Autoimmune encephalitis

The diagnosis of autoimmune encephalitides is generally based on a combination of the characteristic clinical picture, supporting findings from brain MRT, EEG and CSF analysis if necessary, and antibody determination in serum/CSF. Monospecific recombinant assays are the method of choice for serological diagnostics and can be combined with conventional immunohistochemical detection procedures. The following conditions must be excluded by differential diagnostics: infectious encephalitides (especially HSV), other autoimmune etiologies (e.g. limbic encephalitis with autoantibodies against Hu, Ma2, CV2, amphiphysin) and clinically similar diseases of the central and/or peripheral nervous system. A diagnostic discrimination from atypical encephalitides should also be taken into consideration. It should be considered that overlap syndromes and combinations of different syndromes can also occur. When a positive serological result is obtained, a comprehensive tumor investigation should be undertaken.

The frequency of underlying tumors ranges from 10 to 70%, depending on the type of antibody. The antibodies most likely play a causal role in the pathogenesis. Since appropriate therapy (immunomodulatory intervention, tumor resection) results in considerable regression of symptoms in most patients, early diagnosis is important for a favorable prognosis.