Anti-NMDA receptor encephalitis

Anti-NMDA receptor encephalitis is a type of brain inflammation due to antibodies.

Early symptoms may include fever, headache, and feeling tired.

This is then typically followed by psychosis which presents with false beliefs (delusions) and seeing or hearing things that others do not see or hear (hallucinations).

People are also often agitated or confused.

Over time seizures, decreased breathing, and blood pressure and heart rate variability typically occur.

About half of cases are associated with tumors, most commonly teratomas of the ovaries, while the cause in others cases is unclear.

The underlying mechanism is autoimmune with the primary target the GluN1 subunit of the N-methyl D-aspartate receptors (NMDAR) in the brain.

Diagnosis is typically based on finding specific antibodies in the cerebral spinal fluid.

MRI of the brain is often normal.

Misdiagnosis is common.

Treatment is typically with immunosuppresive medication and, if a tumor is present, surgery to remove it.

With treatment about 80% of people have a good outcome.

Outcomes are better if treatment is begun earlier.

Long term mental or behavioral problems may remain.

About 4% of those affected die from the condition.

Reoccurrence occurs in about 10% of people.

The condition is relatively common.

About 80% of those affected are female.

It typically occurs in adults less than 45 years old but can occur at any age.

The disease was first described by Josep Dalmau in 2007.

Jeannin-Mayer S, André-Obadia N, Rosenberg S, Boutet C, Honnorat J, Antoine JC, Mazzola L. EEG analysis in anti-NMDA receptor encephalitis: Description of typical patterns. Clin Neurophysiol. 2018 Nov 29;130(2):289-296. doi: 10.1016/j.clinph.2018.10.017. [Epub ahead of print] PubMed PMID: 30611120.

A 24-year-old woman with a subacute onset of psychotic and catatonic symptoms in whom current diagnostic criteria for probable anti-NMDAr encephalitis were not fulfilled. On the basis of the red flags that have been proposed to raise suspicion of anti-NMDAr encephalitis, a study of fluorodeoxyglucose positron emission tomography was requested and demonstrated bilateral occipital hypometabolism consistent with clinical suspicion of anti-NMDAr encephalitis. Once the appropriate treatment was established, the patient recovered completely. This case supports the need to maintain clinical suspicion of anti-NMDAr encephalitis, even when conventional diagnostic tests have been normal. Psychiatrists should be familiar with this entity to promote timely diagnosis and prompt treatment ¹⁾.