Anti-nmdar paraneoplastic autoimmune-mediated encephalopathy

A 17-year-old woman with 3 days of severe headache , accompanied by flu-like syndrome and low-grade fever, which began with a generalized tonic-clonic seizure of seconds. It evolves to disorientation, psychomotor agitation, and psychiatric symptoms. Cranial CT was normal, and CSF with lymphocytosis and mild pleocytosis, PCR herpex virus, borrelia, enterovirus & zhiel were negatives She entered into the ICU , with MRI where leptomeningeal enhancement was seen.Her nurological deterioration was progressing and GCS was 9 . Serological studies for CMV, toxoplasmosis, EBV, HIV, HBV , leptospira, arbovirus ,protein 14-3-3- (prions), syphilis & oligoclonal bands, were all of them NEGATIVES Neurological situation was stagnant, with dysautonomies (sinus strikes), dyskinesias and dystonia difficult to control It was decided to extend the study of antibodies to rule out immunomediated encephalitis. Anti Yo, anti Hu were negative ,but anti-NMDAR POSITIVE. Discarding thymoma but objectifying ovarian teratoma in Body CT ?

Autoinmune -mediated encephalopathy ( AMEs) are a group of disorders caused by inflammation of the CNS , that appears initially by the interaction of autoantibodies in the CSF or serum with specific neuronal (surface or intracellular ) antigens. There are paraneoplastic causes and others that are not. Neoplasms express antigens that fits also neuronal cells antigens. Antibodies produced, are target both tumor and brain One of the most important cell surface antigen paraneoplastic AMEs is anti NMDAR, frequently associated with ovarian teratomas in young women , with acute onset of psychosis ,seizures movement disorders and autonomic instability Brain MR in more than a half of patients is normal , but the most common imaging is limbic encephalitis. Anormal enhancement of cortex , meninges and basal ganglia is rare. All the image findings usually revert with the treatmentInmunomodulatory therapy and tumor resection are the appropriate treatment, with a recovery of more than 75%

Encephalitis is a paraneoplastic AMEs and should be considered in young patients with subacute-acute presentation of psychiatric symtoms , abnormal movements and autonomic dysfunction. The brain MRI can be normal or involvement of limbic system, and before suspicion, is mandatory to request the specific antibodies and rule out tumor lesions with body CT, especially the ovarian teratoma in young women.

- Saket Ramin R., Geschwind D., Josephson S.A., Douglas Vanja C ,Hess C, et al , Autoinmune-Mediated encephalopathy : Classification , evaluation and MR imaging patterns of disease, Neurographics , June 2011, 1, 1, :2-16 - González Valcá