A Case of Anti-NMDA Receptor Encephalitis with Normal Findings on Initial Diagnostic Tests.

Abstract

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an immune-mediated disease, more common in females. It is often related to ovarian tumor.1 Clinically, it is characterized by rapid onset (<3 months) of diverse symptoms including abnormal behavioral change, decreased level of consciousness, speech dysfunction, epileptic seizure, autonomic dysfunction, psychosis, rigidity, and dyskinesia.1 The diagnostic criteria for definite antiNMDAR encephalitis includes the presence of immunoglobulin G (IgG) antibodies against the GluN1 subunit of NMDAR.2 However, test for antibodies is not readily accessible in many institutions and can take weeks to obtain results.2 So diagnostic tests such as cerebrospinal fluid (CSF) analysis, electroencephalogram (EEG), and magnetic resonance imaging (MRI), are used as integral supportive findings, in addition to suggestive clinical symptoms and excluding other disorders. Here, we report a patient who presented with acute onset of psychosis with normal EEG, and normal brain MRI, and non-inflammatory CSF initially.