Posterior Reversible Encephalopathy Syndrome Triggered by a Rapid Rise of Cyclosporine Levels in a Renal Transplant Recipient.

Posterior reversible encephalopathy syndrome (PRES) is an acute neurologic syndrome characterised by headache, confusion, visual changes, seizures, and neuroimaging findings of posterior cerebral white matter oedema. Cytotoxic and immunosuppressive drugs, such as cyclosporine, are known factors associated with PRES and, along with hypertensive encephalopathy and eclampsia, are the most common causes of the syndrome. So far, studies in cyclosporine-associated PRES have not shown an association between serum cyclosporine levels and the onset of neurologic symptoms, whereas many cases seem to be related to hypertension caused by cyclosporine. We report here, a renal-transplant recipient receiving cyclosporine, who developed acute blindness and seizures 3 days after the initiation of voriconazole for pulmonary aspergillosis. The onset of PRES coincided with an acute rise in cyclosporine levels. This case illustrates that the rapid elevation of cyclosporine levels-even in the therapeutic range-may trigger the onset of PRES and clinicians should be extremely careful when introducing drugs that may interfere with cytochrome P450, especially strong P450 inhibitors such as voriconazole, which reduce cyclosporine metabolism.