Isolated Abducens Nerve Palsy in a Patient With COVID-19: A Case Report and Literature Review.

Introduction: The pandemic of coronavirus disease 2019 (COVID-19) stands as a major global health and social burden. As cases are growing, several other symptoms, besides the typical respiratory ones, are emerging. The involvement of the nervous system is increasingly recognized with manifestations ranging from hyposmia to meningoencephalitis and cranial neuropathies.

Case Report: We report the case of a 41-year-old female patient who presented to the emergency department complaining of diplopia and headache over the last 2 days. She denied any medical history, as well as any other neurological or respiratory symptom. A detailed neurological and ophthalmological examination revealed a limitation to the abduction of the right eye due to palsy of the right lateral rectus muscle causing painless, horizontal diplopia in the right gaze. The computed tomography of the brain was normal. Based on the detected lymphopenia, she was tested for COVID-19 and was positive. The cerebrospinal fluid analysis showed no abnormalities, while also a repeated head computed tomography was similarly normal. The patient received no specialized medical treatment, and after 6 days, she was discharged home having a minimal degree of persistent diplopia. Two weeks later, brain magnetic resonance imaging was performed that was similarly unrevealing.

Conclusions: Isolated abducens nerve palsy can be the only presenting symptom in COVID-19. Although several pathophysiological mechanisms have been proposed, the exact nature of this manifestation has not been clarified yet. Vigilance is required by neurologists to detect and manage patients with such subtle clinical presentations.