Investigators at Children's Hospital of Montefiore, Albert Einstein College of Medicine, NY, determined the incidence of posterior reversible encephalopathy syndrome (PRES) in a pediatric critical care unit. Ten patients <21 years of age with PRES (incidence of 1 in 259 admissions, 0.4%) were studied. Nine patients presented with generalized tonic and/or clonic seizures. Continuous EEG showed generalized slowing but no epileptiform activity. Risk factors included hypertension, cytotoxin medication use, and anemia. Comorbidities included systemic lupus erythematosus, inflammatory bowel disease, ulcerative colitis, liver cirrhosis, pulmonary embolism, renal insufficiency, septic shock, and acute chest syndrome. One-year follow-up showed no residual neurological deficits and resolution of white matter signal abnormalities on neuroimaging. [1]

COMMENT. PRES, also referred to as hypertensive encephalopathy or reversible posterior leukoencephalopathy syndrome, is a clinical syndrome that results from disruption of the blood-brain barrier and vasogenic edema, demonstrated on MRI with hyperintense signals in the posterior cerebral white matter.

PRES in an infant 35 days old is reported from the Mayo Clinic. The syndrome is rare in children less than 1 year. The infant had a history of obstructive sleep apnea, laryngomalacia, and choanal atresia. While undergoing bronchoscopy, she developed apneic episodes with stiffening of extremities. EEG revealed occipital lobe onset seizures, and MRI showed hyperintense T2 signal in both posterior temporal and parieto-occipital lobes. A labile blood pressure was normalized and seizures abated with fosphenytoin and levetiracetam. At 3 month of age, resolution of MRI abnormality confirmed the diagnosis of PRES. [2]

PRES and risk of epilepsy. The incidence of subsequent epilepsy was 2.25 fold higher in patients with hypertensive encephalopathy (HE) than in controls, in a nationwide population-based study in Taiwan. The incidence of epilepsy was higher in men, younger patients with HE, and in those with brain disorders. [3]