Pediatric anti‐NMDA receptor encephalitis is seasonal

Abstract

In the majority of pediatric anti-N-methyl-d-aspartate receptor encephalitis (NMDARe) cases, the underlying cause of antibody production and subsequent disease remains unknown. We aimed to characterize this poorly understood population, investigating epidemiological factors potentially related to disease etiology, particularly season of onset. In this retrospective case review study, we analyzed data from the 29 pediatric subjects with anti-NMDAR antibodies and found that symptoms were first reported in the warm months of April–September in 78% of non-tumor-related NMDARe (NT-NMDARe) cases. These findings support further investigation into a possible seasonal trigger of NT-NMDARe.

First Bahraini adolescent with anti-NMDAR-Ab encephalitis

“… 6 A possible seasonal trigger was hypothesized for non-tumor NMDAR encephalitis, as a subset of studied patients without tumors had their onset of symptoms primarily in warm months. 11 …”

“…Finally, a direct effect of the antibodies on the nucleus of the Kölliker-Fuse or the pontomedullary respiratory network could explain the respiratory dysfunction. 11 …”

Anti-AMPA receptor encephalitis

“…Recently, pediatric non-tumor-associated anti-NMDAR encephalitis was reported as seasonal, suggesting that other infections besides HSV may play a similar role. 11 Further complicating the picture are the varied pathologic features of autoimmune encephalitides, which differ according to the associated autoantibody, with some appearing more reversible than others both in vitro and in patients. 7,12 Finally, therapeutic requirements may differ among syndromes; for example, there is clearly a role for rituximab in anti-NMDAR encephalitis, 2 whereas in anti-LGI1 encephalitis steroids remain the mainstay of treatment.…”

Klinik und Immunpathogenese der Anti-NMDAR-Enzephalitis und anderer Autoimmun-Enzephalitiden

“…Von 29 Kindern hatten 6 einen Tumor, diese erkrankten in der Winterzeit (Oktober-März). Im Gegensatz dazu kam es bei Kindern ohne Tumor überwiegend in den warmen Monaten des Jahres (April-September) zu einer NMDAR-Enzephalitis [10]. Die Ursache dieses saisonalen Triggerfaktors ist (wie bei anderen Autoimmunerkrankungen) bisher unbekannt.…”