Background: Globally, mass COVID-19 vaccine administration has revealed various adverse effects of the vaccine, such as various neurological symptoms, which are currently identified as a result of an excessive immune response.
Case report: A 70-year-old woman presented with progressive unilateral oculomotor nerve palsy and decreased visual acuity 12 days after receiving the Moderna COVID-19 vaccine. In adults, such palsy is typically caused by microvascular disease (ischemia) or compressive tumors. Given the temporal relationship between vaccination and symptoms and the exclusion of other possible causative factors, the patient's oculomotor nerve palsy and optic nerve involvement was considered to be related to the vaccination. Cranial nerve palsy following COVID-19 vaccination was diagnosed, and after pulse steroid and plasma exchange, the patient showed steady recovery.
Conclusion: Our patient with cranial nerve palsy following COVID-19 vaccination responded well to plasma exchange after limited improved toward steroid. This case highlights the importance of early identification and treatment of the immunological effects of COVID-19 vaccines on cranial nerves.