Since its description in 2007, anti-NMDAR encephalitis has been recognized as the most frequent autoimmune encephalitis in children after acute demyelinating encephalomyelitis. In one report its frequency surpassed that of any viral encephalitis. Following a nonspecific, usually febrile disease, patients develop serum and cerebrospinal fluid antibodies to a restricted epitope region of the NRI subunit of the NMDAR. The clinical symptoms differ between age groups. Children older than 12 years of age present more often with psychiatric symptoms. During the first month of this autoimmune disease they develop also abnormal movements and language dysfunction. In contrast, children younger than 12 years of age tend to present with seizures. Additional symptoms include behavioral changes, sleep dysfunction, memory deficit, speech dysfunction, movement disorder, loss of consciousness, autonomic dysfunction and finally central hypoventilation and possibly death. Long term siquelae may include significant permanent neurologic damage manifesting as cognitive dysfunction and full-blown psychiatric illness.
Recently, anti-NMDAR antibodies were found in 25% of patients following acute Herpes Simplex Virus encephalitis. The presenting symptom was the development of chorea after recovery from the initial infectious encephalitis.
Early treatment of Anti-NMDAR encephalitis by a combination of intravenous immunoglobulins, intravenous high-dose steroids and plasmapharesis may affect outcome.
