Article Summary
1. Why is this topic important? Emergency physicians are using more point-of-care biliary ultrasound, but less experienced sonographers often identify the common bile duct (CBD) incorrectly. This raises concern for biliary
Right upper quadrant (RUQ) abdominal pain is common in patients in the emergency department (ED). The goal of ED evaluation is to identify clinically significant biliary pathology, such as cholecystitis and choledocholithiasis, that may merit prompt surgical consultation, operative intervention, or admission. These patients typically undergo serum laboratory testing and most often receive a RUQ ultrasound as the first-line imaging modality. Focused point-of-care (POC) biliary ultrasound has been shown to expedite the care of patients presenting with possible biliary disease and decrease duration of stay in the ED (1). POC biliary ultrasound typically includes sagittal and transverse views of the gallbladder to assess for the presence or absence of gallstones and sonographic evidence of cholecystitis, such as gallbladder wall thickening > 3 mm (GWT), pericholecystitic fluid (PCF), and sonographic Murphy’s sign (SMS). Views of the portal triad are also obtained and the common bile duct (CBD) diameter is measured 2, 3. From our experience teaching emergency physicians, residents, and medical students, it is the proper and timely identification of the CBD that proves most difficult for the novice sonographer.
The typical presentation of cholecystitis includes sonographic cholelithiasis with variable combinations of SMS, GWT, PCF, and abnormalities in serum blood testing 2, 4. CBD diameter is not generally included in the diagnostic criteria for cholecystitis, but there is a paucity of published data looking specifically at the prevalence of CBD dilation in the setting of acute cholecystitis (2). Conversely, CBD dilation has been a traditional diagnostic marker for possible choledocholithiasis; however, the literature suggests that a significant proportion of ductal stones occur without sonographic CBD dilation and a majority of choledocholithiasis cases have concurrent serum laboratory abnormalities 5, 6, 7. We sought to determine what unique information CBD diameter adds to the evaluation for cholecystitis and choledocholithiasis in ED patients.
The aim of this study was to determine the prevalence of isolated sonographic CBD dilation in ED patients with cholecystitis or choledocholithiasis without laboratory abnormalities or other pathologic findings on biliary ultrasound.
This was a retrospective chart review performed at a single academic, tertiary care hospital with Emergency Medicine and Radiology residency programs. The research team comprised two emergency ultrasound fellows, one emergency medicine resident, one medical student, and four undergraduate research assistants.
After approval by the institutional review board, master patient lists were obtained via a medical records query using codes from the International Classification of Diseases, 9th revision
The first cohort included 734 patients undergoing cholecystectomy between June 2000 and July 2010. Patients were 9–90 years of age, and the cohort was 70.8% female. A total of 666 charts were included after 40 (5.4%) exclusions for missing ultrasound or CBD measurements and 28 (3.8%) for missing pathology reports. Of the 666 inclusions, 633 (95.1%) had confirmed cholecystitis according to the final pathology report.
There were 301 (45.2%) unique patient charts that revealed ≥1 equivocal or
Few (<1%) ED patients with cholecystitis requiring cholecystectomy or choledocholithiasis present with isolated sonographic CBD dilation. In the setting of an ultrasound without GWT, PCF, or SMS and normal laboratory testing, our results suggest sonographic CBD measurement has limited use in diagnosing cholecystitis and choledocholithiasis.
Clinical medicine has traditionally eschewed sonographic CBD measurement as a diagnostic marker for acute cholecystitis, and the results of the first cohort
The prevalence of isolated sonographic CBD dilation in cholecystitis and choledocholithiasis is <1%. Omission of CBD measurement is unlikely to result in missed cholecystitis or choledocholithiasis in the setting of a routine ED evaluation with an otherwise normal ultrasound and normal laboratory values. 1. Why is this topic important? Emergency physicians are using more point-of-care biliary ultrasound, but less experienced sonographers often identify the common bile duct (CBD) incorrectly. This raises concern for biliaryArticle Summary
We thank Stacy Hata, Catherine Kelly, Erik Kochert, Michael Menchine, Natalie Nguyen, Andrew Richardson, Amy Stacey, and Maryjane Vennat.
The CBD diameter should measure approximately 4 mm in adult patients 40 years old and under, then 1 mm is added for each decade (i.e., 5 mm by age 50, 6 mm by age 60, etc.). The utility of POCUS for isolated CBD assessment has not been shown to be as good for decision-making as other findings such as gallstones, wall thickening, and pericholecystic fluid are for diagnosing cholecystitis (12). However, there may be utility in evaluating the CBD for normalization of duct diameter among patients who clinically have passed a stone (13).
This proposed guide for pediatric CBD size should be used in conjunction with patient history, exam, additional signs on imaging, and laboratory studies including LFTs and TB. It is likely that, just as in the adult population, the ultimate diagnosis of CDL will depend on multiple factors and not just the CBD size [5,19,20]. It is important to more clearly define the diagnostic criteria for pediatric CBD obstruction in order to better understand the prevalence of the disease and also to determine the best treatment option for the patient.
In the face of uncertain CBD identification, the ability of normal laboratory tests and an otherwise normal RUQ US to exclude complicated biliary pathology would be of great clinical benefit. Prior research has suggested that CBD diameter yields limited unique clinical information in patients with cholecystitis and choledocholithiasis with normal laboratory values; however, there are no prospective studies to date that have confirmed these findings [17-21]. We sought to prospectively assess the importance of sonographic CBD measurement in evaluating patients for biliary pathology, particularly in the setting of normal laboratory values and an otherwise unremarkable biliary US.
The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the US Army, Department of Defense, or the US Government.
Reprints are not available from the authors.