Neurologic Abnormalities in Human Immunodeficiency Virus Infection

, Department of Psychiatry and Neurology, Tulane University School of Medicine, New Orleans, La 

South Med J. 2001;94(3) 

In This Article

Abstract and Introduction

Neurologic abnormalities involving the central and peripheral nervous system are common in patients infected with the human immunodeficiency virus (HIV). Evidence of central nervous system infection (cerebrospinal fluid abnormalities) occurs early; however, evidence of central and peripheral nervous system dysfunction usually occurs at later stages. Neurologic manifestations may be due to chronic immunosuppression, direct neurotropic effect of HIV, or medication effects. It is important to recognize that brain and spine imaging studies are highly sensitive in detecting abnormal pathologic processes, but these studies have low specificity for establishing a specific pathologic diagnosis.

Approximately 50 million people worldwide are living with human immunodeficiency virus (HIV) infection. The major target of this virus is the immune system, including lymphocytes, microglia, and macrophages; however, the nervous system may be injured at all neuraxis levels (Tables 1 and 2).[1,2,3] The nervous system is the most commonly affected organ system. Symptomatic neurologic dysfunction develops in more than 50% of individuals infected with HIV, and neuropathologic lesions are detected at autopsy in approximately 90% of cases. This may be explained by the facts that the central nervous system (CNS) is a sanctuary site for HIV and there is poor CNS penetration of antiviral drugs due to the presence of intact blood-brain barrier.

Human immunodeficiency virus is neurotropic; it has been recovered from both central and peripheral nervous system sites, and anti-HIV antibodies have been detected in the cerebrospinal fluid (CSF). The virus invades and infects the CSF early, possibly at the time of seroconversion. Even so, clinical evidence of HIV-mediated neurologic dysfunction (ie, dementia, gait impairment) typically does not occur until late in the course of infection when there is high viral load and evidence of immunosuppression manifested by a low CD4 lymphocyte count.[4,5] Immune deficiency caused by HIV renders patients vulnerable to infections by agents (viruses, bacteria, fungi, parasites) that are of low pathogenicity and virulence in immunologically competent individuals.

The demographics of HIV infection have changed. In the 1980s, the majority of HIV-infected patients in the United States were homosexual and bisexual men and patients with hemophilia who had received multiple transfusions. Recently, the relative incidence of HIV infection in intravenous drug users and heterosexual women has increased. With improvements in antiretroviral therapy, the incidence of CNS disease has been reduced; thus, the prevalence of HIV-infected patients has increased due to increased survival. Worldwide, however, less than 5% of patients infected with HIV have access to effective antiretroviral therapy.[6]

This report reviews the specific neurologic conditions encountered by a clinical neurologist at an HIV neurology clinic during his 15-year experience as consultant to the Tulane-Louisiana State University AIDS Clinical Trial Unit at the Medical Center of Louisiana in New Orleans.

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