Abstracts

Rationale: Posterior Reversible encephalopathy syndrome (PRES) manifests clinically with seizures, visual disturbances, headaches and focal neurological deficits. Multiple case reports have characterized the seizures as generalized tonic clonic seizures. The purpose of this retrospective study was to review the incidence and management of seizures associated with PRES in the inpatient setting. Methods: Hospital records of 44 adult patients with clinically diagnosed PRES treated at our hospital from July of 2011 to April of 2014 were retrospectively reviewed. We analyzed the demographics, clinical presentation, seizure semiology, seizure frequency, EEG and antiepileptic drugs (AED) used for treatment. Results: We identified 37 patients in whom MRI of the brain had confirmed the diagnosis of PRES. In our series there was a higher incidence of PRES in women (n=23, 62%). Average age was 53. Predisposing risk factor included hypertension (n=22, 59.5%), hemodialysis dependent renal disease (n=4, 10.8%), immunosuppresants (n=4, 10.8%). Seizures occurred in 25 of 37 patients (67.6%). Seizure semiology was generalized tonic clonic seizure (n=21/25 (84%), Staring spell (n=3/25, 12%), and myoclonus (n=1, 4%). AED were started in 22 of 25 patients whom had seizures . In 3 patients with seizures, no AED was started as the focus treatment was control of blood pressure. Levetiracetam being the most commonly used agent (18 of 22) and Phenytoin was used in 10. One patient was on both levetiracetam and phenytoin on discharge. 5 patients whom did not have documented seizures were prophylactically started on AED. 30/37 received at least one EEG during admission. 21 of the 30 were documented as diffuse slowing and 4/30 had focal slowing, 5 were reported to be normal. None were reported to have epileptiform discharges. Conclusions: In our case series of patient with PRES, there was a high incidence of seizures. They occurred early in course of hospitalization and GTC seizures was the predominant seizure type, with complex partial seizures and myoclonus being rare. All patients that were started AEDs did well and had no further seizures. Levetriacetam and phenytoin were equally efficacious. In small proportion of our patients treatment was focused on blood pressure control, and they also did well i.e had no further seizures even though AEDs were not started. EEG in all our patients with PRES only revealed non- specific slowing and the possible explanation is that the rapid control of BP following admission likely resolved the cortical irritability. Our experience suggests that seizures in PRES do not recur with aggressive BP control and AEDs. Long term AED may not be necessary since the EEG studies in our series did not reveal cortical irritability once the blood pressures were controlled. Further long term case controlled studies are needed to confirm our results.