Anti NMDA-R encephalitis induced by mycoplasma pneumoniae infection in a child

Abstract

Objective: Immune-mediated encephalitis with autoantibodies has become an important component of the differential diagnosis of patients with encephalitis. Mycoplasma pneumoniae is a common respiratory pathogen mostly affecting children and adolescents can also lead to extrapulmonary diseases such as neurological manifestations including encephalitis, transverse myelitis, acute cerebellar ataxia, opsoclonus-myoclonus syndrome and movement disorders in some of which autoimmunity or formation of immune complexes are responsible. Here we report an anti-N-methyl-D-aspartate receptor (NMDA-R) encephalitis who presented with acute-onset confusion and intractable movement disorders such as myoclonus, hemiballismus, orafasial dystonia and diskinesias. Methods: A previously healthy 4-year-old boy presented with deteriorating mental status, aggresive behaviour pattern, stimulus sensitive myoclonic jerks, oromandibular dystonia and orolingual-facial dyskinesias after a febrile period with headache and vomiting. We considered immunoteraphy with high-dose intravenous corticosteroids and exchange plasmapheres thinking diagnosis of autoimmune encephalitis associated with mycoplasma infection after seroconversion. Diagnosis relied on Anti-NMDA-R positivity. Results: The majority of autoimmune encephalitis may be associated with infections. Mycoplasma pneumoniae are the main presumed infectious pathogens. It is suggested that early-onset encephalitis is a direct-type extrapulmonary manifestation involving cytokines and late-onset encephalitis is of the indirect type involving autoimmunity. Conclusion: Various clinical neurological manifestations of mycoplasma pneumoniae may be a result of the underlying patomechanisms. Further studies in this area can help to lighten the etiology of autoimmune disorders.