Seronegative autoimmune encephalitis associated with COVID-19: case report

Autoimmune encephalitis has been reported to be temporarily associated with different previous viral infections, but to date its association with COVID-19 has been rarely described. The case of a 47-year-old, self-sufficient woman with no history of COVID-19 vaccination, with respiratory symptoms and a positive antigen test for SARS CoV-2 infection, is reported. She was initially seen at the ER of a local hospital, with a history of heteroaggressiveness, akinetic mutism, epileptic crisis, and hyperreflexia. Negative infectious, autoimmune and neoplastic tests. The autoimmune encephalitis panel in CSF was negative. We administered empirical treatment with methylprednisolone and immunoglobulin, without a favorable therapeutic response; so treatment with cyclophosphamide was initiated with a favorable clinical evolution, but with severe residual neurocognitive manifestations. The fact that the initial clinical presentation was severe and unresponsive to first-line treatment despite being timely employed, could indicate a greater probability of long-term sequelae.