A Case Report and Literature Review on Positivity for Multiple Antibodies: Autoimmune Encephalitis in Focus.

Autoimmune encephalitis (AE) is a group of neuropsychiatric disorders caused by antibodies that target the neuronal surface, synaptic, or intracellular antigens, impairing brain function. Although AE can affect people of different age groups, the occurrence of AE within specific age brackets depends on the specific type of AE and the antibodies produced. While AE is frequently considered a paraneoplastic syndrome linked to cancer, it is essential to acknowledge that the intensity of this association can vary depending on the specific antibody, leading to diverse relationships with paraneoplastic syndromes. Numerous cases have been recorded where AE manifests without an underlying malignancy. The diagnostic criteria for AE are characterized by a subacute deterioration of cognition, altered mental status, or psychiatric symptoms. Immunotherapy is recommended as a treatment for the condition, and the prognosis varies depending on the subtype. In this case, we present the case of an elderly woman who showed acute mental status changes, psychiatric symptoms, EEG alterations, and positive antibody results in both serum and CSF. Our case breaks new ground as the first documented instance of a female with positive serum anti-LGI 1, anti-AMPAR2, anti-Ri, and anti-CENP-A/B antibodies.