Intravenous Immunoglobulin as a Therapeutic Option for Mycoplasma pneumoniae Encephalitis

Objective: To analyze the outcomes of a cohort of children diagnosed with Mycoplasma pneumoniae encephalitis whose treatment regimens included intravenous immunoglobulin (IVIG). Methods: A retrospective study was performed at a single center between 2011 and 2016 of children diagnosed with Mycoplasma pneumoniae encephalitis whose acute treatment regimen included IVIG. Details of therapeutic interventions and the clinical course were retrieved from medical records via an institutionally approved protocol. The modified Rankin score was used to quantify outcomes. Results: Four children met inclusion criteria, 3 of whom had prodromal symptoms of infection lasting 5 to 7 days before onset of their neurologic symptoms. One patient presented with neurologic symptoms with no clinical prodrome. The initial treatment regimen included systemic corticosteroids, antibiotics, or both. IVIG was administered for a total dose of 2 g/kg divided over 2 to 4 days to all 4 children. All children showed clinical improvement after IVIG. The 3 children with prodromal symptoms showed immediate and dramatic clinical improvement after IVIG therapy. Discussion: The immediate response to immunomodulatory therapy in the patients with prodrome suggests that the neurologic syndrome may be caused at least in part by an autoimmune process. The child who did not respond to IVIG had no prodrome, and also had normal electroencephalographic (EEG) and brain magnetic resonance imaging (MRI) findings. These cases suggest that early administration of IVIG should be considered in patients suspected of having Mycoplasma encephalitis, particularly in those who have had prodromal symptoms.