Neuroradiological Findings on Pediatric Autoimmune Encephalitis: How can Imageology Contribute to the Diagnosis? - EAP 2019 Congress and MasterCourse Porto Palacio Hotel

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¹Neuroradiology Department, Centro Hospitalar e Universitário de Coimbra, Portugal
²Centre for Child Development – Neuropediatrics Unit,, Hospital Pediátrico de Coimbra, Portugal
³Pediatrics Department, Caldas da Rainha Unit, Centro Hospitalar do Oeste, Portugal
⁴Epilepsy Center - EEG Laboratory, Hospital Pediátrico de Coimbra, Portugal

Background: Autoimmune encephalitis (AE) are a diagnostic challenge and have deserved a focus of increasing attention in pediatric age. The magnetic resonance imaging (MRI) still does not have a well-established role in the diagnosis of this pathology, since the abnormalities reported in the literature are usually nonspecific.

Objective: Characterizing imagiologically the cases hospitalized for AE in the HP-CHUC.

Methods: Retrospective review of cranioencephalic (CE) MRI images of patients, with ages between 28 days and 18 years, with the diagnosis of probable or definitive AE, between the years 2014 and 2018. Cases with diagnosis of encephalitis of Rasmussen were excluded.

Results: Six patients were identified, 4 males. From the etiological study, anti-GAD65 antibodies were identified in 1 patient and anti-Ma2 antibodies were found in another. The imaging study was performed between the 3rd and 15th days of the disease. In the 3 children with imaging abnormalities, the temporal cortex was the most frequently involved, in a unilateral way in 2 cases. CE-MRI revealed slight cortical thickening, without other associated anomalies, in 2 patients. In the other case with imaging abnormalities, in which anti-GAD65 antibodies were identified, hyperintense lesions were observed in T2 FLAIR, involving the parahippocampal gyrus, splenium of the corpus callosum and amygdala, suggesting the diagnostic hypothesis of limbic encephalitis. There was no enhancement of the lesions in any of the cases. One patient presented partial regression of the lesions in the control CE-MRI.

Conclusion: In this study, half of the patients had a normal CE-MRI, as reported in the literature. Although in many cases there is no imagiological changes in AE, neuroimaging has a fundamental role in the exclusion of other pathologies involving CNS and the involvement of limbic structures may evoke this diagnosis, although there are still no specific imagiological standards guiding the diagnosis in this pathology.