Anti-N-methyl-D-aspartate receptor encephalitis with positive serum antithyroid antibodies, IgM antibodies against mycoplasma pneumoniae and human herpesvirus 7 PCR in the CSF.

We report the case of a boy with an encephalopathy associated with extrapyramidal and psychiatric symptoms and anti-N-methyl-D-aspartate receptor antibodies. He had positive serum antithyroid antibodies, IgM antibodies against Mycoplasma pneumoniae and human herpesvirus 7 polymerase chain reaction in the cerebrospinal fluid. He was successfully treated with rituximab, after steroids, intravenous immunoglobulin and plasma exchange. The pathophysiology of this disorder may be post-infectious and autoimmune.