Autoimmune encephalitis.

Autoimmune encephalitis (AE) is a treatable neuro-inflammatory disorder that is increasing in incidence. AE can be associated with malignancy (paraneoplastic), but in many patients no tumour is present. The disease presentation of AE can be heterogeneous depending on the type of antibody involved. AE is often caused by neuronal antibodies that bind to extracellular autoantigens (that is, N-methyl-D-aspartate receptor (NMDAR) and LGI1). Binding of these antibodies causes dysfunction of synaptic receptors, which leads to neurological symptoms. In these patients, treatment with immunosuppressive therapies is believed to decrease inflammation and deplete antibodies, and is essential for recovery. AE can also occur in patients with antibodies against intracellular antigens (such as Hu and Ri), often in the setting of malignancy. In these patients, tumour treatment is essential for stabilization or improvement. The most frequent symptoms of AE are cognitive problems, behavioural changes and seizures. Rapid recognition of AE syndromes is essential as earlier treatment of AE leads to better outcomes. For a definite diagnosis, the identification of an autoantibody is essential; however, some patients have seronegative AE. Most patients are severely affected during the acute disease stage, but long-term functional recovery is often good, particularly for patients without cancer. Nevertheless, residual anxiety, fatigue and cognitive problems can considerably affect quality of life. Research focuses on improving the understanding of pathophysiological processes, establishing patient-tailored outcome measures, optimizing treatment prediction models and studying different therapeutic regimens, all aiming to improve treatment and long-term outcomes.