Systemic lupus erythematosus presenting as Guillain-Barré syndrome.

A 37-year-old woman developed progressive symmetrical weakness with areflexia, consistent with Guillain-Barré syndrome. After initially briefly responding to intravenous immunoglobulin, her weakness progressed markedly. Further investigation identified a new diagnosis of systemic lupus erythematosus with lupus nephritis. Following additional plasma exchange and corticosteroids, the lupus activity remitted and she made a complete neurological recovery.