Cholestatic syndromes

Evaluation of abnormal liver tests in the adult asymptomatic patient

PURPOSE OF REVIEW

Liver blood tests, including bilirubin, aminotransferases, and alkaline phosphatase, are among the most commonly encountered tests in medicine. With roles including the investigation of symptoms, medication monitoring, assessment of chronic disease, and routine assessment, these tests serve many purposes and result in abnormality in up to 40% of patients.

RECENT FINDINGS

The toll of liver disease continues to rise and abnormal liver tests offer an opportunity to identify hepatic disease early, when treatment is most effective and before patients suffer the potential downstream consequences of cirrhosis, portal hypertension, and hepatocellular carcinoma. By utilizing diagnostic strategies including detailed history gathering, alcohol use assessment, recognition of metabolic syndrome, and identifying patterns of liver test abnormalities, clinicians can develop a systematic approach to address abnormal liver tests. For these reasons, developing an evidence-based, systematic approach to handling abnormal liver tests is critically important.

SUMMARY

This review seeks to synthesize key elements of the best evidence, presently available guidelines, and expert opinion in drafting a strategy to aid clinicians and patients in the timely and accurate diagnosis of liver disease for the adult asymptomatic patient with abnormal liver tests.

The amazing universe of hepatic microstructure

An informal review is presented by the author of his 50 years of involvement in practice and research in hepatopathology. Some background for the author's attitude and meandering pathway into his professional career serves as introduction to a short discussion of the main topics of his interest and expertise. Histogenesis of liver cancer was the theme of early work for a Ph.D. thesis, the results of which were lost into oblivion due to local rules and circumstances, but were rescued three decades later. His conclusions about the cells of origin of liver cancer remain concordant with the newer concepts in the field after nearly half a century. Studies in the field of chronic hepatitis became a long saga, involving the first classification of this syndrome by "the Gnomes" in 1968, histochemical investigations of viral antigens, lymphocyte subsets and adhesion molecules, and a quarter century later, the creation of a new classification presently in use. Cholestasis was a broadening field in diagnostic entities and involved the study of liver lesions, comprising pathways of bile regurgitation (including reversed secretory polarity of hepatocytes) and so-called ductular reaction. The latter topic has a high importance for the various roles it plays in modulating liver tissue of chronic cholestasis into biliary cirrhosis, and as the territory of hepatic progenitor cells, crucial for liver regeneration in adverse conditions and in development of liver cancer. Study of the embryology of intrahepatic bile ducts helped to clarify the strange appearance of the ducts in "ductal plate configuration" in several conditions, including some forms of biliary atresia with poor prognosis and all varieties of fibrocystic bile duct diseases with "ductal plate malformation" as the basic morphologic lesion.

The effect of strict blood glucose control on biliary sludge and cholestasis in critically ill patients

BACKGROUND AND AIMS

Cholestatic liver dysfunction and biliary sludge are common problems in critically ill patients. No specific strategies have been described to prevent cholestasis and biliary sludge in the intensive care unit (ICU). We examined liver dysfunction and biliary sludge prospectively in a large medical long-stay ICU population and hypothesized that tight glycemic control with intensive insulin therapy (IIT) reduces cholestasis and biliary sludge.

METHODS

This study was a preplanned subanalysis of 658 long-stay (at least a fifth day) ICU patients out of a large randomized controlled trial (n = 1200), studying the effects of IIT on the outcome of medical critical illness. Patients were allocated to either IIT (glycemia 80-110 mg/dl) or conventional insulin therapy (CIT) requiring insulin above a glycemia of 215 mg/dl. Different patterns of liver dysfunction were studied based on daily blood sample analysis, and biliary sludge was evaluated by ultrasonography.

RESULTS

On admission, cholestasis was present in 17% of patients (n = 649), increasing to 20% on d 10 (n = 347), whereas ischemic hepatitis decreased from 3.4% (n = 588) to less than 1% (n = 328). IIT significantly decreased biliary sludge on d 5 (50.4 vs. 66.4%, P = 0.01; n = 250). The difference did not remain significant on d 10 (57.4 vs. 66.2%, P = 0.29; n = 136). IIT also lowered the cumulative risk of cholestasis (P = 0.03).

CONCLUSIONS

Cholestatic liver dysfunction and biliary sludge are very common during prolonged critical illness but are significantly reduced by IIT.

Alpha-2-adrenoceptor hyporesponsiveness in isolated tissues of cholestatic animals: involvement of opioid and nitric oxide systems

In the present study, the status of alpha(2)-adrenoceptors during cholestasis was investigated by the inhibitory effect of clonidine on the electrically stimulated contractions of mice vas deferens (MVD) and guinea pig ileum (GPI). Clonidine inhibited the contractions in both tissues in a dose-dependent manner. Compared to unoperated animals, there was a significant right-shift in the clonidine concentration-curves of both tissues obtained from 5-day bile-duct ligated (BDL) animals (p < 0.01), implying the hyporesponsiveness of alpha(2)-adrenoceptors during cholestasis. Chronic treatment with naltrexone (3 mg/kg/day) reversed the right-shift induced by cholestasis in both tissues. Administration of N(omega)-nitro-L-arginine methyl ester (20 mg/kg/day) also partially reversed cholestasis-induced effect on IC(50) of clonidine. These two treatments had no effect on IC(50) of tissues from controls. Chronic yohimbine treatment (5 mg/kg/day) recovered the effect of cholestasis on MVD, but sensitized the ileum of unoperated and BDL guinea pigs to clonidine to a similar extent, providing evidence for the role of the augmented adrenergic state of cholestasis in the hyporesponsiveness of norepinephrine-releasing neurons of MVD. We concluded that cholestasis is associated with the decreased responsiveness of alpha(2)-adrenoceptors and the cholestasis-associated augmented opioidergic tone and increased NO production contribute to this process.