Isolated Sudden-Onset Trochlear Nerve Palsy Associated with Mild Novel Coronavirus Disease (COVID-19) Infection.

PURPOSE: To present a case of sudden isolated unilateral trochlear nerve palsy of new onset associated with a COVID-19 infection without a severe course.

METHODS

A 49-year-old previously healthy man suddenly noticed seeing double while going down the stairs to go out for the first time the day after the completion of medical treatment and home isolation for COVID-19. There was no systemic disease or history of trauma.

RESULTS

Magnetic resonance imaging of the brain and orbits was normal and the neurology examination revealed no pathology. The acute onset of the diplopia, the small vertical fusion amplitude, and the lack of facial asymmetry supported acquired trochlear nerve palsy.

CONCLUSIONS

Trochlear nerve palsy has rarely been reported in association with the various types of viral infections. To the best of our knowledge, this is the first case of isolated unilateral trochlear nerve palsy with no additional neurological finding or any radiological finding that is possibly associated with mild SARS-CoV-2 infection.