Tag: gallbladder

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Case 75: Detection of Choledocholithiasis Using Point-of-Care Ultrasound with Limited Visualization of the Common Bile Duct

Maya Ibelaidene, Rachna Subramony

A 45 year old male with a past medical history of gastric sleeve presented to the Emergency Department with two days of progressively worsening right upper quadrant (RUQ) abdominal pain. The pain was constant, dull in character, and radiated intermittently to the back. It was associated with nausea, vomiting, fever, chills, but no chest pain, or changes in bowel habits. He denied prior similar episodes, alcohol misuse, or known gallstone disease. There was no history of liver disease.

Vital Signs: BP 130/83 mmHg | HR 56 | T 98.7°F | RR 18 | SpO₂ 100% on room air

The patient appeared uncomfortable but was not in acute distress. Cardiopulmonary examination was unremarkable. Abdominal examination revealed focal tenderness in the RUQ with a positive Murphy’s sign. There was no rebound, guarding, or palpable mass. No scleral icterus was noted.

Laboratory studies demonstrated elevated liver enzymes with a cholestatic pattern: AST 186 U/L, ALT 501 U/L, alkaline phosphatase 512 U/L, and total bilirubin 6.2 mg/dL (direct predominance).

Given the patient’s RUQ pain and abnormal liver function tests, a point of care ultrasound (POCUS) of the RUQ was performed at the bedside to evaluate for biliary pathology. Examination was conducted using a low-frequency (2–5 MHz) curvilinear transducer. The gallbladder was assessed in longitudinal and transverse planes.

Figure 1: Markedly distended gallbladder with gallstones and posterior acoustic shadowing. Source: Radiopaedia

The gallbladder appeared significantly enlarged, consistent with biliary obstruction. Multiple echogenic foci with posterior acoustic shadowing were noted within the lumen.

Despite careful scanning, the common bile duct (CBD) was difficult to visualize clearly at the bedside. Attempts were made in multiple planes and patient positions; however, bowel gas and patient body habitus limited optimal delineation of the duct. No obvious intrahepatic biliary ductal dilation was confidently identified on POCUS.

Given laboratory evidence of cholestasis and a distended gallbladder concerning for distal obstruction, formal radiology performed ultrasound was obtained, demonstrating dilation of the CBD measuring 9 mm with an obstructing distal stone consistent with choledocholithiasis.

Subsequent magnetic resonance cholangiopancreatography (MRCP) confirmed the presence of a CBD stone. The patient underwent endoscopic retrograde cholangiopancreatography (ERCP) with successful stone extraction and clinical improvement.

Discussion

Choledocholithiasis, defined as the presence of gallstones within the CBD, commonly presents with right upper quadrant pain, jaundice, and cholestatic liver enzyme abnormalities, and may progress to acute cholangitis or gallstone pancreatitis if untreated. POCUS is highly sensitive for detecting cholelithiasis and sonographic features of acute cholecystitis, but direct visualization of the CBD can be technically challenging in the emergency setting.

Bedside ultrasound reliably detects gallstones, gallbladder wall thickening, pericholecystic fluid, and a sonographic Murphy’s sign. In contrast, evaluation of the CBD requires deliberate technique and careful anatomic identification.

The duct is best located by first identifying the portal triad within the hepatoduodenal ligament. In a transverse view at the porta hepatis, the portal vein appears as the largest circular structure with echogenic walls. The CBD is typically positioned anterolateral to the portal vein, while the hepatic artery lies anteromedial forming the classic “Mickey Mouse sign,” which helps distinguish the CBD from adjacent vascular structures (Figure 2).

Figure 2: Example of “mickey mouse sign” on POCUS. Source: POCUS101

Color Doppler should be used to confirm that the suspected structure is nonvascular, as the CBD should not demonstrate internal flow (Figure 3). Optimal probe placement in the right upper quadrant along the midclavicular line with slight cephalad angulation, combined with rotation between longitudinal and transverse planes, improves visualization. Sliding medially toward the epigastrium and employing deep inspiration or left lateral decubitus positioning may further enhance acoustic windows. When visualized, the CBD should be measured inner wall to inner wall in the transverse plane, with diameters greater than 6 mm generally considered dilated in adults, though this threshold increases with age and prior cholecystectomy. Tracing the duct distally toward the pancreatic head may reveal obstruction, although distal visualization is frequently limited by bowel gas.

