title: Cerebral (18)FluoroDeoxy-Glucose Positron Emission Tomography in paediatric anti N-methyl-D-aspartate receptor encephalitis: A case series.
abstract: BACKGROUND
  Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a frequent and severe cause of encephalitis in children with potential efficient treatment (immunotherapy). Suggestive clinical features are behavioural troubles, seizures and movement disorders. Prompt diagnosis and treatment initiation are needed to guarantee favourable outcome. Nevertheless, diagnosis may be challenging because of the classical ancillary test (magnetic resonance imaging (MRI), electroencephalogram, standard cerebro-spinal fluid analysis) have limited sensitivity. Currently, immunological analyses are needed for the diagnostic confirmation. In adult patients, some studies suggested a potential role of cerebral (18)FluoroDeoxy-Glucose Positron Emission Tomography (FDG-PET) in the evaluation of anti-NMDAR encephalitis. Nevertheless, almost no data exist in paediatric population.
  
  
  METHODS
  We report retrospectively clinical, ancillary tests and cerebral FDG-PET data in 6 young patients (median age=10.5 years, 4 girls) with immunologically confirmed anti-NMDAR encephalitis.
  
  
  RESULTS
  Our patients presented classical clinical features of anti-NMDAR encephalitis with severe course (notably four patients had normal MRI). Our series shows the feasibility and the good sensitivity of cerebral FDG-PET (6/6 patients with brain metabolism alteration) in paediatric population. We report some particular features in this population: extensive, symmetric cortical hypometabolism especially in posterior areas; asymmetric anterior focus of hypermetabolism; and basal ganglia hypermetabolism. We found also a good correlation between the clinical severity and the cerebral metabolism changes. Moreover, serial cerebral FDG-PET showed parallel brain metabolism and clinical improvement.
  
  
  CONCLUSIONS
  Our study reveals the existence of specific patterns of brain metabolism alteration in anti-NMDAR encephalitis in paediatric population.
authors.affiliation: APHM, Timone Hospital, Paediatric Neurology Department, 13005 Marseille, France. Electronic address: stanislas.lagarde@ap-hm.fr.
authors.forename: Stanislas
authors.initials: S
authors.lastname: Lagarde
authors.affiliation: APHM, Timone Hospital, Paediatric Neurology Department, 13005 Marseille, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Lepine
authors.affiliation: APHM, Timone Hospital, Paediatric Neurology Department, 13005 Marseille, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Caietta
authors.affiliation: Aix Marseille Université, CNRS, CRN2M UMR 7286, 13344 Marseille, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Pelletier
authors.affiliation: Aix Marseille Université, CNRS, CRN2M UMR 7286, 13344 Marseille, France.
authors.forename: José
authors.initials: J
authors.lastname: Boucraut
authors.affiliation: APHM, Timone Hospital, Paediatric Neurology Department, 13005 Marseille, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Chabrol
authors.affiliation: APHM, Timone Hospital, Paediatric Neurology Department, 13005 Marseille, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Milh
authors.affiliation: APHM, Timone Hospital, Nuclear Medicine Department, 13005 Marseille, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Guedj
mesh_terms: D000293:Adolescent; D060426:Anti-N-Methyl-D-Aspartate Receptor Encephalitis / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000628:therapy; D001323:Autoantibodies / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004660:Encephalitis / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000032:analysis; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000032:analysis; D012189:Retrospective Studies
chemical_list: D001323:Autoantibodies; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose
keywords: Anti-NMDAR; Autoimmune; Brain FDG-PET; Cerebral FDG-PET; Children; Encephalitis; FluoroDeoxy-Glucose Positron Emission Tomography; N-methyl-d-aspartate; Rituximab