Neurologic consequences of hepatitis C and human immunodeficiency virus coinfection.

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share overlapping, large worldwide distribution. The implications of coinfection are being explored because of the importance of these viruses and demographic factors that favor coinfection. The nervous system is affected by HIV in a variety of ways resulting in significant disease of all levels of the nervous system. Emerging evidence that HCV can also impact the nervous system raises concerns that detrimental interactions might occur. Several reports addressing the manifestations of coinfection support independent contributions for both HIV and HCV on central nervous system performance, but not on distal sensory neuropathy. Neuropsychological testing reveals independent contributions resulting in poorer performance in coinfection in several drug-abusing cohorts. Motor physiologic testing substantiates performance deficits from HCV in coinfected subjects as does testing in treatment naive coinfected subjects. Although ongoing deficits attributed to HCV may be seen during HIV treatment, these deficits may be less apparent in advanced HIV disease. Current evidence supports independent contributions of HCV and HIV to neurological impairment. Preliminary evidence suggests that coinfection-related impairment does not appear to accelerate HIV-1-associated cognitive disease.