BACKGROUND: The process of microcrystallization, its sequel and the assessment of nucleation time is ignored. This systematic review aimed to highlight the importance of biliary microlithiasis, sludge, and crystals, and their association with gallstones, unexplained biliary pain, idiopathic pancreatitis, and sphincter of Oddi dysfunction.
DATA SOURCES: Three reviewers performed a literature search of the PubMed database. Key words used were "biliary microlithiasis", "biliary sludge", "bile crystals", "cholesterol crystallisation", "bile microscopy", "microcrystal formation of bile", "cholesterol monohydrate crystals", "nucleation time of cholesterol", "gallstone formation", "sphincter of Oddi dysfunction" and "idiopathic pancreatitis". Additional articles were sourced from references within the studies from the PubMed search.
RESULTS: We found that biliary microcrystals account for almost all patients with gallstone disease, 7% to 79% with idiopathic pancreatitis, 83% with unexplained biliary pain, and 25% to 60% with altered biliary and pancreatic sphincter function. Overall, the detection of biliary microcrystals in gallstone disease has a sensitivity ranging from 55% to 87% and a specificity of 100%. In idiopathic pancreatitis, the presence of microcrystals ranges from 47% to 90%. A nucleation time less than 10 days in hepatic bile or ultra-filtered gallbladder bile has a specificity of 100% for cholesterol gallstone disease.
CONCLUSIONS: Biliary crystals are associated with gallstone disease, idiopathic pancreatitis, sphincter of Oddi dysfunction, unexplained biliary pain, and post-cholecystectomy biliary pain. Pathways of cholesterol super-saturation, crystallisation, and gallstone formation have been described with scientific support. Bile microscopy is a useful method to detect microcrystals and the assessment of nucleation time is a good method of predicting the risk of cholesterol crystallisation.