Supersaturation of cholesterol in bile is a necessary condition, but not a sole cause, of cholesterol gallstone formation because supersaturation is frequent in the bile of fasting persons without gallstones. The other critical factor in determining whether gallstones form is regulation of the initiating process, cholesterol monohydrate crystal formation. The dynamic interplay of forces for and against cholesterol crystal nucleation and growth in the gallbladder includes the actions of specific proteins or apoproteins, gallbladder mucin, and gallbladder stasis. Virtually all gallstones form within the gallbladder, but stones may form in the bile duct after cholecystectomy or behind strictures as a result of stasis. The clinical consequences of stone formation in the gallbladder are exceedingly variable.
Most patients remain asymptomatic for long periods, frequently for life.
Stones may traverse the cystic duct with or without symptoms of obstruction. Transient cystic duct obstruction results in colicky pain, whereas persistent obstruction usually produces inflammation and acute cholecystitis. In contrast to other types of colic, biliary colic typically is constant, with pain progressively rising to a plateau and falling gradually, lasting up to several hours. Nausea and vomiting are often associated. Fever and chills are absent in uncomplicated gallbladder colic.