Navigating the diagnostic and therapeutic complexities of autoimmune encephalitis

Characterized by immune-mediated inflammation of the brain, autoimmune encephalitis (AE) encompasses a diverse array of disorders, each presenting with unique as well as overlapping clinical manifestations, and underlying autoantibodies targeting neuronal and glial surface antigens. The clinical spectrum can range from subtle cognitive and behavioural changes to severe seizures, movement disorders, and altered consciousness. However, what truly sets AE apart from other encephalitides is its potential reversibility
when identified early and managed appropriately. The identification of N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis in 2007 heralded the discovery of a spectrum of immunotherapy-responsive AE. However, misdiagnosis remains prevalent despite diagnostic algorithms, resulting in unnecessary immunotherapies and delayed treatment of the correct diagnosis. AE diagnosis requires a judicious blend of diagnostic algorithms, antibody testing, and clinical acumen. Testing for antibodies against neuronal surface antigens, preferably in cerebrospinal fluid, is essential, but should be contextual to clinical relevance.
Treatment guidelines are largely based on retrospective studies due to a dearth of randomized and prospective data. However, early immunotherapy initiation has proven to be pivotal for optimal outcomes. The therapeutic landscape in AE continues to evolve with the introduction of novel targeted immunotherapies.
This review highlights the complexities, and proposes a systematic approach, to the diagnosis and treatment of AE.