From the Guidelines
For potential jaundice causes, a comprehensive abdominal ultrasound with specific focus on the hepatobiliary system should be ordered. This should include evaluation of the liver parenchyma, gallbladder, bile ducts (both intrahepatic and extrahepatic), pancreas, and portal venous system. Request that the radiologist specifically measure the common bile duct diameter and evaluate for any biliary dilation, stones, masses, or obstruction. The ultrasound should be performed after the patient has fasted for at least 6 hours to optimize gallbladder visualization. This imaging modality is the appropriate first-line choice because it's non-invasive, doesn't use radiation, and can effectively differentiate between obstructive causes (like gallstones, bile duct strictures, or pancreatic masses) and non-obstructive causes (such as hepatitis or cirrhosis) of jaundice. Ultrasound can detect biliary dilation with approximately 90% sensitivity when obstruction is present, as supported by studies such as 1. If the ultrasound findings are inconclusive or suggest obstruction, further imaging such as MRCP (Magnetic Resonance Cholangiopancreatography) or CT may be necessary as follow-up studies.
Key Components of the Ultrasound
- Evaluation of the liver parenchyma
- Gallbladder assessment
- Bile ducts (intrahepatic and extrahepatic) evaluation
- Pancreas assessment
- Portal venous system evaluation
- Measurement of the common bile duct diameter
- Evaluation for biliary dilation, stones, masses, or obstruction
Rationale for Ultrasound as the First-Line Choice
- Non-invasive
- No radiation
- Effective differentiation between obstructive and non-obstructive causes of jaundice
- High sensitivity for detecting biliary dilation when obstruction is present, as noted in 1 and 1
- Recommendation by organizations such as the American College of Gastroenterology, as mentioned in 1 and 1
Additional Considerations
- The patient should fast for at least 6 hours before the ultrasound to optimize gallbladder visualization.
- If the ultrasound findings are inconclusive or suggest obstruction, further imaging may be necessary.
- The choice of further imaging (MRCP or CT) depends on the specific clinical scenario and the availability of resources, as discussed in 1 and 1.
From the Research
Abdominal Ultrasound for Investigating Jaundice
To investigate the cause of potential jaundice (hyperbilirubinemia), the following abdominal ultrasound should be ordered:
- Ultrasonography of the abdomen 2, 3, 4 This is considered a first-line option for patients presenting with jaundice, depending on the suspected underlying etiology.
Key Points to Consider
- The evaluation of jaundice should start with a careful history and physical examination, followed by directed imaging of the biliary tree and liver 2, 5
- Laboratory evaluation should include assays for bilirubin (total and fractionated), aspartate transaminase, alanine transaminase, gamma-glutamyltransferase, alkaline phosphatase, albumin, prothrombin time, and international normalized ratio 2
- Measuring fractionated bilirubin allows for determination of whether the hyperbilirubinemia is conjugated or unconjugated 2
- Ultrasound scan of the liver can clarify whether a liver disease or a biliary tract obstruction is present, and whether the patient should be referred to an internist or a surgeon 3
Imaging Modalities
- Ultrasonography of the abdomen is a first-line option for patients presenting with jaundice 2, 3, 4
- Computed tomography with intravenous contrast media and magnetic resonance cholangiopancreatography are also first-line options, depending on the suspected underlying etiology 2
- A US-first strategy in the setting of new-onset painless jaundice is accurate only 78% of the time 4