Etiology, characteristics and outcome of seizures after pediatric hematopoietic stem cell transplantation

PURPOSE: Epileptic seizures are frequent manifestations after hematopoietic stem cell transplantation (HSCT). In this retrospective single-center study we evaluated electroclinical features and analyzed etiologies and outcome of seizures after pediatric HSCT. METHODS: Of 261 children transplanted between 2000 and 2010, we identified and analyzed data of 28 patients with seizures within a year from HSCT. RESULTS: Most frequent etiologies were posterior reversible encephalopathy syndrome (PRES, 14 patients) and central nervous system (CNS) infections (4 patients). Seizures were the presentation of the underlying complications in 22 patients. Sixteen episodes of status epilepticus were identified. Seizures secondary to PRES were usually longer and associated with non-convulsive signs. Early neuroimaging and EEG monitoring proved to be crucial to diagnose and treat seizures and their causes. No patients developed epilepsy suggesting that chronic antiepileptic therapy is not necessary in these patients. Overall survival was 32.3% over 5 years in patients with seizures and 45.8% in patients without seizures (p<0.05). Multivariate statistical analysis identified as independent risk factors for seizures a diagnosis of non-oncological disease and cord blood stem cell transplantation. CONCLUSIONS: Seizures in transplanted children are a severe event and are associated with high morbidity and poor outcome. In particular, patients with non-oncological diseases and cord blood stem cell transplantation have to be considered at high risk of seizures. Moreover, this study underlines the importance of early recognition of non-convulsive clinical signs and of EEG monitoring for a prompt diagnosis and an appropriate management of seizures and their causes.