Longitudinally Extensive Transverse Myelitis With Cerebral Demyelination Following Varicella Infection in a Child: A Case-Based Analysis of Rare Neurologic Sequelae

Neurologic complications of varicella are rare but may include inflammatory demyelinating disorders. We report a 10-year-old immunocompetent male who developed rapidly progressive paraparesis evolving to quadriparesis with autonomic dysfunction and without encephalopathy following recent varicella infection. Examination revealed a sensory level at T4 with initial upper motor neuron signs progressing to areflexia. Cerebrospinal fluid showed lymphocytic pleocytosis with elevated protein, and serum varicella IgM was positive. Magnetic resonance imaging demonstrated longitudinally extensive transverse myelitis from the cervico-medullary junction to L5 with multifocal cerebral white matter involvement. Anti–aquaporin-4 and anti–myelin oligodendrocyte glycoprotein antibodies were negative. A diagnosis of longitudinally extensive transverse myelitis with cerebral demyelination was considered. The patient was treated with intravenous methylprednisolone, acyclovir, and immunoglobulin, resulting in significant clinical and radiologic improvement. This case highlights a rare parainfectious presentation of longitudinally extensive transverse myelitis with cerebral demyelination following varicella infection, emphasizing the importance of early recognition and immunotherapy in improving neurologic outcomes.