Cortical Blood Flow and Reactivity in Systemic Lupus Erythematosus

Steven G. Pavlakis, M.D., Darren R. Gitelman, M.D., Rima G. Kopelman, M.D. and Isak Prohovnik, PhD.

Published: 6 June 1996

Neurological complication of systemic lupus erythematosus (SLE) may be associated with abnormal cortical blood flow. We tested whether a technique for measuring cortical blood flow might provide useful information about the extent and nature of encephalopathy in SLE. Cortical perfusion was quantified in eighteen SLE patients by the xenon-133 regional cerebral blood flow (rCBF) technique. Vasomotor reactivity, thought to reflect vascular-reserve capacity was quantified by hypercapnic challenge in sixteen of the eighteen patients. Perfusion and reactivity were compared with groups of healthy controls and patients with major depression. Compared with sex­ and age­ matched controls, cortical blood flow was lower in female SLE patents (73mL/100 g/min vs 90 mL/100 g/min, p < .02). Cerebrovascular reserve, as measured by hypercapnic reactivity, was abnormally low in the SLE group (.57%/mmHg vs 3.35%/mmHg in depressed controls, p < .02) and negative in neurologically affected patients and those on steroids (rCBF decreased after hypercapnic challenge). We conclude that cerebrovascular dysfunction is common in SLE, and abnormal vascular reactivity is associated with neurologic symptoms and steroid treatment. Further longitudinal studies and larger samples are necessary to define the sensitivity and specificity of this finding.

Keywords: cerebral circulation, systemic lupus erythematosus, xenon-133, hypercapnia.