Impaired cognitive function in Hepatitis C infected patients correlates to regional reductions of resting glucose metabolism

Question: Among patients with chronic hepatitis C virus (HCV) infection liver cirrhosis is rarely observed whereas extrahepatic manifestations such as fatigue and neurological symptoms occur in about 50%. Aim of the study was to look for alterations of cerebral glucose metabolism in HCV infected patients with only mild if any liver disease and its correlations to cognitive dysfunction and fatigue.

Methods: Nineteen female patients (51±7 years) who had been infected with HCV via immunoglobulines for Anti-D-prophylaxis in 1978/79 completed depression, fatigue and quality of life questionnaires, psychometric tests and MRI. A subgroup (n=15) and 11 healthy controls of comparable age underwent dynamic F-18-FDG PET (positron emission tomography). Using Patlaks graphical method parametric maps of the metabolic rate of glucose (MRGlc) were generated. Data analysis (group comparisons, correlations between MRGlc and psychometric test results) was done using Statistical Parametric Mapping (SPM2, Wellcome Department, London). Psychometric test results were compared to normal data and to results from a group of 20 healthy controls adjusted for sex and age.

Results: In comparison to controls patients showed significantly worse results in questionnaires and most of psychometric tests, and also significant reduction of MRGlc in the frontal lobe, cerebellum, limbic system, central region and anterior cingulate gyrus irrespective of their virus replication status. Fatigue scores showed negative correlations to MRGlc in the frontal lobe, caudate, thalamus, central region, anterior and mid cingulate gyrus. Free recall performance correlated positively to MRGlc in the anterior and mid cingulate, caudate, postcentral region and temporal lobe.

Conclusion: In HCV infected patients impairment of cognitive function and fatigue correspond to a reduction of cerebral glucose metabolism in regions dedicated to attention, memory function and arousal. The results prove further evidence that the brain may be affected by HCV-infection irrespective of the virus replication status.