Diagnostic evaluation of autoimmune encephalitis

Autoimmune encephalitis (AIE) is a complex neurological condition characterized by brain inflammation caused by autoantibodies targeting neuronal surface antigens or synaptic receptors resulting in direct antibody-mediated neuronal dysfunction. The aetiology of AIE includes malignancies and viral infections. However, significant proportion of these patients have no identifiable trigger.
The clinical presentation of AIE is varied, ranging from memory deficits and psychiatric symptoms to seizures and movement disorders. The diagnosis is typically based on a combination of supportive clinical features and diagnostic tools such as EEG, MRI, and CSF findings. The detection of antibodies confirms diagnosis of specific autoimmune encephalitis syndromes.
Early recognition and prompt treatment of AIE are crucial, as delayed intervention can result in permanent neurological damage. The primary treatment approach is immunotherapy, along with screening for underlying malignancies. With the evolving knowledge on different antibodies and their associated syndromes, it is important for clinicians to have a high degree of suspicion and rule out other differentials to ensure timely and appropriate diagnosis. Furthermore, the use of appropriate diagnostic criteria can help minimize delays in starting treatment.
This review provides an overview of the current understanding of AIE, with a focus on pathophysiology, clinical presentation, diagnostics, and treatment modalities, specifically for the most commonly encountered types of AIE associated with cell surface and synaptic antibodies.