Gallstones

Gallstones are calculi formed in the gallbladder or bile duct (1).

• there is usually a small core of organic material, often containing bacteria. The main part of the stone is made up of concentric layers, suggesting that it is formed by a series of discrete precipitation events
• only 20% are radio-opaque (2).

Classically, gallstones are divided into 3 main types:

• cholesterol stones
• pigment stones (brown/black)
• mixed stones

NB: cholesterol and mixed stones consist of 51–99% pure cholesterol plus an admixture of calcium salts, bile acids, bile pigments and phospholipids (3).

The typical patient is said to be the "fair, fat, fertile, female of forty", but many gallstone patients do not fit this description.

Factors which precipitate gallstone formation include:

• excessive bile cholesterol
• low bile salt levels
• decreased gallbladder motility
• decreased phosphatidylcholine molecule (which prevents the crystallisation of cholesterol) (1)

Aapproximately 15% of the adult population are thought to have gallstone disease, and most of these people experience no symptoms (4)

• for a small proportion of people with gallstone disease, the stones irritate the gallbladder or block part of the biliary system, and this can cause symptoms such as pain, infection and inflammation
• if these symptoms are left untreated, gallstones can cause more serious and in some cases life-threatening conditions such as cholecystitis, cholangitis, pancreatitis and jaundice

Reference:

• (1) Gurusamy KS, Davidson BR. Gallstones. BMJ. 2014;348:g2669
• (2) Croton R. The basics – The management of gallstones. GPonline 2011
• (3) Bailey and Love’s, Short practice of surgery.
• (4) NICE (October 2014).Gallstone disease