Posterior reversible encephalopathy syndrome due to sirolimus

Abstract

Posterior reversible encephalopathy syndrome (PRES) was first described in 15 patients by Hinchey et al. in 1996.1 The most common clinical symptoms and signs included headache, altered alertness and confusion, vomiting, seizures, and visual disturbance ranging from blurred vision to cortical blindness. Neuroimaging typically showed white matter edema in the posterior portions of the cerebral hemispheres, particularly in the parieto-occipital regions. The presumed etiologies for the 15 patients included hypertensive encephalopathy (n=4), preeclampsia (n=3), cyclosporine (n=4), tacrolimus (n=3), and interferon- (n=1). With control of blood pressure and withdrawal or reduction of the immunosuppressive agent, all of the patients had resolution of symptoms within 2 weeks and neuroimaging normalized. Since the initial description of PRES, there have been a number of reports of its incidence following allogeneic bone marrow transplant in patients receiving cyclosporine or tacrolimus for graft-versus-host disease (GVHD) prophylaxis.2, 3, 4 Toxic levels of the immunosuppressive medications do not appear to be required for the development of PRES.5 In a previous report of a lung transplant recipient patient on sirolimus that developed a clinical syndrome similar to PRES, the neurotoxicity was attributed to dialysis disequilibrium syndrome.6 The patient improved with adjustment in the dialysis regimen and continued on sirolimus without recurrent neurological complaints. An association between treatment with sirolimus and PRES has otherwise never been reported. Here we present a case of PRES occurring in the setting of treatment with sirolimus for GVHD prophylaxis.