Consensus Definition of Biliary Microlithiasis and Sludge: Results from a systematic review of the literature, expert survey and consensus meeting

Introduction In up to 20% the etiology of acute pancreatitis (AP) remains elusive after routine work-up. Nevertheless, a biliary etiology warrants treatment to prevent recurrence. According to international guidelines EUS is recommended to exclude occult microlithiasis/biliary sludge as cause of pancreatitis. In a systematic literature review we analysed definitions of biliary sludge and microlithasis. In an expert survey we aimed for a consensus definition allowing to prospectively determine the risk of biliary pancreatitis from sludge and/or microlithiasis.

Methods Following the PRISMA guideline and derived from a systematic review of the literature an online-survey (36 questions: clinical cases, definition, treatment strategy) was developed and sent to 30 HBP and EUS experts from 11 countries and 4 continents to coin definitions agreed on by audience voting (EPC 2021).

Results The literature review demonstrated that in 13% of original articles and 19.2% of reviews, microlithiasis and biliary sludge are used as synonyms and in the survey 41.7% experts described the term “biliary sludge” and “biliary microlithiasis” as identical finding, illustrating the clinical dilemma. As result of the survey three definitions were proposed, agreed and confirmed.

1. The term „biliary sludge“ can be used both to diagnose findings in the bile duct as well as the gallbladder.

2. Discrete, hyperechoic material inside the gallbladder or the bile duct, without acoustic shadowing, which sediments in the most dependent part of the gallbladder represents biliary sludge.

3. The term „biliary microlithiasis“ should be used exclusively for cases in which EUS examination of the biliary tree reveals presence of stones bigger than 3 and less than 5 mm (in diameter).

Summary We propose for the first time a definition of the localization, sonomorphology and size of biliary sludge as well as microlithiasis. Its relevance for risk assessment of pancreatitis and treatment recommendation needs testing in prospective studies.

Publication History

Article published online:
29 March 2022