The central nervous system in systemic lupus erythematosus. Part 2. Pathogenetic mechanisms of clinical syndromes: a literature investigation.

OBJECTIVES: To identify the pathogenetic mechanisms of central nervous system (CNS) syndromes of systemic lupus erythematosus (SLE) as described in the literature.

METHODS: Using PUBMED, we performed a systematic search of publications from 1980 onwards. Studies were eligible if they had been performed on patients or material from patients with CNS manifestations and definite SLE and when the CNS manifestations were not secondary. Criteria were formulated for the identification of pathogenetic mechanisms.

RESULTS: The single most important cause of the CNS syndromes of SLE is ischaemia due to narrowing or occlusion of small vessels, arteries and veins. Antiphospholipid antibodies and premature atherosclerosis play roles in these processes, but they have not been delineated definitely. Intracranial and intraspinal haemorrhages are much less frequent than ischaemia and are presumably in part due directly to SLE. Vasculitis may cause ischaemia or haemorrhage in the CNS and is involved occasionally, as shown by imaging and histological findings. White matter damage is heterogeneous and ill-understood. It includes white matter degeneration and myelin vacuolation of the spinal cord, and reversible leucoencephalopathy due to oedema. Antibody-induced neuronal dysfunction in the CNS is a realistic hypothesis and may involve anti-ribosomal P antibodies and several other antibodies. Deficiency of psychological reactions forms a separate and entirely different category of mechanisms.

CONCLUSIONS: Causes have been identified or possible causes have been suggested for most of the CNS syndromes of SLE, thus offering rationales for different forms of prevention and therapy.