Figure 3: Identifying the CBD using color doppler. Source: Taming the SRU

Despite optimization strategies, POCUS has inherent limitations. Bowel gas, body habitus, and operator experience significantly affect image quality, and CBD stones are often not directly visualized. Instead, obstruction may be inferred through indirect findings such as intrahepatic biliary dilation or a markedly distended gallbladder. A case report by Herbst demonstrated POCUS identification of a dilated CBD in a patient with suspected choledocholithiasis, which subsequently normalized on repeat imaging after presumed spontaneous stone passage, underscoring both the dynamic nature of biliary obstruction and the value of serial assessment.¹ Systematic evaluations indicate that while ultrasound reliably identifies CBD dilation, its sensitivity for detecting CBD stones is significantly lower, which necessitates adjunctive imaging for definitive diagnosis.² More recent evidence supports integrating POCUS findings with clinical and laboratory data to improve diagnostic accuracy and expedite management in suspected choledocholithiasis.³

Given these limitations and evidence, confirmatory imaging such as comprehensive abdominal ultrasound, MRCP or ERCP is often required for definitive diagnosis and therapeutic planning.

In this case, the markedly enlarged gallbladder combined with cholestatic laboratory abnormalities heightened suspicion for distal biliary obstruction. Although the CBD was not clearly visualized on POCUS even with such a dilated gallbladder and later formal imaging revealing dilated CBD, the recognition of indirect sonographic findings appropriately prompted further imaging and facilitated timely intervention.

Conclusion

This case highlights both the utility and limitations of POCUS in the evaluation of suspected choledocholithiasis. While POCUS excels in the rapid identification of cholelithiasis and secondary signs of biliary obstruction, direct visualization of CBD stones remains challenging and operator dependent. Recognition of indirect findings such as gallbladder distention, intrahepatic ductal dilation, and supportive laboratory abnormalities plays a critical role in raising suspicion for distal obstruction.

Current literature supports the integration of serial POCUS examinations with clinical assessment and laboratory data to enhance diagnostic accuracy and guide timely management. However, due to its limited sensitivity for detecting CBD stones directly, confirmatory imaging with formal ultrasound, MRCP, or ERCP is often required.

Ultimately, this case underscores the importance of a multimodal diagnostic approach. When used thoughtfully, POCUS serves as a valuable first line tool that can expedite recognition of biliary obstruction, prompt appropriate additional imaging, and facilitate timely intervention, thereby improving patient outcomes in the emergency setting.

References

  1. Herbst et al. Point-of-care ultrasound identification of transient common bile duct dilation due to choledocholithiasis. J Emerg Med. 2021. PMID: 33339646.
  2. Meta-analysis assessing the diagnostic performance of ultrasound for CBD stones and dilation. Clin Imaging. 2014. PMID: 24126067.
  3. Recent evaluation of POCUS utility in suspected choledocholithiasis and clinical decision support. Ultrasound Med Biol. 2022. PMID: 34995366.
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Case 32: Perforated Gallbladder

 

A 77-year old man presented to the emergency department with a complaint of appetite loss over the past 15 days. He reported ongoing symptoms for the past 5 months. However, over the previous 15 days, his appetite had been so poor that he only drank 1-2 nutrition drinks per day. He reported a 10-15 lbs weight loss paired with fatigue and weakness. He denied nausea, vomiting, abdominal pain, fevers, and chills. The patient reported normal bowel movements. He denied any significant medical history and had no records in our EMR. He reported an unremarkable colonoscopy 7-8 years ago.

 

Upon physical examination, he was non-toxic in appearance. Vitals were as follows: 

 

BP: 155/89 | HR: 105 | RR: 16 | T: 99.8 F | Sp02 100% on RA | 

 

The patient had no masses, no hepatomegaly, no flank pain, and no tenderness to the abdomen upon palpation. Laboratory evaluation included a CBC which was remarkable for an elevated white blood count of 23,200 with a left shift. The chemistry panel was notable for normal ALT, AST, bilirubin, and creatinine. 

