S91. EEG findings in Posterior Reversible Encephalopathy Syndrome (PRES)

Abstract

Posterior Reversible Encephalopathy Syndrome (PRES) is a relatively common cause of encephalopathy in the hospital setting, and the EEG findings have not been well described. The purpose of this study was to review the EEG findings in a series of patients with PRES. We retrospectively reviewed the EEGs of patients who received a diagnosis of PRES at Tampa General Hospital from January 2016 to October 2017. We reviewed the clinical presentation, MRI findings and EEG. From January 2016 to October 2017, 19 patients were diagnosed with PRES at Tampa General Hospital. Of those, 10 received at least one EEG. Four patients were male, 6 were female. The ages ranged from 21 to 87 (mean was 47). The patients had the following clinical presentations: 4 with encephalopathy (“mental status changes”), 8 with seizures, 1 with status epilepticus, 2 with vision changes, and 1 with headache (some patients had more than one symptoms). EEGs findings were as follows: 2 were normal; 2 showed intermittent generalized slowing; 3 showed continuous generalized slowing; 2 showed background slowing; 1 showed background suppression; 1 showed generalized rhythmic delta activity (GRDA); 1 showed GRDA, plus spike/sharp-wave discharges; 1 showed excessive beta activity; 1 showed lateralized periodic discharges; 1 showed generalized periodic discharges. The etiologies were as follows: 9 from hypertension, 1 secondary to eclampsia, and 3 due to tacrolimus (some were multifactorial). MRI supported the diagnosis of PRES and showed the following: 4 had bilateral parietal and occipital lobe T2 hyperintensities, 2 had bilateral occipital T2 hyperintensities, 1 had right occipital T2 hyperintensity, 1 had bilateral cerebellum and occipital lobe T2 hyperintensities, 1 had bilateral parietal, temporal, and left frontal T2 hyperintensities, and 1 had bilateral parietal, frontal, and occipital T2 hyperintensities. EEG findings in PRES are diverse, with no specific or even predominant pattern, based on this small sample size.