Mycoplasma pneumoniae infection is associated with various manifestations involving the central nervous system but it has never been reported as a potential aetiology of opsoclonus-myoclonus syndrome (OMS) in children.
Observation: We report on a case in a 4-year-old girl who presented neurological manifestations compatible with an OMS, after a respiratory tract disease. Aetiological investigations revealed M. pneumoniae infection as specific IgM were present in the serum (Elisa). Evolution after corticosteroid, intravenous immunoglobulins and macrolide therapy was favourable as clinical symptoms disappeared. After a 12-month follow-up, the patient has no neurological sequela.
Conclusion: M. pneumoniae infection should be added to the list of causes to be screened in OMS. Its pathophysiology remains unknown but may involve a dysimmune postinfectious mechanism.