Horizontal Gaze Palsy and Ipsilateral Facial Nerve Palsy in Older Patient as Initial Manifestation of Very Late-Onset Multiple Sclerosis Successfully Treated with Oral Corticosteroids: A Case Report.

Introduction: Multiple sclerosis (MS) is a demyelinating condition of the central nervous system (CNS) that primarily affects young adults. Very late-onset multiple sclerosis (VLOMS) is an uncommon form of MS, accounting for only 0.5 percent of all MS patients. Eye movement impairments such as internuclear ophthalmoplegia are common in MS, while horizontal gaze palsy is an uncommon occurrence. Case Presentation: We report a case of a patient diagnosed with VLOMS who presented with left horizontal gaze palsy and ipsilateral facial nerve palsy. Brain magnetic resonance imaging showed Dawson's fingers in the left and right periventricular white matter; multiple small, round, hyperintense lesions in the left and right cortex and juxtacortical cerebellar hemisphere; and small hyperintense lesion in the left paramedian pontine reticular formation, suggesting the diagnosis of MS. Oral corticosteroids led to complete resolution of ocular movement and ipsilateral facial nerve palsy. Conclusion: We propose that neuroimaging should be performed in ophthalmoplegia with a pattern representing CNS lesion and oral corticosteroids may be an effective alternative to high-cost intravenous corticosteroids.