Anti-NMDA Receptor Encephalitis: A Need for Increased Awareness Among Psychiatrists

Copyright © SLACK Incorporated ABSTRACT Anti–N-methyl-D-aspartate (NMDA) receptor encephalitis may present with a wide variety of early neuropsychiatric symptoms such as psychosis, insomnia, catatonia, and agitation, and at times in the absence of fever. The literature highlights the vital role of psychiatrists in early recognition and timely treatment of this condition. Presence of immunoglobulin G antibodies in blood and cerebrospinal fluid (CSF) against the NR1a subunit of the NMDA receptor is considered the gold standard for confirming diagnosis. There may be other nonspecific findings in CSF and on electroencephalogram and brain magnetic resonance imaging. Management includes surgical removal of the tumor if identified, firstand secondline immunotherapy, supportive medical care, and management of psychiatric symptoms. The role of electroconvulsive therapy has been noted for treatment of catatonic symptoms in particular. [Psychiatr Ann. 2015;45(11):572-576.] Glutamate is the primary excitatory neurotransmitter in the brain. The N-methyl-Daspartate (NMDA) receptor, is an ionotropic glutamate receptor on neuronal membranes that is highly permeable to Ca2+. The activation of these receptors requires the binding of two coagonists, glycine and L glutamate. Glycine acts as a modulator whereas glutamate is the active neurotransmitter. These receptors are found in many cortical and subcortical brain regions, with a higher concentration in the hippocampus. In the hippocampus, NMDA receptors are involved in spatial learning and long-term potentiation, thus explaining their role in learning and memory. Hyperactivity of NMDA receptors can lead to neurotoxicity and is possibly involved in the pathophysiology of acute brain injuries. On the other hand, sustained hypofunctioning of NMDA receptors can result in cognitive dysfunction and is thought to be involved in the pathophysiology of psychosis, Alzheimer’s disease, and autoimmune encephalitis. NMDA receptor antagonists such as phencyclidine Anti-NMDA Receptor Encephalitis: A Need for Increased Awareness Among Psychiatrists