Diagnostic accuracy of ultrasonography in adults with obstructive jaundice

Diagnostic and predictive ability of hyperbilirubinemia severity in cats: A multicenter retrospective study

BACKGROUND

Total serum bilirubin concentration (TBIL) can provide useful information on several pathophysiological conditions in cats. Nevertheless, whether the variable severity classification of hyperbilirubinemia can reliably indicate certain disease processes or predict a biliary obstruction (BO) has not been investigated.

HYPOTHESIS/OBJECTIVE

Determine if hyperbilirubinemia of variable severity can assist clinicians to identify BO, which often is considered a surgical emergency.

ANIMALS

Two-hundred sixteen client-owned cats.

METHODS

Data were retrospectively collected from all cats (January 2015-August 2022) with an increased TBIL (>0.58 mg/dL [>10 μmol/L]) presented to 3 referral centers in the United Kingdom (UK). Presenting clinical features and diagnostic outcomes were collected. The predictive ability of TBIL to indicate BO was evaluated by multivariable binary logistic regression modeling and receiver operating characteristic (ROC) curves.

RESULTS

Median TBIL was 1.73 mg/dL (range, 0.59-26.15; 29.5 μmol/L; range, 10.1-447.1) with severity classification of hyperbilirubinemia categorized as mild (>0.58-2.92 mg/dL; >10-50 μmol/L; 68.1%), moderate (>2.92-5.85 mg/dL; >50-100 μmol/L; 17.6%), severe (>5.85-11.70 mg/dL; >100-200 μmol/L; 9.7%) and very severe (>11.70 mg/dL; >200 μmol/L; 4.6%). Biliary obstruction was present in 17 (7.9%) cats, all of which received recommendation for emergency surgery. Median TBIL in cats with BO (9.69 mg/dL; 165.7 μmol/L) differed significantly from those without obstruction (1.51 mg/dL; 25.8 μmol/L; P < .01). The optimal TBIL cut-off to discriminate between cats with and without BO was ≥3.86 mg/dL (≥66 μmol/L) with a sensitivity of 94.1% and specificity of 82.4%. Using multivariable logistic regression, as age increased, the odds of BO increased significantly (odds ratio, 1.20; 95% confidence interval, 1.01-1.42; P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

As part of a thorough clinical assessment, the severity classification of hyperbilirubinemia has the potential to predict the likelihood of a BO and to discriminate between cats that may or may not require surgery for BO at a suggested cut-off of ≥3.86 mg/dL (≥66 μmol/L). Alongside TBIL, age is also useful when assessing for the likelihood of BO in a cat presented with hyperbilirubinemia.

Accuracy of Ultrasound Imaging for Etiology of New-Onset Painless Jaundice

PURPOSE

Ultrasound (US) is considered a first-line study for painless jaundice. However, in our hospital system, patients with new-onset painless jaundice often have a contrast-enhanced computed tomography (CECT) or magnetic resonance cholangiopancreatography (MRCP) regardless of the sonographic findings. Thus, we investigated the accuracy of US for detection of biliary dilatation in patients with new-onset painless jaundice.

METHODS

Our electronic medical record was searched from January 1, 2012, to January 1, 2020, for adult patients with new-onset painless jaundice. Presenting complaint/setting, laboratory values, imaging studies/findings, and final diagnoses were recorded. Patients with pain or known liver disease were excluded. A gastrointestinal physician reviewed the laboratory values/chart to classify the type of suspected obstruction. Two radiologists blindly re-reviewed the US scans, and κ between the radiologists was calculated. Fisher exact test and the 2-sample t test were used for statistical analysis.

RESULTS

Three hundred sixty patients presented with jaundice (>3 mg/dL), of whom 68 met the inclusion criteria (no pain and no known liver disease). Laboratory values had an overall accuracy of 54%, but were accurate in 87.5% and 85% for obstructing stones/pancreaticobiliary cancer. Ultrasound demonstrated overall accuracy of 78%, but only 69% for pancreaticobiliary cancer and 12.5% for common bile duct stone. Seventy-five percent of the patients underwent follow-up CECT or MRCP regardless of presenting setting. In the emergency department or inpatient setting, 92% of the patients underwent CECT or MRCP regardless of US, and 81% had follow-up CECT or MRCP within 24 hours.

CONCLUSION

A US-first strategy in the setting of new-onset painless jaundice is accurate only 78% of the time. In practice, US was almost never a stand-alone imaging examination in patients presenting to the emergency department or inpatient setting with new-onset painless jaundice, no matter the suspected diagnosis based on clinical and laboratory grounds or on the US findings themselves. However, for milder elevations of unconjugated bilirubin (suspicious for Gilbert disease) in the outpatient setting, a US demonstrating lack of biliary dilatation was often a definitive study for exclusion of pathology.

Diagnosis of Cholangiocarcinoma

Cholangiocarcinoma (CCA), a tumor of the bile duct epithelium, is increasing in incidence. CCA remains a highly fatal malignancy because early diagnosis is difficult. Based on its anatomical location, CCA can be categorized into the following three groups: perihilar, intrahepatic, and extrahepatic. Patients with CCA complain of asymptomatic jaundice, weight loss, and right upper quadrant abdominal discomfort. Imaging modalities, including transabdominal ultrasound, computed tomography, and magnetic resonance imaging, play an important role in detecting tumors as well as guiding biopsy procedures and staging workups in CCA. Characteristically, extrahepatic CCA shows abrupt changes in ductal diameter with upstream ductal dilation. Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) are recommended as the next step in the evaluation of extrahepatic CCA. Tissue is obtained through EUS-FNA or ERCP (biopsy, brush cytology), and therapeutic intervention (such as stent insertion) is performed with ERCP. Moreover, several serum tumor markers (carbohydrate antigen 19-9 and carcinoembryonic antigen) can be useful in diagnosing CCA in some patients.

Ultrasonographic evaluation of patients with abnormal liver function tests in the emergency department

Ultrasonography is often the initial modality used to evaluate patients found to have abnormal liver function tests (LFTs) in the emergency department. While an assessment for biliary ductal dilatation and obstruction remains one of the main questions to answer, radiologists should also be aware of the ultrasonographic appearance of other conditions that can cause abnormal LFTs. This may be crucial for the management and disposition of patients in the emergency department. This article reviews the ultrasonographic features of diseases that may cause abnormal LFTs.