A case of central nervous system lupus in succession to lupus peritonitis: a difficulty in the differential diagnosis between lupus psychosis and steroid-induced psychosis

A 55-year-old woman with well-controlled systemic lupus erythematosus (SLE) suffered from the abrupt onset of massive intractable ascites, which did not respond to conventional diuretic therapy. While treatment with methylprednisolone pulse therapy ameliorated this lupus peritonitis, neuropsychiatric symptoms then appeared. After a diagnosis of the central nervous system (CNS) lupus, pulse therapy was continued and the patient recovered from the lupus psychosis. We discuss the differential diagnosis between CNS lupus and steroid-induced psychosis with particular references to recent diagnostic methods for CNS lupus.