Dr. David Carr presents his second of Carr’s Cases. This series features some potentially life-threatening diagnoses that may be perceived as zebras, but actually have a higher incidence then we might think – and if diagnosed early, can significantly effect patient outcomes.  This Best Case Ever is about Anti-NMDA Receptor Encephalitis, a diagnosis that was only discovered in 2005, and has only recently been recognized by the Emergency Medicine community.  Anti-NMDA Receptor Encephalitis may mimic a first presentation of schizophrenia or Neuraleptic Malignant Syndrome.  It may present with seizure, altered mental status, autonomic instability or movement disorder in the absence of drug exposure. When you are faced with any of these presentations and no other diagnosis seems to fit, do an LP and send the CSF for anti-NMDA receptor antibodies. The time-sensitive treatment is IVIG and steroids.  Anti-NMDA receptor Encephalitis is a must know diagnosis for all emergency medicine practitioners.  Learn how to pick up this important diagnosis by listening to Dr. Carr’s Best Case Ever and following the links to further resources.

Published Aug, 2014 by Anton Helman

Dr. Carr’s prepublication article in CJEM on Anti-NMDA Receptor Encephalitis Full Text

Suzanna Callahan describes her experience of Anti-NMDA Receptor Encephalitis in her book, Brain on Fire

Concise review by Chris Nickson with more references on Life in the Fast Lane

Take Home Points

  • predominantly a disease of young women (mean age = 21) with 7% mortality rate
  • associated with pelvic teratoma tumors
  • Four clinical phases: 1. flu-like prodrome 2. psychotic phase 3. altered mental status and dyskenesia  4. autonomic instability and seizures
  • can mimic first episode psychotic disorder, NMS and Seratonin Syndrome
  • diagnosis by LP with CSF positive for anti-NMDA receptor antibodies
  • time to initiation of therapy with IVIG and steroids is best predictor of outcome

Check out this video showing the characteristic movement and behaviour of a patient with Anti-NMDA Receptor Encephalitis.

Key Reference

Young PJ, et al. A case series of critically ill patients with anti- N-methyl-D-aspartate receptor encephalitis. Crit Care Resusc. 2013 Mar;15(1):8-14.

Dr. Helman and Dr. Carr of no conflicts of interest to declare.