Neurologic and psychiatric symptoms are reported to occur in 10 to 80 percent of patients either prior to the diagnosis of systemic lupus erythematosus (SLE) or during the course of their illness [1-5]. The wide range in reported prevalence reflects in part the use of different criteria for neuropsychiatric disease. Similarly, the reported frequencies of individual neurologic and psychiatric manifestations also vary widely, depending in part upon the population studied, the case definition used, and methods used for screening [6-8].
The American College of Rheumatology (ACR) has formulated case definitions, reporting standards, and diagnostic testing recommendations for 19 neuropsychiatric SLE syndromes (table 1) . The full definitions can be found at the following Internet address: www.rheumatology.org/publications/ar/1999/aprilappendix.asp?aud=mem.
The frequency of neuropsychiatric symptoms appears to be increasing because of both better testing and increased clinician awareness . The neuropsychiatric manifestations of SLE are varied and may be classified as primary neurologic and psychiatric disease (eg, related to direct involvement of the neuropsychiatric system) or secondary disease (eg, related to complications of the disease and its treatment) (table 2). The latter are generally more common causes of neuropsychiatric symptoms and can be produced by a variety of mechanisms (table 3).
This topic discusses the pathophysiology, clinical manifestations, diagnosis, and treatment of neurologic manifestations of SLE. The diagnostic approach to patients with neuropsychiatric manifestations is presented separately. Other clinical manifestations of SLE are also discussed separately. (See "Diagnostic approach to the neuropsychiatric manifestations of systemic lupus erythematosus" and "Overview of the clinical manifestations of systemic lupus erythematosus in adults".)
Systemic lupus erythematosus (SLE) may affect the nervous system at multiple levels, with differing neuropathology. Identification of these diverse pathophysiologic mechanisms has helped to uncover possible mechanisms of immune-mediated neuropsychiatric disorders and has permitted more accurate and effective therapy. For the purposes of this discussion, the term lupus cerebritis is used to refer to the neuropsychiatric manifestations of lupus that appear to have an organic basis, rather than a specific pathophysiologic mechanism.