Value of serum alkaline phosphatase, aminotransferases, gamma-glutamyl transferase, leucine aminopeptidase, and bilirubin in the distinction between benign and malignant diseases causing jaundice and cholestasis: results from a prospective study

Malignant biliary strictures in patients with a normal bilirubin and/or normal liver enzymes

BACKGROUND

To date, no studies have sought to determine the frequency of malignancy in patients presenting with a putative biliary stricture and normal liver function tests (LFTs). The primary aim of this retrospective cohort study was to determine the likelihood of malignancy in patients presenting with a biliary stricture and normal LFTs, a normal bilirubin level either alone or in combination with normal levels of liver enzymes [alkaline phosphatase (ALP) and alanine transaminase (ALT)]. A secondary aim was to determine any clinical/biochemical/sonographic features that may be associated with malignancy.

METHODS

Patients presenting over a 10-year period were included. Fifteen variables were analysed to determine their association with malignant disease.

RESULTS

Eight hundred and thirty patients with putative biliary strictures were included. Primary hepatopancreaticobiliary (HPB) cancers presented with a normal bilirubin and normal liver enzymes (ALP and ALT) in 6% of cases. Patients with a putative biliary stricture and a normal bilirubin level whose final diagnoses were pancreatic cancer, ampullary cancer, distal cholangiocarcinoma and hilar cholangiocarcinoma represented 21%, 13%, 7% and 9% of individuals diagnosed with these pathologies, respectively. Hypoalbuminaemia and isolated intrahepatic duct dilatation on ultrasound were significantly associated with malignancy in patients with normal bilirubin and completely normal LFTs.

CONCLUSIONS

This study has shown that patients with a putative biliary stricture and completely normal LFTs are unlikely to have a primary HPB malignancy. Those presenting with a normal bilirubin level, but deranged liver enzymes (ALP and/or ALT), are more likely to have malignant disease, and this should necessitate a higher degree of clinical suspicion.

Etiology of new-onset jaundice: how often is it caused by idiosyncratic drug-induced liver injury in the United States?

BACKGROUND AND AIM

The epidemiology of acute drug-induced liver injury (DILI) in the United States has not been well studied. We conducted a study of adults with new-onset jaundice at a nonreferral community hospital to better understand the epidemiology of acute DILI.

METHODS

This is a retrospective study of adult outpatients and inpatients (> or =18 yr) with new-onset jaundice over a 5-yr period (1999-2003) at Wishard Memorial Hospital, Indiana. Patients with new-onset jaundice were identified using our electronic medical record system and individual medical records were reviewed to extract the required clinical data. New-onset jaundice was defined as the presence of total serum bilirubin >3 mg/dL in patients without a prior total bilirubin >3 mg/dL.

RESULTS

A total of 732 eligible adults constituted our study cohort. Sepsis or altered hemodynamic state resulting in presumed ischemic liver injury is the single most common cause of jaundice (22%). Acute liver disease as a result of nonalcoholic etiologies caused new-onset jaundice in 97 patients (13%), with acute viral hepatitis in 66 patients (9%) and DILI in 29 patients (4%). Most cases of DILI were as a result of acetaminophen toxicity with idiosyncratic DILI occurring in only five patients (0.7%). No mortality was observed at 6 wk in patients who developed idiosyncratic DILI.

CONCLUSION

Idiosyncratic DILI appears to be a rare cause of new-onset jaundice in a community hospital setting.

Differentiation between benign and malignant hilar obstructions using laboratory and radiological investigations: a prospective study

BACKGROUND

Preoperative determination of the aetiology of bile duct strictures at the hilum is difficult. We evaluated the diagnostic accuracy of laboratory parameters and imaging modalities in differentiating between benign and malignant causes of hilar biliary obstruction.

PATIENTS AND METHODS

Fifty-eight patients (26 men) with a history of obstructive jaundice and liver function tests (LFTs) and ultrasound suggestive of biliary obstruction at the hilum were studied. They were evaluated by tumour marker assay (CA19-9), CT and MRI/MRCP. A single experienced radiologist, blinded to the results of other tests, evaluated the imaging. The final diagnosis was made either from histology of the resected specimen, operative findings or image-guided biopsy in inoperable patients. A receiver operator characteristic (ROC) curve was constructed for each laboratory parameter to determine optimal diagnostic cut-off to predict malignant biliary stricture (MBS).

RESULTS

In all, 34 patients had a benign and 24 had malignant aetiology. The mean age of benign patients was 38 years compared with 54 years for MBS. Forty-seven patients were treated with surgery while 11 had ERCP/PTC and stenting. The ROC curve showed that preoperative bilirubin level >8.4 mg/dl (sensitivity 83.3%, specificity 70%), alkaline phosphatase level >478 IU (sensitivity 63%, specificity 49%) and CA19-9 levels >100 U/L (sensitivity 45.8%, specificity 88.2%) for predicting MBS. The sensitivity, specificity and diagnostic accuracy of MRI/MRCP (87.5%, 85.3%, 82.7%, respectively) was marginally superior to CT (79.2%, 79.4%, 79.3%, respectively).

CONCLUSIONS

Patients with a bilirubin level of >8.4 mg% and CA19-9 level >100 U/L were more likely to have malignant aetiology. MRI/MRCP was a better imaging modality than CT.

Serum enzymes associated with cholestasis

Alkaline phosphatase, gamma-glutamyl transferase, and 5' nucleotidase are the most common enzymes used in the evaluation of cholestasis. The present knowledge of these enzymes including their function, activity measurement, biologic variables of enzyme activity in healthy persons and disease states, and clinical significance are reviewed. Usefulness of enzymes patterns for diagnosis of specific cholestatic disorders and future directions in evaluation of cholestasis are also discussed.