Introduction
Anti-N-methyl-d-aspartate (Anti-NMDA) encephalitis (ANMDARE), an autoimmune initially manifests as viral prodrome progressing to psychiatric symptoms. These lead to movement disorders and/or seizures ultimately progressing to decreased level of consciousness. The extreme delta brush is a pattern usually observed in frontotemporal regions of premature infants. This pattern normally goes off upon anti-epileptic treatment, but it can last for months in certain situations, however, it is observed in anti-NMDAR encephalitis.
Objective
To evaluate the role of the extreme delta brush as a prognostic factor for ANMDARE.
Study Design
A systematic review using Meta-analyses Of Observational Studies in Epidemiology (MOOSE) protocol.
Methods
Eight observational human studies including patients with NMDARE were considered for review. .
Results
- Seizures were present in 178/249 (71.48%) patients. Status Epilepticus was reported in 29/96 (30.20%) patients that suffered from seizures.
- In the pooled data, extreme delta brush was found in 30.89% (55/178) patients with seizures. The array of extreme delta brush was 5.9%-33% among the studies.
- Overall, extreme delta brush was linked to a longer hospital stay, more ICU admissions, and a higher rate of status epilepticus.
- The cause of the extreme delta brush was largely unknown. However, it has been suggested that in NMDAR encephalitis, rhythmic neuronal activity is disrupted due to bloackage of NMDAR by antibodies .
- Antibodies that block/target the NMDAR impair rhythmic neural activity, resulting in the distinctive extreme delta brush pattern. The superimposition of the beta waves is linked to NMDA receptor changes, whereas delta activity is induced by focal abnormalities in the brain.
Conclusion
The presence of extreme delta brush pattern may be a sign of more severe disease and worse short-term outcomes, but it has no effect on long-term outcomes. TPE treatment can improve short-term clinical outcomes, including epilepsy, in severe anti-NMDAR encephalitis, suggesting that patients with an extreme delta brush pattern could benefit from it.