Acute Pediatric Myelin Oligodendrocyte Glycoprotein (MOG) Antibody-Associated Rhombencephalitis With Multifocal Brain Involvement: A Case Report and Discussion.

Rhombencephalitis is a rare inflammatory condition involving the brainstem, with both infectious and autoimmune causes. While infections account for many pediatric cases, autoimmune etiologies such as myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) have gained wider recognition. We present a six-year-old male with no significant past medical history who presented with acute-onset ataxia, dysarthria, olfactory hallucinations, and headache with associated intermittent fever. Cerebrospinal fluid (CSF) analysis revealed leukocytosis with increased lymphocytes and monocytes, but negative infectious studies. Two days after the patient initially presented, brain magnetic resonance imaging (MRI) revealed findings suggestive of autoimmune rhombencephalitis. After administration of intravenous (IV) methylprednisolone and IV immunoglobulin G (IgG), the patient's condition drastically improved. Due to laboratory processing timelines, the myelin oligodendrocyte glycoprotein antibody (MOG-IgG) resulted positive 10 days after the patient's initial presentation and five days after the patient had clinically returned to baseline and been discharged. MOGAD in children is known to have a variety of clinical presentations, and delayed antibody test results should not postpone initiation of acute immunosuppressive therapy. Acute treatment should be initiated based on clinical and radiological suspicion to prevent persistent neurological deficits and risk of long-term disability.