The terms biliary sludge and cholesterol microlithiasis(hereafter referred to as microlithiasis)were originated from different diagnostic techniques and may represent different stages of cholesterol gall-stone disease.Although the pathogenesis of biliary sludge and microlithiasis may be similar,micro-lithiasis could be preceded by biliary sludge,followed by persistent precipitation and aggregation of solid cholesterol crystals,and eventually,gallstone formation.Many clinical conditions are clearly associated with the formation of biliary sludge and microlithiasis,including total parenteral nutrition,rapid weight loss,pregnancy,organ transplantation,administration of certain medications,and a variety of acute and chronic illnesses.Numerous studies have demonstrated complete resolution of biliary sludge in approximately 40％of patients,a cyclic pattern of disappearing and reappearing in about 40％,and progression to gallstones in nearly 20％.Although only a minority of patients with ultrasonographic demonstration of biliary sludge develop gallstones,it is still a matter of controversy whether micro-lithiasis could eventually evolve to cholesterol gallstones.Biliary sludge and microlithiasis are asymp-tomatic in the vast majority of patients;however,they can cause biliary colic,acute cholecystitis,and acute pancreatitis.Biliary sludge and microlithiasis are most often diagnosed ultrasonographically and bile microscopy is considered the gold standard for their diagnosis.Specific measures to prevent the development of biliary sludge are not practical or cost-effective in the general population.Laparoscopic cholecystectomy offers the most definitive therapy on biliary sludge.Endoscopic sphincterotomy or surgical intervention is effective for microlithiasis-induced pancreatitis.Ursodeoxycholic acid can effectively prevent the recurrence of solid cholesterol crystals and significantly reduce the risk of recurrent pancreatitis.

Cholesterol gallstone formation represents a failure of biliary cholesterol homeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed.Lithogenic bile is mainly caused by persistent hepatic hypersecretion of biliary cholesterol and sustained cholesterol-supersaturated bile is an essential prerequisite for the precipitation of solid cholesterol monohydrate crystals and the forma-tion of cholesterol gallstones.The metabolic determinants of the supply of hepatic cholesterol molecules that are recruited for biliary secretion are dependent upon the input-output balance of cholesterol and its catabolism in the liver.The sources of cholesterol for hepatic secretion into bile have been extensively investigated;however,to what extent each cholesterol source contributes to hepatic secretion is still unclear both under normal physiological conditions and in the lithogenic state.Although it has been long known that biliary lithogenicity is initiated by hepatic cholesterol hypersecretion,the genetic mecha-nisms that cause supersaturated bile have not been defined yet.Identification of the Lith genes that determine hepatic cholesterol hypersecretion should provide novel insights into the primary genetic and pathophysiological defects for gallstone formation.In this review article,we focus mainly on the path-ogenesis of the formation of supersaturated bile and gallstones from the viewpoint of genetics and pathophysiology.A better understanding of the molecular genetics and pathophysiology of the formation of cholesterol-supersaturated bile will undoubtedly facilitate the development of novel,effective,and noninvasive therapies for patients with gallstones,which would reduce the morbidity,mortality,and costs of health care associated with gallstones,a very prevalent liver disease worldwide.

Gallstone formation is the result of a complex interaction between genetic and nongenetic factors. We searched and reviewed the available literature to define how the primary prevention of gallstones (cholesterol gallstones in particular) could be applied in general practice. Electronic bibliographical databases were searched. Prospective and retrospective cohort studies and case-controlled studies were analyzed and graded for evidence quality. The epidemiological data confirmed that genetic factors are estimated to account for only approximately 25% of the overall risk of gallstones, while metabolic/environmental factors are at least partially modifiable in stone-free risk groups, and are thus modifiable by primary prevention measures related to diet, lifestyle, and environmental factors (i.e., rapid weight loss, bariatric surgery, somatostatin or analogues therapy, transient gallbladder stasis, and hormone therapy). There is no specific recommendation for the secondary prevention of recurrent gallstones. Family physicians can contribute to preventing gallstones due to their capability to identify and effectively manage several risk factors discussed in this study. Although further studies are needed to better elucidate the involvement of epigenetic factors that may regulate the effect of environment and lifestyle on gene expression in the primary prevention of gallstone formation, preventive interventions are feasible and advisable in the general practice setting.
Bariatric Surgery ; Bile Acids and Salts ; Case-Control Studies ; Cohort Studies ; Diet ; Epigenomics ; Gallbladder ; Gallstones* ; Gene Expression ; General Practice ; Humans ; Life Style ; Mental Competency* ; Obesity ; Physicians, Family* ; Primary Prevention ; Prospective Studies ; Retrospective Studies ; Risk Factors ; Secondary Prevention ; Somatostatin ; Weight Loss

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.