BNT162b2 is one of the effective COVID-19 vaccines. However, some researchers have also reported some neurological adverse events after the vaccination. Here, we present a case of a 52-year-old female who developed aquaporin (AQP) 4-IgGpositive neuromyelitis optica spectrum disorder (NMOSD) 14 days after the first dose of BNT162b2. She experienced the neck pain, weakness of the left arm and leg, numbness of the left hand, and impaired temperature sensation of the right leg. MRI showed T2WI hyperintense lesions in the area postrema and cervical spinal cord ranging from C1 to C6 level and Gd-enhanced lesions from C3 to C5 level; especially left lateral column was predominantly enhanced. Cell-based assays showed anti-AQP4 antibody (AQP4Ab) was positive. We diagnosed AQP4-IgG-positive NMOSD. After high-dose glucocorticoid therapy, she is showing improved symptoms. The present case was characterized by the findings that a Gd-enhanced lesion in the cervical cord localized dominantly at the left lateral column, consistent with the side of the shoulder where the vaccine was injected. Many studies suggested that AQP4-IgG-positive NMOSD development has multistep mechanisms following the blood-brain barrier (BBB) breakdown. We suspected that immune responses following vaccination lead to BBB disruptions. Through the limitedly damaged BBB, the plasma cells producing AQP4Abs might be recruited to CNS, and AQP4Abs might bind to the cervical cord and the area postrema. A population-based study revealed that neurological events following COVID-19 vaccination were less likely to be observed than COVID-19 infectious symptoms. Considering rare adverse events, clinicians need to observe any changes in patient condition.

BNT162b2 is one of the effective COVID-19 vaccines. However, some researchers have also reported that the vaccines caused some neurological complications. Here, we present a case of a 52-year-old female who developed aquaporin (AQP) 4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) fourteen days after the first dose of BNT162b2. She experienced pain of the neck, weakness of the left arm and leg, numbness of the left hand, and impaired temperature sensation of the right leg. MRI showed T2WI hyperintense lesions in the area postrema and cervical spinal cord ranging from C1 to C6 level, and Gd-enhanced lesions from C3 to C5 level; especially left lateral column was predominantly enhanced. Cell-based assays showed anti-AQP4 antibody (AQP4Ab) was positive. We diagnosed AQP4-IgG-positive NMOSD. After high-dose glucocorticoid therapy, she is showing improved symptoms. The present case was characterized by the findings that a Gd-enhanced lesion in the cervical cord localized dominantly at the left lateral column, consistent with the side of the shoulder where the vaccine was injected. Many studies suggested that AQP4-IgG-positive NMOSD development has multistep mechanisms following the blood-brain barrier (BBB) breakdown. We suspected that BNT162b2-associated immune responses lead to BBB disruptions. Through the limitedly damaged BBB, the plasma cells producing AQP4Abs might be recruited to CNS, and AQP4Abs might bind to the cervical cord and the area postrema. A large population-based study revealed that BNT162b2-associated complications were less likely to be observed than COVID-19 infectious symptoms. However, considering the present case, neurologists need to observe the conditions following vaccination.

国立病院機構水戸医療センター呼吸器科， 2) 同 神経内科 Case Report；A case report of cefepime encephalopathy in small cell lung cancer patients with brain metastasis.