Gallstones.
Gallstone prevalence is correlated with geographical and ethnic variations. It is more prevalent in Western communities. There are evidences for a high prevalence in Saudi Arabia. According to their chemical constitutes, stones are classified into cholesterol, mixed and pigment stones. Three main factors, saturation, gallbladder function and nucleation defect are implemented in the pathogenesis of stone formation. Majority of gallstones patients are asymptomatic. Dyspeptic symptoms are not specific. Ultrasonography has become the method of choice for screening and diagnosis of gallstones. Cholecystoscintigraphy is accurate in the diagnosis of acute cholecystitis, biliary obstruction and bile leak. Treatment of gallstones will be discussed in the following issue.