Atypical Autoimmune Encephalitis: Diagnostic Challenges and Therapeutic Insights From a Case Series

Encephalitis syndromes are acute neurological emergencies characterized by altered sensorium, seizures, movement disorders, and neuropsychiatric manifestations. Autoimmune encephalitis (AE), although rare, necessitates prompt recognition and intervention to reduce morbidity and mortality. This study aimed to examine the clinical features, laboratory findings, radiological characteristics, and treatment outcomes of patients diagnosed with autoimmune encephalitis. This case series presents six patients diagnosed with autoimmune encephalitis and admitted to the Department of General Medicine at the All India Institute of Medical Sciences (AIIMS), Mangalagiri, between January 2024 and January 2025. The mean age of onset was 30.4 years. The cohort included two cases of anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis, one case with both myelin oligodendrocyte glycoprotein (MOG) and anti-NMDA receptor antibodies, one case of seronegative autoimmune encephalitis (SNAE) diagnosed based on magnetic resonance imaging (MRI) findings, one case of Rasmussen's encephalitis (RE), and one case of paraneoplastic autoimmune encephalitis (PAE) associated with lung malignancy. This study provides a comprehensive overview of clinical presentations, treatment approaches, and patient outcomes. Early diagnosis and timely initiation of immunosuppressive therapy are crucial for improving patient outcomes. Diagnosis relies on clinical assessment, neuroimaging, and antibody testing, with seronegative cases requiring a high degree of clinical suspicion for appropriate management.