Investigation and Presentation of Autonomic Neuropathies in HIV Infection

Abstract

The autonomic nervous system is a complex and widespread neuronal network with multiple functions. Autonomic dysfunction predisposing to orthostatic hypotension may be quite common in HIV infection, as several studies have shown impaired ability to maintain blood pressure. Autonomic testing is used both to confirm that autonomic dysfunction is present and to delineate the anatomical and physiological distribution of the deficit. This chapter reviews the ways in which these tests have been used to evaluate autonomic dysfunction in human immunodeficiency virus (HIV) infection. Although, in general, the severity of autonomic dysfunction correlates with advancing HIV infection, the progression in individual patients is less clear and appears slow. The transient appearance of hyperactive autonomic function may occur for a limited period over weeks to months in patients with autonomic nervous system degeneration, probably secondary to denervation supersensitivity. The exaggerated normal response observed in the early stages of HIV infection may reflect this phenomenon. The peripheral nervous system is involved in up to 80% of patients with AIDS, with 95% involvement noted postmortem. Although it may present at any stage of HIV infection, the distal sensory polyneuropathy is relatively uncommon early in the course of HIV disease and becomes more prevalent in immunologically compromised HIV-infected persons. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and mononeuritis multiplex, two other neuropathic accompaniments of HIV infection, are not likely to cause autonomic dysfunction.