Post-COVID-19 Vaccine Limbic Encephalitis: A Case Report

Abstract

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.

Keywords: autoimmune limbic encephalitis; covid-19 encephalitis; encephalitis syndrome; limbic; sars-cov-2-associated encephalitis.

Figure 1. Axial and coronal head MRI T2/FLAIR show symmetrical swollen bilateral hippocampal (yellow arrow) and claustrum (green arrow) with T2/FLAIR bright signal. The same regions of both hippocampi and claustrum demonstrate T1 relatively low signal and no significant contrast enhancement (not shown).

MRI: magnetic resonance imaging; FLAIR: fluid-attenuated inversion recovery

Figure 2. Head MRI axial diffusion and ADC map demonstrate symmetrical claustrum diffusion restriction (blue arrow).

MRI: magnetic resonance imaging; ADC: apparent diffusion coefficient