Encephalitis as a post-COVID-19 complication: causation or association?

ABSTRACT

Case Report Although the coronavirus disease 2019 (COVID-19) affects the respiratory system, neurological complications in children have been reported. Neurological manifestations in children with acute COVID-19 infection are rare and range from headaches, transverse myelitis, strokes, and encephalitis which presents as a part of Multisystem Inflammatory Syndrome in Children (MIS-C). However, encephalitis presenting post-COVID-19 in the absence of MIS-C in children has not been described. Case presentation A 9-year-old Hispanic female with no past medical history presented with altered mental status and seizures. Associated symptoms prior to seizures included worsening headaches and vomiting. Initial labs were significant for an elevated erythrocyte sedimentation rate of 32 mm/hr, C-reactive protein of 2 mg/dL, and white blood cell (WBC) count of 28 000 cells/mcl with neutrophilia. Comprehensive metabolic panel was normal. Computed tomography of the head and urine drug screen were normal. Magnetic resonance imaging of the brain demonstrated diffusion restriction in the left frontal lobe as well as mild leptomeningeal enhancement concerning for meningoencephalitis. Lumbar puncture (LP) showed pleocytosis (WBC 169 cells/mcl, 76% neutrophils), elevated glucose 77 mg/dl, normal protein 56 mg/dl, and elevated myelin basic protein indicative of a demyelinating disease. Infectious workup was significant for a positive COVID-19 immunoglobulin (Ig) G (19.66), positive Mycoplasma pneumoniae (M. pneumoniae) IgM (0.87 units/L), with an equivocal IgG (0.11 units/L). Autoimmune workup was negative. She received dexamethasone 0.15 mg/kg/dose for 1 day, followed by methylprednisolone (10 mg/kg/dose) for 3 days and oral prednisone for 5 days resulting in significant improvement. Although CSF cultures returned negative, she received a 7-day course of doxycycline for a possible coexisting M. pneumoniae infection. Repeat LP showed improving pleocytosis, and lymphocytic predominance. Discussion: In this case report, rapid neurological recovery after administration of corticosteroids in the presence of positive COVID-19 IgG and demyelinating disease was suggestive of encephalitis presenting post- COVID-19 infection. Although M. pneumoniae can present with neurological symptoms (e.g., encephalitis), repeat titers at follow-up after recovery did not show the expected 4-fold increase in IgG, making it less likely the cause of this presentation. The proposed pathophysiology of COVID-19-mediated encephalitis includes direct invasion of the nervous system, immune-mediated cytokine response, and molecular mimicry between coronaviruses and neuronal proteins causing demyelination. The mainstay treatment includes immunomodulators such as corticosteroids, Intravenous Immunoglobulin, monoclonal antibodies (eg., rituximab), or plasma exchange. Conclusion: COVID-19 infection should be considered when evaluating a patient with meningoencephalitis or post-infectious encephalitis.