Late relapse of anti-N-methyl-d-aspartate receptor encephalitis with amusia and transiently reduced uptake in 123I-iomazenil single-photon emission computed tomography.

Abstract

INTRODUCTION:

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis has a high relapse rate at approximately 10-20%. Most relapses occur within 2 years from onset, and 5 years after onset is rare. We report a case of anti-NMDAR encephalitis relapse with amusia 10 years after the initial encephalitis and discuss the usefulness of 123I-iomazenil single-photon emission computerized tomography (IMZ-SPECT) for its diagnosis.

CASE:

A 13-year-old left-handed girl presented with a depressed level of consciousness and focal to bilateral tonic-clonic seizures. Cerebrospinal fluid (CSF) analysis showed a mildly increased white blood cell count, elevated neopterin levels, and positive oligoclonal bands. Brain MRI was normal. IMZ-SPECT revealed reduced uptake in the right frontoparietal region. She received intravenous pulse methylprednisolone (IVMP) and high-dose intravenous immunoglobulin for autoimmune encephalitis; her symptoms resolved without neurological deficits. At 23 years old, she had mild right-sided numbness, dysarthria, amusia, and tonic-clonic seizures. Although the CSF analysis and brain MRI were normal, IMZ-SPECT revealed reduced uptake, indicating a relapse of encephalitis. IVMP administration resolved the symptoms. After discharge, the initial and relapse CSF analysis revealed anti-NMDAR antibodies.

CONCLUSION:

An anti-NMDAR encephalitis relapse 10 years after onset has never been reported. IMZ-SPECT may help in the diagnosis of anti-NMDAR encephalitis.

• Authors: Naoki Yamada, Ichiro Kuki, Taeka Hattori, Naohiro Yamamoto, Shizuka Nagase, Megumi Nukui, Takeshi Inoue, Shin Okazaki, Hisashi Kawawaki, Asako Horino, Hiroshi Sakuma
• Journal: Brain & development (Brain Dev) Vol. 44 Issue 8 Pg. 558-561 (Sep 2022) ISSN: 1872-7131 [Electronic] Netherlands
• PMID: 35662527 (Publication Type: Case Reports)
• Copyright: Copyright © 2022 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Chemical References

• Iodine Radioisotopes
• Receptors, N-Methyl-D-Aspartate
• Flumazenil
• iomazenil
• Iodine-123

Topics

• Adolescent
• Adult
• Anti-N-Methyl-D-Aspartate Receptor Encephalitis (complications, diagnostic imaging)
• Female
• Flumazenil (analogs & derivatives)
• Humans
• Iodine Radioisotopes
• Neoplasm Recurrence, Local
• Receptors, N-Methyl-D-Aspartate
• Seizures
• Tomography, Emission-Computed, Single-Photon
• Young Adult