41 yo F without significant PMH, presenting with 1 day of epigastric pain associated with nausea and chills. In the ED, patient was found to have +RUQ tenderness on exam. A bedside ultrasound was performed, revealing…
a 7mm impacted stone near GB neck, in addition to…
a 7.7mm CBD.
+Sonographic murphy’s sign
Below is an example of cholecystitis with GB wall thickening and pericholecystic fluid.
A radiology ultrasound confirmed findings appreciated on POCUS.
The patient underwent therapeutic ERCP and was then taken to the OR the next day for an uncomplicated laparoscopic cholecystectomy.
Transabdominal RUQ US is the initial study of choice for detecting biliary pathology (quick, noninvasive, no radiation risk, cost-effective). Ultrasound has been shown to be superior to CT in identifying acute cholecystitis. The signs of acute cholecystitis on ultrasound include:
- the presence of gallstones and/or sludge
- a thickened anterior gallbladder wall (>3mm),
- pericholecystic fluid, and
- the presence of sonographic Murphy’s sign.
It is important to assess the common bile duct (CBD) during your RUQ exam, as a dilated CBD can indicate an obstructing stone in the duct, which would change management and warrant further evaluation with MRCP or ERCP. A Cochrane meta-analysis of 5 studies found a pooled sensitivity and specificity of 73% and 91%, respectively, for ultrasound detection of choledocholithiasis. As CBD diameters can increase with age, a general rule of thumb for a normal CBD measurement is 4mm + 1mm for every decade after 40. When the CBD is the same size as the portal vein, also known as the “double barrel” or “shot gun” sign, there is cause for alarm. However, patients s/p cholecystectomy can have dilated CBDs at baseline up to 1cm. The American Society for Gastrointestinal Endoscopy has proposed a risk stratification tool to identify those patients with symptomatic cholelithiasis who may be at risk for choledocholithiasis (see Table below), which can be used in conjunction with your RUQ US. Suggested management for each risk category is shown in the associated flow chart.
ASGE Standards of Practice Committee. The role of endoscopy in the evaluation of suspected choledocholithiasis. Journal of Gastrointestinal Endoscopy. 2010;71(1):1.
Gurusamy KS, et al. Ultrasound versus liver function tests for diagnosis of common bile duct stones. Cochrane Database Syst Rev. 2015 Feb 26;(2):CD011548.
Harvey RT, Miller WT Jr. Acute biliary disease: initial CT and follow up US versus initial US and follow up CT. Radiology 1999 Dec; 213(3):831-6.