Human immunodeficiency virus and cerebrovascular diseases – review

Human immunodeficiency virus (HIV) is thought to increase the risk of cerebrovascular disease, although few data exist linking these two disease entities. The aetiology of vasculopathy in both adults and children with HIV remains unknown. However, it has been postulated that direct infection by HIV, immune complex depo-sition, and impaired regulation of the immune response are the likely causes. HIV-associated vasculopathy in the cerebral circulation encompasses several forms of arterial disease occurring in the absence of any cause other than HIV infection. It includes disease of extracranial large arteries, intracranial medium sized arteries with or without aneurysm formation and small vessel disease. The pathology appears to differ across vessel types, and the exact mechanism by which HIV induces vessel wall damage in each case remains uncertain. Furthermore, immunosuppression sec-ondary to HIV can predispose to opportunistic infections of the central nervous sys-tem. These acquired immune deficiency syndrome (AIDS)-defining infections include toxoplasmosis, cryptococcal meningitis, tuberculosis, cytomegalovirus, and progres-sive multifocal leukoencephalopathy secondary to JC virus reactivation, which can also present as cerebrovascular-like manifestation in patients with HIV. Although sev-eral causative mechanisms have been proposed for the relationship between HIV in-fection and cerebrovascular diseases, including HIV-associated dyslipidaemia, endo-thelial dysfunction, inflammation, and hypercoagulability, the pathogenesis of HIV-vasculopathy is not completely understood. Beside the above pathological entities, HIV itself has been implicated in the pathogenesis of cerebrovascular dis-eases, either through direct invasion and vessel wall destruction or cytokine-mediated vascular remodelling.