[N-methyl-D-aspartate receptor antibody encephalitis: the Janus-faced disorder].

The recognition of the antibody-mediated encephalitis as a separate entity among the immune disorders of the central nervous system was one of the greatest breakthroughs of the last two decades in neurology. Unlike viral or tumor-related encephalitis, the antibody-mediated form has a good response to immunotherapy, which gives a special clinical importance to the discovery. Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is one of the first fully characterized antibody-mediated encephalitises. This article attempts to summarize the clinical features of this complex neuropsychiatric disorder with the aim to help its early recognition and to report the clinical course and the outcome of our six seropositive anti-NMDAR cases. The disease appears typically in young females and often combined with ovarian teratoma. However, the antibody production could develop without any malignancy. The course of the illness is usually monophasic, but 10% of the cases are relapsing. The anti-NMDAR encephalitis is the result of disturbed glutamatergic neurotransmission due to the internalization of the receptor-antibody complexes. The disease usually develops after a common viral infection, but recent data proved that anti-NMDAR encephalitis could also develop after herpes simplex virus-1 encephalitis. The Janus-faced clinical course of the disease is the obstacle of the early recognition. Psychiatric symptoms - like delusion, hallucination and agitation - dominate in the first, cortical phase of the illness, which are indistinguishable from the signs of primary psychosis. The true nature of the disease only reveals later, with the appearance of the basal ganglia territory and brainstem sings, such as perioral hyperkinesia and bradycardia. Further delays the diagnosis that the leading symptoms of the second phase could be interpreted as the side effects of the initial treatment. According to expert psychiatrists, the unusual dynamic of the psychotic symptoms and the lack of response to the neuroleptic drugs could lead toward the idea of the anti-NMDAR encephalitis. The final diagnosis depends on the detection of the anti-NMDAR antibody from the cerebrospinal fluid or the serum, respectively. Haloperidol is the most potent drug to treat the psychotic symptoms of the cortical phase; however due to its antidopaminergic side effect atypical neuroleptics are recommended by the experts. The immunological treatment is the administration of intravenous corticosteroid combined with plasma exchange or with intravenous IgG infusion. The immunotherapy in most of the cases is successful, but the recovery is long and it requires strong cooperation between the psychiatrists, neurologists and intensive care therapists.