Unilateral internuclear ophthalmoplegia revealing multiple sclerosis : a case report  

Keywords
Internuclear ophthalmoplegia, unilateral, multiple sclerosis, medial longitudinal fasciculus. 

Abstract

Introduction. Internuclear ophthalmoplegia, the most common oculomotor disorder in multiple sclerosis (MS), is related to a lesion of the medial longitudinal fasciculus (MLF). It is rarely indicative of the disease and appears most often during the course of MS.

Case presentation. A 35-year-old woman presented to the emergency department one day after the acute onset of diplopia at the right lateral gaze. The patient had a total deficit of adduction in the left eye. The diagnosis of a left unilateral internuclear ophthalmoplegia was retained. A detailed patient interview revealed a one-week episode of vesico-sphincter disorders with voiding urges and urinary leakage that had occurred a few months earlier with total recovery. A cerebro-medullary magnetic resonance imaging revealed multiple demyelinating lesions of the supratentorial white matter with the presence of active and scar lesions. A cerebrospinal fluid (CSF) puncture performed showed an elevated IgG index of 0.72 but the isoelectro- focusing of the CSF proteins was not done. The criteria of Mac Donald 2017 were met and the diagnosis of MS was retained. The patient received 3 intravenous boli of Methylprednisolone at a dose of 1 gram per bolus for three consecutive days. The evolution was marked by total oculomotor recovery from the second bolus.

Conclusions. INO is the major oculomotor disorder in MS. In the case of INO, as with any functional paralysis, central nervous system imaging, and preferably a cerebro-medullary MRI, should be performed because this set of paralyses is usually indi- cative of a central pathology that can be serious.