Usefulness of early electroencephalography (EEG) in acute central nervous system (CNS) complications of children treated for oncohematological disorders

Abstract

Objective: To investigate the impact of early EEG in the diagnosis, management and prognosis of acute CNS complications in children treated for oncohematological disorders. Methods: We considered patients treated (chemotherapy and/or bone marrow transplantation) in our Department from 2007 to 2014. Inclusion criteria were: age <18 years; acute CNS complication defined as focal neurological signs and/or motor seizures and/or altered mental status; video-EEG recorded within 48 hours from onset. We retrospectively and blindly reviewed the EEGs to evaluate pattern and location of EEG abnormalities as well as their impact in diagnosis, management and prognosis. Results: Forty-one out of 443 patients presented acute CNS complications (9,3%). Thirty-six patients (24 transplanted) met the inclusion criteria. 32/36 EEGs showed abnormalities. Ictal EEG activity was observed in 5 patients (3 nonconvulsive status epilepticus, 1 nonconvulsive focal seizure and 1 burst suppression); all the nonconvulsive seizures were associated with Posterior Reversible Encephalopathy Syndrome (PRES) and required intravenous antiepileptic therapy. Twenty-seven EEGs displayed non ictal patterns: slowing in 24 (66,7%), periodic lateralized epileptiform discharges (PLEDs) in 7 (19,4%), low voltage in 5 (13,9%). Slowing was observed in children with PRES, infectious encephalitis and disease progression, PLEDs were detected only in children with PRES while low voltage pattern was found mainly in cerebral haemorrhages (3/5 patients). Mortality rate was 27,8% and low voltage pattern was associated with negative outcome. Conclusion: Our results show that EEG is a helpful tool in the diagnosis and management of CNS complications in children treated for oncohematological disorders: in particular EEG allowed us to promptly diagnose and treat nonconvulsive seizures, otherwise missed. Based on our experience, we suggest that EEG should be considered early in the diagnostic work-up of these children.