Behçet disease presenting with neurological complications immediately after conversion from conventional cyclosporin A to microemulsion formulation.

A 53-year-old man with Behçet disease was treated with conventional cyclosporin A (CyA), because of refractory bilateral uveitis. Immediately following the conversion from conventional CyA to a microemulsion formulation, he presented with neurological complications. The neurological findings, pleocytosis of the cerebrospinal fluid (CSF) and brainstem lesions revealed by brain magnetic resonance imaging (MRI) suggested neuro-Behçet disease. After discontinuing CyA and introducing oral prednisolone, the neurological symptoms, pleocytosis of CSF and brainstem lesions on MRI improved. Although the microemulsion formulation, which can maintain a stable level of blood CyA, is a useful agent for the control of ocular lesions in Behçet disease, the resulting abrupt increase in blood CyA level may have induced neuro-Behçet disease.