Abstracts

Rationale: Posterior reversible encephalopathy syndrome (PRES) is a common cause for seizures in post-transplant patients. The anti-rejection agents cyclosporine and tacrolimus are most strongly associated with this syndrome. This syndrome is usually considered to be fully reversible and not a cause of chronic epilepsy or persisting cortical dysfunction. Recently, greater heterogeneity of etiology and outcome of PRES has been postulated. To further evaluate the range of features of PRES, we retrospectively evaluated radiological and clinical characteristics of PRES in patients with different solid organ transplants in a single transplant center. Methods: We searched the database of the University of Minnesota Transplant Information Services (TIS). We searched for patients with seizures, encephalopathy and MRI. We reviewed the electronic medical records of such patients to find evidence of PRES. Among patients with PRES, we reviewed MR images, and extracted information on seizures, neurological condition and medication at the time of the PRES and clinical outcome. Results: Among 390 patients with solid organ transplants, we found 15 patients with PRES. All patients had posterior cerebral white matter edema on MRI, but many also had frontal and temporal lobe changes. Follow up MRI (averaging 7 months from acute MRI) showed complete resolution of edema in 7 patients, partial resolution in 3, a persisting lesion (parietal cortical encephalomalacia) in 1, and recurrent PRES in 1; 3 patients died or were lost to follow up. New (after PRES) neurological dysfunctions in 3 patients included hemiparesis, partial epilepsy, and mild cognitive impairment. Before the onset of PRES, 2 patients had only used mycophenolate for immunosuppression, 1 used only tacrolimus, and the others were on combinations of mycophenolate with cyclosporine or tacrolimus. Conclusions: This is the first series of PRES to find the syndrome in association with mycophenolate used as the sole immunosuppressive/anti-rejection agent. In agreement with findings of other recent series, we observed patients who sustained persisting cortical dysfunction or lesions, contradicting the putative full resolution of PRES. Acknowledgments: This study was supported by the University of Minnesota Comprehensive Epilepsy Center research fund.