A 19 y.o. presents with seizures
You notice bizarre Delta waves on her EEG. What could be wrong?
Hint: it has something to do with the molecule below.
Our patient had NMDA receptor encephalitis with antibodies found in her CSF. NMDA receptor encephalitis is a type of brain inflammation caused by antibodies to synaptic neural elements. Because it affects the temporal and frontal lobes it can cause symptoms similar to schizophrenia with paranoia and delusions. Seizures are also common.
Since its discovery in 2005, many cases of NMDA (N methyl D aspartate) receptor antibody encephalitis have been reported. It was initially reported in women with ovarian teratomas but it was also found in patients without malignancy. It can present as seizures, psychosis, memory defects and languange disintegration.
Teratomas are a type of germ cell tumor occuring in the testes or ovaries. In large series they account for 85% of NMDA receptor antibody encephalitis.
Neural antibody associated encephalitis has been reported after vaccination for influenza and MMR. It can also be triggered by herpes virus. The disease occurs on a spectrum with the most severe cases causing coma and a 3-4 month hospitalization, while other patients have only personality changes. While NMDA is the most common neural receptor associated with encephalitis, GABA-R (gamma –aminobutyric acid-B receptors ,AMPAR( isoxazolepropionic acid receptors) and LGH (leucine-rich glioma-inactivated 1) receptor antibodies also cause encephalitis. In these cases limbic areas of the brain; the hippocampus and amygdala, produse abnormalities of emotion and memory.
. Brain MRI is unremarkable in 50% of patients, however, EEGs are abnormal in most patients.
Our patient did not have a teratoma or any of the other reported tumors associated with NMDA receptor antibody encephalitis (lung,uterine, prostate, hodgkins, neuroblastoma or pancreatic),. She was treated with 5g of methyl pred and discharged on Vimpat 100 bid with kepprea 1500 bid. She was also discharged on a prednisone taper over two weeks.
Gillinder L, Warren N, Hartel G, et al. EEG findings in NMDA encephalitis-a systematic review. Seizure 2019 Vol 65: 20-24.
Dalmau J, Gleichman A, Hughes E, et al. Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies. Lancet neurol 2008;7:1091-98.
Spatola M, Petit-Pedrol M, Simabukura M, et al. Investigations in GABAA receptor antibody-associated encephalitis Neurology 88(11) :1012-1020.
Alzghoul H, Kadri F, Ismail M, et al. Paraneoplastic NMDA encephalitis, a case report and an extensive review of available literature Radiology Case Reports Vol 19 (4):1371-1385.
https://doi.org/10.1148/rg.220173