Isolated Abducens Nerve Palsies from COVID-19 Infections: Clinical Features and Outcomes.

Background: Isolated abducens nerve palsies from COVID-19 infections are rarely described in literature. Their clinical features are poorly understood, and guidance on their treatment is lacking.

Objective: To describe the clinical features of isolated abducens nerve palsies from COVID-19 infection, and provide guidance on their management.

Methods: We performed a literature review and analyzed the clinical features of patients with isolated abducens nerve palsy from COVID-19 infections reported in literature.

Results: In total, 16 cases from 15 studies published between January 2020 and December 2023 were identified. Their median age was 44 years (range 3-71, including two children). Nearly two-thirds (10/16, 63%) were without medical history. Abducens nerve palsies mostly occurred early with COVID-19 symptoms (median of 5.5 days, range 0-21 days). They were all unilateral, and displayed neither clear gender nor left-right predilections. Brain magnetic resonance imaging scans were often unremarkable (9/13, 69%). More than half (9/16, 56%) received no treatment or symptomatic treatment only, while only two received steroids. Regardless, nearly all experienced clinical of diplopia (14/16, 88%), of which most recovery were either complete or near-complete (at least 10/14, 71%) within a median period of 26 days (range 5-240 days).

Conclusion: Isolated abducens nerve palsies are early but uncommon complications of COVID-19, mainly affecting patients with mild infections. Prognosis appears fair even when without corticosteroid treatment, and recovery is significant and early in most. Observation and early outpatient clinical review within a month are reasonable measures. Patients without significant improvement within a month should be re-assessed for other aetiologies.