Limbic encephalitis (LE) diagnosis can be challenging due to its broad spectrum of clinical presentation and variety of causes. The most commonly known causes include paraneoplastic and autoimmune, but they can also occur post-vaccine. Since 2020, many people worldwide have received the coronavirus disease 2019 (COVID-19) vaccine after FDA approval. Mild self-limited neurological adverse reactions, including headache and dizziness, were reported post-vaccine. However, emerging few neurological severe events, including encephalitis, have also been reported. Herein, we present a case of a middle-aged female who presented with seizures after two days of receiving the second dose of the Moderna COVID-19 vaccine. A diagnosis of limbic encephalitis was made based on head MRI findings. It was treated with immunosuppressive agents and responded well with no additional neurological sequelae. This case is unique as it highlights a possible association between limbic encephalitis and the COVID-19 vaccine.

Vitamin B12 deficiency is a multifactorial condition, with a wide range of clinical presentations from mild to severe anemia and anemia-related neurological deficits. Hemolysis is a unique cause but has increasingly been recognized lately as a possible B12 deficiency presentation. Our patient presented with hemolytic anemia, for which extensive workup has excluded the common hemolysis etiologies. Therefore, it was attributed to B12 deficiency and improved significantly after treatment. Our case highlights the significance of this unusual presentation and its clinical implementation.