs
- Fat (obesity)
- Female
- Fertile (multiparity or pregnancy)
- Forty (above 40 years of age)
- Fair-skinned (Caucasian)
- Family history
- Gallbladder stasis
For pigment stones:
- Chronic haemolytic anaemias
- Billiary infection
- Gastrointestinal disorders
- Crohn disease
- Ileal resection
- Cystic fibrosis with pancreatic insufficiency.
Pathology
Two types of stones exist. The most common type is the cholesterol stone, which accounts for 80% of all stones in the west. Bile formation is the only significant pathway for the body to eliminate excess cholesterol, either as free cholesterol or as bile salts. Cholesterol is dissolved in bile. The solution gets supersaturated if the cholesterol concentration exceeds the solubilization capacity of the bile.
Cholesterol won’t crystallize out of the solution until there is a nucleus, a “starting point” that it can precipitate onto. This nucleation process is then followed by growth, as more and more cholesterol precipitate into the nucleus, causing the stone to grow in size. Biliary stasis is also essential for the development of a stone.
It should be noted that most cholesterol stones aren’t comprised of only cholesterol. They most commonly also contain some bilirubin-calcium or palmitate-calcium salts. Pure cholesterol stones are rare.
The second type of stone is the pigment stone, which is primarily comprised of bilirubin-calcium salts. These usually occur in association with chronic haemolysis, which increases the production of bilirubin.
Cholesterol stones arise exclusively in the gallbladder and are yellowish. Pigment stones may arise anywhere in the biliary tree and are black or brownish.
Diagnosis and evaluation
Leukocytosis is often present in cholecystitis and cholangitis. An afebrile patient with biliary colic and normal inflammatory parametres likely has uncomplicated gallstone disease. Elevated liver enzymes, bilirubin, or jaundice is suspicious for choledocholithiasis.
Ultrasound is the most sensitive imaging modality for detecting gallbladder stones and evaluating the biliary tree.
Abdominal CT may be used to rule out certain complicated gallstone diseases, like gangrenous cholecystitis, gallbladder perforation, emphysematous cholecystitis, or gallstone ileus. CT cannot visualise the stones themselves well.