[Value of whole-body MRI in vertebral fractures]. / Intérêt de l'IRM corps entier dans les fractures vertébrales.

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease in children. Pathological vertebral fracture may be the first symptom revealing this disease. We describe the case of a 14-year-old boy, with no significant past medical history, who had a sudden dorsal pain after carrying a friend on his back. Plain radiographs and MRI showed fractures of the superior endplate of T5 and T6 associated with a mild degree of kyphosis. MRI allowed ruling out discitis. The diagnostic hypotheses raised were cancer (lymphoma, leukemia), Langerhans cell histiocytosis, osteogenesis imperfecta, and CRMO. A whole-body MRI (wbMRI) was performed and disclosed several clinically silent signal abnormalities in key sites of CRMO (pelvic bone and tibial metaphyses). We point out that CRMO should be systematically added to the list of possible diseases in case of vertebral fracture. In this perspective, wbMRI is a major noninvasive tool to assess the diagnosis of CRMO, and allows avoiding a bone biopsy in most cases.

[Two pediatric cases of anti-NMDA receptor antibody encephalitis]. / Deux cas pédiatriques d'encéphalite auto-immune à anticorps anti-récepteur NMDA.

Although less frequent than viral encephalitis, anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a frequent form of acute pediatric encephalitis. After a prodromal phase of flu-like symptoms, psychiatric symptoms predominate - agitation, anxiety, hallucinations - and can make correct diagnosis more difficult. Also noted are abnormal dyskinesia and dystonia-like movements, partial seizures, difficulties talking or memorizing, and autonomic manifestations. The presentation of two cases of anti-NMDAR encephalitis illustrates the symptoms of this disease. Although the CSF abnormalities are not highly specific of this disease, and MRI most often normal, EEG shows more specific signs. These observations enable us to discuss different treatment options and understand the progression of this disease.