Clinical manifestations and therapy of hepatic encephalopathy

Efficacy of L-carnitine in reducing hyperammonaemia and improving neuropsychological test performance in patients with hepatic cirrhosis : results of a randomised trial

OBJECTIVES

To determine the efficacy of L-carnitine in reducing hyperammonaemia and improving neuropsychological performance in patients with hepatic cirrhosis and subclinical hepatic encephalopathy (SHE).

DESIGN

Randomised, parallel group, controlled trial.

PATIENTS AND METHODS

The study enrolled 31 patients with hepatic cirrhosis resulting from hepatitis C and/or hepatitis B, alcohol abuse and other causes. Patients randomised to active treatment, received oral L-carnitine 6 g/day in two divided doses for 4 weeks. Diagnosis of SHE was based on psychometric tests (subtests of the Wechsler Adult Intelligence Scale-Revised and the Halstead-Reitan Neuropsychological Test Battery) carried out at beginning and end of study. Serum ammonia levels were measured before treatment and weekly thereafter.

RESULTS

A total of 27 patients completed the study. Sixteen patients received L-carnitine and 11 served as controls (no treatment). L-carnitine caused rapid and significant reductions in ammonia levels, sustained over the 4-week treatment period (mean reductions 60.1 and 1.4 (μmol/L in the treated and control groups, respectively). Normal ammonia levels were attained in 14 of 16 patients receiving L-carnitine. Based on psychometric test results, seven patients (43.7%) in the L-carnitine group and five (45.5%) in the control group had SHE at baseline. L-carnitine treatment for 4 weeks caused a net overall improvement in psychometric test results compared with controls. No clinically significant adverse events were reported and all patients receiving L-carnitine reported subjective improvements in their condition.

CONCLUSIONS

RESULTS of this preliminary study indicate that L-carnitine reduces hyperammonaemia and improves the clinical symptoms of SHE in patients with hepatic cirrhosis.

Diurnal rhythm returns to normal after elimination of portacaval shunting

Previous studies showed that portacaval shunting causes metabolic and behavioral changes in rats. Most metabolic changes reversed within 1-2 wk after restoration of normal circulation. However, the rate of cerebral glucose metabolism (CMRGlc) remained depressed in some areas. The question arose whether complete recovery was possible. Therefore, a long-term behavioral study was undertaken to determine the time course of recovery. Diurnal activity was monitored for 48 h each week over a period of 14 wk: 2 wk before shunting, 6 wk after shunting, and 6 wk after restoration of normal hepatic circulation. Nighttime activity was depressed within 1 wk of shunting and did not change. Normal circulation to the liver was reestablished after 6 wk. The diurnal cycle was normal 3 wk later. Thus, although recovery of the diurnal rhythm is possible, the relatively long period necessary suggests the correction of a significant structural or chemical abnormality. A study of CMRGlc was made using the behavioral study as an index of the time necessary for recovery. CMRGlc returned to normal throughout the brain 6 wk after cessation of shunting except in the hippocampus and amygdala (7-8% decrease).