Best Next Step in Evaluation

Liver ultrasound (US) is the best next step in evaluating this obese female patient with 9 months of jaundice and pruritus. 1

Rationale for Ultrasound as Initial Imaging

Ultrasound is the first-line imaging modality recommended by both the American College of Radiology and the European Association for the Study of the Liver for differentiating intrahepatic from extrahepatic cholestasis in patients presenting with jaundice. 1
The 9-month duration of symptoms suggests chronic cholestatic disease rather than acute obstruction, making systematic evaluation starting with US appropriate. 1
US has high specificity (71%-97%) for detecting biliary obstruction and can confirm or exclude mechanical causes of jaundice. 1
US can identify features of chronic liver disease such as cirrhosis (sensitivity 65%-95%, positive predictive value 98%), which is critical in a patient with prolonged symptoms. 1, 2

The US findings will guide subsequent management along two distinct pathways:

MRCP becomes the next appropriate step to identify the cause and level of obstruction, particularly valuable in obese patients where US visualization may be limited by body habitus. 1, 3
MRCP has sensitivity of 85-100% and specificity of 90% for biliary obstruction and is non-invasive compared to ERCP. 3
ERCP should be reserved for cases where therapeutic intervention is anticipated, given its 4-5% morbidity and 0.4% mortality risk. 1

Consider medical, metabolic, or functional etiologies such as primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), or drug-induced cholestasis. 1
The combination of jaundice and pruritus in a female patient raises particular concern for PBC, which requires testing for antimitochondrial antibodies (AMA). 1
If US is negative and clinical workup remains inconclusive, MRCP may still be valuable to evaluate for primary sclerosing cholangitis or early biliary cirrhosis before proceeding to liver biopsy. 1
Liver biopsy should be considered in patients with unexplained intrahepatic cholestasis and negative AMA testing after imaging excludes obstruction. 1

While CT has good sensitivity (74%-96%) and specificity (90%-94%) for biliary obstruction, it is not the recommended first-line test. 1
CT exposes the patient to radiation and is less cost-effective than US for initial evaluation. 1
CT is more appropriate after US when malignancy staging is needed or when US findings are inconclusive. 1

MRCP is premature without first performing US to establish whether biliary dilatation exists. 1, 3
MRCP is the appropriate next step after US demonstrates biliary dilatation or when US is negative but clinical suspicion for PSC or PBC remains high. 1, 3
Proceeding directly to MRCP bypasses the cost-effective initial screening that US provides. 1

Liver biopsy is indicated only after imaging (starting with US) has been performed and medical causes are being considered. 1
The American College of Gastroenterology recommends liver biopsy after negative US and inconclusive laboratory workup for intrahepatic cholestasis. 1
Performing biopsy before imaging risks missing treatable obstructive causes and may yield false-negative results in early disease. 1

Do not skip US and proceed directly to advanced imaging (MRCP or CT), as this violates established diagnostic algorithms and is not cost-effective. 1
Obesity may limit US visualization, but this does not justify bypassing US entirely; rather, it means MRCP may be needed sooner if US is technically limited. 3
Do not assume non-obstructive disease without imaging confirmation, as chronic partial obstruction can present with prolonged symptoms. 1
In female patients with chronic cholestasis and pruritus, always consider PBC and check AMA levels alongside imaging. 1