 

WBC

23.2

(Ref range: 4.0 - 10.0 1000/mm^3)

ANC- Manual mode

20.4

(Ref range: 1.6 - 7.0 1000/mm^3)

Absolute monocytes

1.4

(Ref range: 0.2 - 0.8 1000/mm^3)

ALT

35

(Ref range: 0-41 U/L)

AST

43

(Ref range: 0-40 U/L)

Bilirubin

0.4

(Ref range: <1.2 mg/dL)

Creatinine

0.80

(Ref range: 0.67-1.17 mg/dL)

Bedside ultrasound was performed, and the following images were obtained. In examining these images, what do you notice and how would this change your patient management?

 

Figure 1: Thickened gallbladder wall and echoic sludge surrounding a large gallstone. Gallbladder wall perforations can be seen at 2 o’clock and 11 o’clock.

Figure 2: Increased color flow indicative of inflammation.

 

 

Answer and Learning Points

Figure 3: Thickened gallbladder wall and echoic sludge around the cholelithiasis. Gallbladder wall perforation can be visualized at the 2 o’clock position.

Figure 3: Thickened gallbladder wall and echoic sludge around the cholelithiasis. Gallbladder wall perforation can be visualized at the 2 o’clock position.

Figure 4: Gallbladder wall perforation visualized at the 11 o’clock position.

Figure 4: Gallbladder wall perforation visualized at the 11 o’clock position.

Figure 5: CT image demonstrating gallbladder wall perforation at the 2 o’clock position as well as pericholecystic fluid.

Figure 5: CT image demonstrating gallbladder wall perforation at the 2 o’clock position as well as pericholecystic fluid.

In the images above, a thickened gallbladder wall with “hole-signs” can be seen, indicating perforation.

 

Discussion 

 

Biliary pathology is the third most common cause of acute abdominal pain presenting to the ED [1]. Unfortunately, labs and clinical exam findings, either alone or in combination, are insufficient to reliably rule out biliary pathology [2]. Point-of-care ultrasound (POCUS) in the ED can detect cholelithiasis with a sensitivity and specificity of 89.8% and 88.0%, respectively [3]. Regarding the detection of cholecystitis, ED POCUS features a sensitivity and specificity of  87% and 82%, respectively [4]. In this case, we visualized a perforation and abscess outside the inflamed wall of the gallbladder, illustrating the accuracy and utility of POCUS as a diagnostic tool. 

How to best visualize the gallbladder: 

1. Subcostal sweep: With the marker dot to the patient’s head, place the probe in the subxiphoid/epigastric area. Next, slide the probe slowly to the patient’s right flank until the gallbladder is visualized or one has determined that another view is necessary.

2. Subcostal fanning: With the marker dot to the patient’s right, place the probe in the RUQ abdomen, where one would palpate for a non-ultrasound Murphy’s sign. Fan cephalad to look for the gallbladder in the area under the anterior ribs. 

3. X-7: Start subxiphoid and move the probe approximately 7 cm to the patient’s right, scan in transverse orientation transverse below or through the ribs. If scanning through the ribs, one may need to rotate the probe slightly clockwise to align the probe with the intercostal space.

4. Mid-axillary longitudinal view:  Obtain a view of Morrison's pouch as you would when completing a FAST (marker dot toward the patient’s head, patient supine, and probe placed in the mid axillary line). Remember, the kidney is retroperitoneal. After identifying the hepatorenal interface, slowly fan anteriorly until the gallbladder is directly under the probe. The common bile duct will be parallel and superficial to the portal vein. The inferior vena cava, with its characteristic respiratory variation, will be deep to the portal vein. Use color flow to differentiate the structures, as the common bile duct will not have color flow.

5. Roll the patient: If the above does not yield satisfactory views, roll the patient into a left lateral decubitus position. This will bring the gallbladder to a more anterior location and likely improve visualization of the GB when the steps above are repeated in this new patient position.

Normal Findings:

The upper limit of normal for the adult common bile duct is 6mm up to the age of 60. After this, the upper limit of normal rises an additional 1mm for every decade of life after 60 (e.g. 7mm at 70 years of age). Remember, there is a band of connective tissue called the main lobar fissure (MLF) that anchors both the portal triad and the neck of the gallbladder. Therefore, if you see the portal triad, you can then find the main lobar fissure emanating from the portal triad and track it to the neck of the gallbladder. The converse is true when locating the portal triad after identifying the gallbladder (follow the gallbladder neck, then trace the MLF to the portal triad).

