Internuclear Ophthalmoplegia as the First Manifestation of Pediatric-Onset Multiple Sclerosis and Concurrent Lyme Disease.

BACKGROUND Internuclear ophthalmoplegia (INO) presents as a disruption of horizontal conjugate ocular movement and is an uncommon finding in the pediatric population. Its presence warrants a thorough evaluation to search for demyelinating, mass effect, inflammatory, or infectious etiologies. CASE REPORT A 15-year-old African American girl presented to the Emergency Department with acute horizontal binocular diplopia in left gaze. An ophthalmic examination revealed a right INO. She denied any fever, chills, or neck stiffness. Complete blood counts and a metabolic panel were unremarkable. Magnetic resonance imaging (MRI) of the brain and orbits revealed scattered pontine, periventricular, and subcortical white matter signal abnormalities within the left frontal lobe suggestive of active demyelination. MRI of the spinal column also demonstrated multiple areas of increased signal intensity from the C3 to C7-T1 region. Inflammatory and autoimmune studies were negative. However, her serum IgM and IgG studies were positive for Borrelia burgdorferi with negative CSF titers. Cerebrospinal fluid (CSF) analysis demonstrated mildly elevated glucose (82 mg/dL) and oligoclonal bands, but was otherwise unremarkable. She was started on intravenous methylprednisolone and ceftriaxone. She was subsequently diagnosed with pediatric-onset multiple sclerosis and started on disease-modifying therapy, with full resolution of diplopia and INO 2 weeks later. CONCLUSIONS We present a case of INO presenting as the first manifestation of multiple sclerosis in a pediatric patient with a concurrent infectious etiology. A thorough evaluation can lead to earlier identification and treatment of underlying diseases.