Neuroleptic malignant syndrome in anti-nmdar encephalitis – A phenomenon of delayed recognition and psychotropic drug resistance

Abstract

Introduction Anti-N-Methyl-D-Aspartate receptor (Anti-NMDAr) encephalitis is an autoimmune disease that is often confused for psychiatric disorders resulting in late recognition. It presents with a constellation of psychiatric/behavioral changes, seizures, autonomic instability. It may be associated with the finding of an ovarian teratoma. When unrecognized, patients are treated with antipsychotics due to the initial presentation of psychiatric complaints. Patient We report a 43-year old nulliparous female whose presentation at the ER was suggestive of Neuroleptic Malignant Syndrome (NMS) –fever, rigidity and elevated creatine kinase in the background of neuroleptic medication intake. However, it was preceded by a subacute course behavioral changes, mutism and seizures which cannot be accounted for by NMS alone. Work up excluded infectious and metabolic causes. Imaging was unremarkable. CSF studies revealed antibodies to NMDAr. Discussion Anti-NMDAr encephalitis presents with a subacute course of psychiatric complaints and are often treated with antipsychotics. Later in the course, seizures, decreasing sensorium and, dyskinesias arise. In rare instances, patients develop adverse reaction to antipsychotics and becomes a cause of emergency department consult. Anti-NMDAr Encephalitis may be confused with NMS. However, it may also co-exist at the same time. With timely recognition, complications may be prevented and immunotherapy initiated. Caution must be taken when giving antipsychotics.