Development of chronic epilepsy after recurrent episodes of Posterior Reversible Encephalopathy Syndrome associated with Periodic Lateralized Epileptiform Discharges

Posterior Reversible Encephalopathy Syndrome (PRES) is a syndrome comprising headache, altered mentation, and seizures, associated with neuroimaging findings characteristic of subcortical edema in the posterior regions. It is usually seen in patients treated with immunosuppressants, in renal failure, or with eclampsia. Recurrent episodes of PRES in the same patient are rarely observed. Although seizures are often seen in PRES, EEG findings are not well described and include generalized and focal slowing with epileptiform discharges; there are limited reports of Periodic Lateralized Epileptiform Discharges (PLEDs) occurring during PRES, and there are no reports of PRES associated with PLEDs with subsequent development of epilepsy. We report a patient we followed for one year with recurrent episodes of PRES associated with posteriorly dominant independent bilateral PLEDs who subsequently developed epilepsy. Patients with PRES and PLEDs should be treated aggressively with anti-hypertensive and anti-epileptic agents in order to avoid potential complications. Although PRES is typically thought of as a reversible syndrome, this case illustrates that PRES may have serious long term sequelae after the reversible syndrome has resolved. This case highlights the importance of aggressive management of PRES as well as the prevention of subsequent episodes of PRES as patients may develop permanent brain dysfunction.