During the examination, measure the thickness of the anterior gallbladder wall. The posterior wall is subject to posterior acoustic enhancement, which may yield an inaccurate measurement. A normal gallbladder wall thickness should measure less than 3 millimeters (mm). This measurement serves as a baseline for evaluating potential abnormalities.

Signs of Cholecystitis: 

Cholecystitis can be diagnosed by observing gallbladder wall thickening greater than 3mm, pericholecystic fluid collection, gallbladder distension, and the presence of a sonographic Murphy's sign (positive when the point of maximal tenderness is identified by pressing the abdomen with the ultrasound probe while the gallbladder is centered on the screen) [5].

The presence of gallstones within the gallbladder lumen can be detected through ultrasound. Gallstones are typically visualized as rounded structures with an bright, anterior outer layer and associated acoustic shadowing (similar to bone). When the stones occupy most of the lumen of the gallbladder, or a gallbladder is contracted around one or more stones, one may appreciate a “Wall Echo Sign”, where the shadowing from the stones obstructs visualization of the posterior wall of the gallbladder. Note that non-calcified stones will not produce shadowing artifacts behind them.

The significance of sludge in ultrasound imaging of the gallbladder can vary depending on the clinical context. Sludge itself can be a precursor to the formation of gallstones. It may indicate an imbalance in the components of bile, such as excess cholesterol or insufficient bile salts, which can lead to the development of gallstones over time. Perforation can be diagnosed by observing gallbladder wall discontinuity or disruption, pericholecystic fluid collection or abscess formation, and signs of free fluid in the abdominal cavity [6].

POCUS is a powerful diagnostic modality for identifying biliary pathology, including cholecystitis, cholelithiasis, and perforation of the gallbladder wall. By following the scanning technique outlined above and identifying findings consistent with biliary pathology, clinicians can obtain accurate diagnoses and facilitate appropriate patient management. POCUS is a valuable tool to use in conjunction with a patient's clinical history, physical examination, and other diagnostic modalities to ensure comprehensive assessment and optimal healthcare outcomes.

 

References

1) Cervellin, Gianfranco, Riccardo Mora, Andrea Ticinesi, Tiziana Meschi, Ivan Comelli, Fausto Catena, and Giuseppe Lippi. 2016. “Epidemiology and Outcomes of Acute Abdominal Pain in a Large Urban Emergency Department: Retrospective Analysis of 5,340 Cases.” Annals of Translational Medicine 4 (19): 362.

2) Trowbridge, Robert L., Nicole K. Rutkowski, and Kaveh G. Shojania. 2003. “Does This Patient Have Acute Cholecystitis?” JAMA: The Journal of the American Medical Association 289 (1): 80–86.

3) Ross, Marshall, Michael Brown, Kyle McLaughlin, Paul Atkinson, Jenny Thompson, Susan Powelson, Steve Clark, and Eddy Lang. 2011. “Emergency Physician-Performed Ultrasound to Diagnose Cholelithiasis: A Systematic Review.” Academic Emergency Medicine: Official Journal of the Society for Academic Emergency Medicine 18 (3): 227–35.

4) Summers, Shane M., William Scruggs, Michael D. Menchine, Shadi Lahham, Craig Anderson, Omar Amr, Shahram Lotfipour, Seric S. Cusick, and J. Christian Fox. 2010. “A Prospective Evaluation of Emergency Department Bedside Ultrasonography for the Detection of Acute Cholecystitis.” Annals of Emergency Medicine 56 (2): 114–22.

5) Simeone, J. F., J. A. Brink, P. R. Mueller, C. Compton, P. F. Hahn, S. Saini, S. G. Silverman, G. Tung, and J. T. Ferrucci. 1989. “The Sonographic Diagnosis of Acute Gangrenous Cholecystitis: Importance of the Murphy Sign.” AJR. American Journal of Roentgenology 152 (2): 289–90.

6) Sood BP, Kalra N, Gupta S, et al. Role of sonography in the diagnosis of gallbladder perforation. J Clin Ultrasound. 2002;30(5):270-274. doi:10.1002/jcu.10071

This post was written by Cameron Olandt, Ben Supat, MD, MPH, and Colleen Campbell, MD. Posted by Ben Supat, MD, MPH.

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