Clinical Importance and Natural History of Biliary Sludge in Outpatients

Improving Diagnosis of Acute Cholecystitis with US: New Paradigms

Acute cholecystitis is an inflammatory condition of the gallbladder typically incited by mechanical obstruction. Accurate diagnosis of this common clinical condition is challenging due to variable imaging appearances as well as overlapping clinical manifestations with biliary colic, acute hepatitis, pancreatitis, and cholangiopathies. In acute cholecystitis, increased dilatation and high intraluminal pressures lead to gallbladder inflammation and may progress to gangrenous changes, focal wall necrosis, and subsequent perforation. In acute calculous cholecystitis, gallstones are the cause of obstruction and are often impacted in the gallbladder neck or cystic duct, leading to gallbladder inflammation. In acalculous cholecystitis, patients are typically critically ill, often with hypotensive episodes and prolonged gallbladder stasis, which lead to obstruction, gallbladder ischemia, and inflammation. Helpful sonographic findings of acute cholecystitis include a dilated gallbladder; increased intraluminal pressures in the gallbladder, resulting in a bulging fundus (tensile fundus sign); intraluminal sludge in the setting of right upper quadrant pain; wall hyperemia, which may be quantified by elevated cystic artery velocities or hepatic artery velocities; mucosal ischemic changes, characterized by loss of mucosal echogenicity; pericholecystic inflammation, characterized by hyperechoic pericholecystic fat; and mucosal discontinuity. Extruded complex fluid next to a wall defect is definitive for gallbladder wall perforation, and further evaluation with CT or MRI allows evaluation of the full extent of perforation and other potential complications. The sonographic Murphy sign, while helpful if positive, is relatively insensitive for accurate diagnosis of acute cholecystitis. Thus, overreliance on the sonographic Murphy sign results in surprisingly low diagnostic accuracy in practice.

Consensus definition of sludge and microlithiasis as a possible cause of pancreatitis

OBJECTIVE

In up to 20% of patients, the aetiology of acute pancreatitis (AP) remains elusive and is thus called idiopathic. On more detailed review these cases can often be explained through biliary disease and are amenable to treatment. Findings range from biliary sludge to microlithiasis but their definitions remain fluid and controversial.

DESIGN

A systematic literature review (1682 reports, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines) analysed definitions of biliary sludge and microlithiasis, followed by an online international expert survey (30 endoscopic ultrasound/hepatobiliary and pancreatic experts; 36 items) which led to definitions of both. These were consented by Delphi voting and clinically evaluated in a retrospective cohort of patients with presumed biliary pancreatitis.

RESULTS

In 13% of original articles and 19.2% of reviews, microlithiasis and biliary sludge were used synonymously. In the survey, 41.7% of experts described the term 'sludge' and 'microlithiasis' as identical findings. As a consequence, three definitions were proposed, agreed on and confirmed by voting to distinctly discriminate between biliary sludge (hyperechoic material without acoustic shadowing) and microlithiasis (echorich calculi of ≤5 mm with acoustic shadowing) as opposed to larger biliary stones, both for location in gallbladder and bile ducts. In an initial attempt to investigate the clinical relevance in a retrospective analysis in 177 confirmed cases in our hospital, there was no difference in severity of AP if caused by sludge, microlithiasis or stones.

CONCLUSION

We propose a consensus definition for the localisation, ultrasound morphology and diameter of biliary sludge and microlithiasis as distinct entities. Interestingly, severity of biliary AP was not dependent on the size of concrements warranting prospective randomised studies which treatment options are adequate to prevent recurrence.

Prevalence of gallbladder sludge and associated abnormalities in cats undergoing abdominal ultrasound

The significance of gallbladder sludge in cats remains largely unknown and has been speculated to be a pathologic finding in cats. The objectives of this retrospective, observational study were to determine the prevalence of gallbladder sludge in the population of cats presenting for abdominal ultrasound; to describe clinical signs, laboratory findings and certain abdominal ultrasound abnormalities; and to compare these findings to cats without gallbladder sludge. One hundred and ninety-two cats were included. Medical records were searched for cats with an abdominal ultrasound performed between October 2014-2015. Signalment, clinical signs, complete blood count, biochemical findings, presence or absence of gallbladder sludge, and hepatobiliary and pancreatic ultrasound findings were recorded. Gallbladder sludge was present in 44% of cats that underwent an abdominal ultrasound. There was no significant difference in age, sex, presenting clinical signs or clinicopathologic variables between the two groups. Gallbladder wall thickening significantly increased the odds of detecting gallbladder sludge (OR-3.7 95% CI 1.4 - 10.0). Gallbladder sludge was not associated with other ultrasonographic abnormalities of the liver, gallbladder, bile duct or pancreas. Gallbladder sludge is common in cats undergoing abdominal ultrasound and appears to be a non-specific finding. The clinical significance of concurrent gallbladder sludge and gallbladder wall thickening present on ultrasound in cats remains to be determined.

Acute Acalculous Cholecystitis in Hospitalized Patients With Hematologic Malignancies and Prognostic Importance of Gallbladder Ultrasound Findings

OBJECTIVES

Patients with hematologic malignancies, especially those with acute disease or those receiving intense chemotherapy, are known to develop acute acalculous cholecystitis (AAC). The aim of this study was to evaluate the diagnostic and prognostic value of the established ultrasound (US) diagnostic criteria for AAC in patients with acute hematologic malignancies who were clinically suspected to have AAC.

METHODS

We retrospectively studied the US findings of the gallbladder in patients with hematologic malignancies and correlated these findings with the duration of clinical symptoms, complications, and gallbladder-specific mortality. The major criteria were a 3.5-mm or thicker wall, pericholecystic fluid, intramural gas, and a sloughed mucosal membrane. The minor criteria were echogenic bile and hydrops (gallbladder distension > 4 cm). Ultrasound findings were considered positive if they included 2 major criteria or 1 major and 2 minor criteria.

RESULTS

Ninety-four (25.5%) of 368 patients with hematologic malignancies had clinical signs of AAC during their acute phase of illness or during intense chemotherapy. Forty-three (45.7%) of these 94 patients had AAC-positive test results based on US criteria. The mean duration of symptoms was significantly longer (7.8 days) in this group than among the patients with negative test results (3.9 days; P < .001). Patients with positive test results had a higher rate of complications or mortality (20.9%) than those with negative test results (0%; P < .001).

CONCLUSIONS

Symptomatic patients who meet the US criteria for the diagnosis of AAC have a poor prognosis. Other patients require a close follow-up US examination within 1 week to detect early progression.

Physical Chemistry of Bile: Detailed Pathogenesis of Cholelithiasis

Despite the overwhelming prevalence of cholelithiasis, many health care professionals are not familiar with the basic pathophysiology of gallstone formation. This article provides an overview of the biochemical pathways related to bile, with a focus on the physical chemistry of bile. We describe the important factors in bile synthesis and secretion that affect the composition of bile and consequently its liquid state. Within this biochemical background lies the foundation for understanding the clinical and sonographic manifestation of cholelithiasis, including the pathophysiology of cholesterol crystallization, gallbladder sludge, and gallstones. There is a brief discussion of the clinical manifestations of inflammatory and obstructive cholestasis and the impact on bile metabolism and subsequently on liver function tests. Despite being the key modality in diagnosing cholelithiasis, ultrasound has a limited role in the characterization of stone composition.