Anti-NMDA Receptor Encephalitis
By Alex Koyfman MD
Edited by Stephen Alerhand MD
Your next 3 patients…
1) 21yo F with change in behavior / depressed consciousness
2) 25yo F with “weird movements” brought in by family
3) 30yo F with AMS + increased muscle tone
Basics
– 1st case described in 2005
– Pathogenesis mediated by antibodies against NR1-NR2 heteromers of the NMDA receptor; unclear precipitating factor
– Patients often brought to the ED by family members 2/2 bizarre behavior
Clinical considerations
– Median age early 20s
– Female predominance
– Initial flu-like illness that progresses over 1-2 weeks => psychosis, AMS, dyskinesias, seizures, autonomic instability
– Other symptoms: increased muscle tone, new psychiatric symptoms (agitation, hallucinations, sleep disturbance, paranoia), AMS, memory problem, movement disorder (dyskinesias), autonomic instability, seizure
– think limbic encephalitis (affects hippocampus and limbic system)
Differential diagnosis
– Encephalitis, brain mass, endocrine emergency, NMS, serotonin syndrome, Psych, ketamine / PCP intoxication; when considering these, add anti-NMADR encephalitis to your list
– About 60% found to have cancer (paraneoplastic), most commonly ovarian teratoma
Diagnosis
– CSF and serum sent for antibodies
Treatment
– Supportive care
– High-dose steroids / IVIG / plasma exchange
– Cancer surgery PRN (the earlier the better)
Prognosis
– About 75% cured with no / mild deficit(s)
– 7% mortality
Examples of Treatment Algorithms
(Kruse, Jennifer L. et al. Anti-N-methyl-d-aspartate receptor encephalitis: A targeted review of clinical presentation, diagnosis, and approaches to psychopharmacological management. American Academy of Clinical Psychiatrists, Feb 2014.)
(Li, L. Wang, CB. Zaho, G. Anti-N-methyl-D-aspartate- receptor encephalitis in China. Neuroimmunology and Inflammation, June 2014)
Further Reading
– http://www.ncbi.nlm.nih.gov/pubmed/18851928
– http://www.ncbi.nlm.nih.gov/pubmed/25413552
– http://www.ncbi.nlm.nih.gov/pubmed/24211006
– http://www.ncbi.nlm.nih.gov/pubmed/24355654
– http://emergencymedicinecases.com/best-case-ever-28-david-carr-anti-nmda-receptor-encephalitis/
– http://www.emrap.org/episode/2014/june/nmda (see Comments section for enlightening cases)
– http://www.susannahcahalan.com/ (patient’s view)
