Viral encephalitis: A controversies diagnosis

Objective: Encephalitis is an uncommon neurological syndrome with not clearly defined diagnostic criteria. The incidence reaches 16/100.000 children. This is a case series of viral encephalitis in an Italian paediatric hospital, focusing on diagnostic controversies. Methods: Children aged 3 months-14 years admitted for presumed or proven viral encephalitis in 2016 were retrospectively analyzed to determine demographic, clinical, laboratory, electroencephalografic (EEG) and neuroradiological features. Results: The incidence of viral encephalitis was 10,4/100.000 in our area (65.197 children). Ten patients (8 males, median age 72 months IQR25-75:18-99) were included. None of them had comorbidities. Encephalopathy was present in 8/10 patients (80%), cerebellar ataxia in 3/10 (30%) and meningeal signs in 2/10 (20%). Two out of 10 children (20%) had also generalized seizures and 1/10 (10%) transient monoparesis. Blood tests did not show abnormalities. Lumbar Puncture (LP) was performed in 8/10 patients (80%): 4/8 had pleocytosis and none of the viral Polymerase Chain Reaction (PCR) for herpesviridae resulted positive. LP was not performed in two patients because of rapid clinical improvement (<24 hours). Serology was positive in 3/10 (EBV, Mumps and Echovirus). One patient was positive for HSV IgM two weeks after recovery. PCR for enterovirus was screened in 6/10 patients' stools (60%) and it was positive in 4/6 (67%). EEG was performed in 8/10 children showing no abnormalities. Head CT (5/10, 50%) or MRI (7/10, 70%) scans did not present significant alterations. None of the patients had sequelae after discharge. Conclusion: The number of observed cases is in-keeping with the current epidemiology of paediatric viral encephalitis. Despite extensive diagnostic testing, only a presumptive diagnosis is possible in most patients, probably due to the difficulty to collect an adequate volume of cerebrospinal fluid to perform multiple viral PCR. Therefore, further microbiological investigations are needed to define the encephalitis etiology in a pediatric setting.