P3.211: Neurological Presentations in Mycoplasma pneumoniae Infections: A Case Series from the Recent Outbreak at a Children's Hospital

Introduction: Mycoplasma pneumoniae is a key cause of atypical pneumonia in children and young adults, but it can also trigger extrapulmonary complications involving the nervous, cardiac, dermatologic, and hematologic systems. Since the COVID-19 pandemic, global outbreaks—especially in children—have been reported with increasing severity and rising resistance to macrolides. In late 2023, the U.S. noted a 9-fold rise in cases. We share our experience with a case series of an unusual presentation of neurological symptoms associated with Mycoplasma infections, exploring our diagnostic approach and treatment strategies.

Case Description: We report four pediatric cases of Mycoplasma pneumoniae-associated neurological complications presenting with acute-onset focal or diffuse neurologic deficits, including sensorimotor impairment, altered mental status, and encephalopathy. All patients had recent mild respiratory symptoms and showed evidence of systemic inflammation, with elevated CRP and leukocytosis. Chest imaging revealed pneumonia in multiple cases, and all had positive Mycoplasma IgM serology. Neuroimaging consistently demonstrated demyelinating lesions, and CSF analyses were notable for pleocytosis and elevated protein, without identifiable pathogens on culture or PCR. Despite initial empiric antimicrobial and antiviral therapy, clinical improvement was limited until escalation to immunomodulatory treatment, including corticosteroids and plasmapheresis. All patients ultimately experienced significant neurologic recovery.

Discussion: Neurological complications of Mycoplasma pneumoniae are likely immune-mediated rather than due to direct CNS invasion. Proposed mechanisms include post-infectious demyelination via molecular mimicry, cytokine-mediated vasculitis, or autoantibody formation. In our cases, CSF cultures and PCR were negative, but inflammatory markers, demyelinating patterns on MRI, and positive Mycoplasma IgM supported a post-infectious process. Limited response to antimicrobials and marked improvement with steroids and plasmapheresis further supported an autoimmune etiology.

Conclusion: Neurological complications of Mycoplasma pneumoniae in children, while rare, can present with significant demyelinating syndromes. Early recognition, thorough diagnostic evaluation, and prompt initiation of immunomodulatory therapy are key to improving outcomes.