sludge is a common term for an abnormality of bile seen with ultrasonography of the gallbladder. specifically the bile within the gallbladder is seen to be of two different densities with the denser bile on the bottom. the bile is denser because it contains microscopic particles usually cholesterol or pigment embedded in mucus. (the mucus is secreted by the gallbladder). over time sludge may remain in the gallbladder it may disappear and not return or it may come and go. these particles may be precursors of gallstones and they occur often in some situations in which gallstones frequently appear for example rapid weight loss pregnancy and with prolonged fasting. nevertheless it appears that sludge goes on to become gallstones in only a minority of people. it is not clear how often -- if at all -- sludge alone causes problems. sludge has been blamed for many of the same symptoms as gallstones -- biliary colic cholecystitis and pancreatitis but often these symptoms and complications are caused by very small gallstones that are missed by ultrasonography. it is also possible that these gallstone-like symptoms and complications are actually caused by small gallstones that have passed through the ducts and into the intestine rather than the sludge itself. thus there is uncertainty about the meaning of sludge. but it is clear that sludge is not the equivalent of gallstones. the practical implication of this uncertainty is that unless someone's symptoms are typical of gallstones sludge should not be considered the cause of the symptoms.
what is the relationship of sludge to gallstones?