Shang-Yi   Yen

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.

DISCUSSION:
Few cases have been reported of cranial neuropathies following with COVID-19 vaccination. There are some reports describing the development of cranial nerve palsy following Moderna and BNT vaccines.[4] However, the underlying pathophysiology remains unclear. It was postulated that nerves demyelination or localized nerve blood flow reduction was caused by immune-mediated damage. Most adverse effects of vaccines are triggered by aberrant immune responses and responses to pulse steroid therapy. Plasma exchange plays a vital role in the Guillain– Barré syndrome following SARS-CoV-2 vaccination and is also beneficial in COVID-19 vaccination–associated cranial neuropathies. Initially, our patient presented isolated unilateral oculomotor nerve palsy. Risks for vascular and infection events were less evident because brain imaging and serum and CSF analysis indicated unremarkable findings. Idiopathic inflammation was indicated, and pulse steroid therapy was administered. Bilateral visual acuity was told normal at ophthalmologic examination on day 5, however VEP on day 12 showed left prolonged P100 peak time (right, 110.7 ms and left, 168 ms), hererin both left optic nerve and oculomotor nerve palsy involvement was impressed. This humoral immune response of mRNA-based vaccines, such as Moderna, can trigger the autoimmune processes and produce antimyelin antibodies.[5] Our patient was diagnosed as having left optic and oculomotor nerve palsy following Moderna vaccine. After plasma exchange, the patient achieved a good therapeutic response. Compared with COVID-19 infection–associated cranial nerve neuropathy, the incidence of COVID-19 vaccination–associated cranial nerve neuropathy is very low.[6] Thus, the benefit of the vaccines far outweighs the risks, and the incidence of adverse effects is considerably low. Clinicians should continue to share these findings to allow further investigation of the causal relationship between vaccines and cranial neuropathies and exploration of the underlying immunologic pathophysiology. We report a rare case of COVID-19 mRNA vaccine– associated left optic and oculomotor nerve palsy treated successfully with pulse steroid and plasma exchange. Early identification and management of potential neurological complications of COVID-19 vaccines are paramount. The limitation of the case is the lack of objective VEP data after treatment and only comprising a single case, while the rarity of vaccines related cranial nerve palsy the efficacy of plasma exchange in steroid refractory cases had been illustrated. There is no totally effective vaccine without risks. Currently, the benefits of the approved COVID-19 vaccines in preventing COVID-19 are considered to outweigh their side effects.[7]