Posterior reversible encephalopathy syndrome: A rare complication of rituximab therapy in rheumatoid arthritis.

Rituximab, a murine-human chimeric monoclonal antibody targeting CD20-positive B lymphocytes, has established itself as an effective and relatively safe biologic therapy for patients with refractory rheumatoid arthritis. Most common side effects associated with its use include infusion related reactions and cytopenia. Rare adverse effects such as progressive multifocal leukoencephalopathy and posterior reversible encephalopathy syndrome (PRES) have also been reported. Diagnosis of PRES following rituximab treatment requires a high index of suspicion correlated with clinical and radiological features in individuals at risk. Early diagnosis and prompt treatment is associated with a favorable prognosis. We present a case of a young man who developed PRES following rituximab administration on account of active rheumatoid arthritis. Timely diagnosis and prompt treatment ensured his uneventful recovery without residual neurological deficit.