Investigators at University of Milan, Italy, report a 6-year-old boy who presented with left-sided weakness followed by status epilepticus, left-sided tonic-clonic seizures with secondary generalization, without fever. The seizure was preceded by an acute gastroenteritis in the week prior to admission. His blood pressure was 139-112 mm/Hg (>95th percentile). Control of status by iv phenobarbital was accompanied by resolution of hypertension. Neurological examination revealed hypotonia and hyporeflexia of the left side. Blood and CSF examinations were normal, including PCR for Enterovirus. MRI showed bilateral asymmetric low intensities in the white and gray matter of posterior parietal and occipital lobes, affecting the right hemisphere predominantly. EEG showed an encephalopathic pattern in posterior regions with no epileptiform discharges. The patient recovered completely within the following 6 days, and follow-up exams in 3 and 12 months were normal, including neurological, EEG, MRI, and blood pressure, and with no recurrence of seizures. 
COMMENT. Posterior reversible encephalopathy syndrome (PRES), first described in 1996 , is characterized clinically by headache, altered awareness, visual disturbance, and seizures, and radiologically by transient posterior lesions in subcortical white matter. PRES is associated with a rapid rise in blood pressure that may underlie the encephalopathy. The pathophysiology of PRES is not completely understood, but predisposing conditions include renal and hemato-oncologic diseases and use of chemotherapeutic immunosuppressive drugs . Other conditions reported in association with PRES are organ and bone marrow transplantation, autoimmune disease, Guillain-Barre syndrome, sickle cell anemia, hemolytic-uremic syndrome, and iv immunoglobulin administration.