Bilateral internuclear ophthalmoplegia associated with SARS-COV2 infection

Background and aims: Internuclear ophthalmoplegia (INO) can be caused by a multitude of mechanisms leading to lesion of the medial longitudinal fasciculus (MLF), including infection. Currently, neurological manifestations have been described in COVID-19 patients, either due to immune mediated response or direct viral invasion of the central nervous system. Methods: Report of a clinical case Results: A previously healthy 54-year-old male presented with complaints of sudden onset dizziness and diplopia, preceded by self-limited diarrhea the day before. At examination the patient was apyretic. Neurological examination was striking for a hypertrophic right eye and a bilateral INO, but was otherwise unremarkable. Brain computed tomography scan with contrast was normal, as well as standard blood tests. RT-PCR for SARS-Cov2 was negative, as tests for HIV, VDRL, hepatitis A, B and C viruses, CMV, Borrelia, botulism and IGRA test. Stool microbiologic study was negative. Brain MRI and CSF studies were normal. Autoimmunity panel tests, including acetylcholine receptor antibody, anti-MuSK, anti-GQ1b and onconeural antibodies, were within normal range. A 5-day course of high-dose intravenous methylprednisolone was started, with progressive symptoms improvement and resolution of diplopia. One week after discharge, a serologic COVID-19 test was requested, which was positive for IgG and IgM, with a negative RT-PCR test. Conclusion: In this case, despite the lack of imaging findings, namely in the brainstem, the dramatic clinical response to anti-inflammatory therapy seems to favor an immune mediated mechanism. After extensive negative workup, the serologic positive test suggests a potential relationship between a bilateral INO and SARS-Cov2 infection.