[A case of persistent cerebellar ataxia complicated by conversion disorder--confirmed by positive cerebrospinal fluid glutamate receptor delta2 and epsilon2 antibodies].

We recently encountered a 13-year-old girl who developed persistent cerebellar symptoms one month after mixed measles/rubella vaccination, making it difficult to distinguish this condition from conversion disorders. Severe truncal ataxia was the initial manifestation in this case. The patient had no abnormalities in objective tests but began to show extraordinary circadian variations in certain parameters. Her cerebellar symptoms were thus considered to possibly be associated with conversion disorders. Later, she tested positive for cerebrospinal fluid anti-glutamic acid receptor (GluR) delta2 antibody. The lymphocyte stimulation test yielded a positive reaction to GluRdelta2 antigen. In addition, in the chronic stage SPECT revealed reduced cerebellar blood flow. She was thus diagnosed as having persistent cerebellar ataxia due to autoimmune mechanisms and modification of cerebellar symptoms due to secondary conversion disorders. Our experience with this case suggests that checking cerebrospinal fluid for anti-GluRdelta2 antibody is possibly useful for distinguishing between conversion disorders and cerebellar ataxia due to autoimmune mechanisms.