An autopsy-verified case of steroid-responsive encephalopathy with convulsion and a false-positive result from the real-time quaking-induced conversion assay

Yuichi Hayashi, Yasushi Iwasaki, Nobuaki Yoshikura, Takahiko Asano, Maya Mimuro, Akio Kimura, Katsuya Satoh, Tetsuyuki Kitamoto, Mari Yoshida, Takashi Inuzuka

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We report an autopsy-verified case of steroid-responsive encephalopathy with convulsion and a false-positive result from the real-time quaking-induced conversion (RT-QUIC) assay. A 61-year-old Japanese man presented with acute onset of consciousness disturbance, and convulsions, but without a past medical or family history of progressive dementia, epilepsy, or prion disease. Brain diffusion and fluid-attenuated inverted recovery MR images revealed edematous cortical hyper-intensity, which diminished after the acute phase. Steroid pulse therapy was partially effective, although he continued to have dementia with myoclonus and psychiatric symptoms, despite resolution of the consciousness disturbance. Cerebrospinal fluid (CSF) analysis revealed a normal cell count, with significantly elevated levels of 14–3–3 protein and total tau protein. In addition, prion protein in the CSF was slowly amplified by the RT-QUIC assay. PRNP gene analysis revealed methionine homozygosity at codon 129 without mutation. The patient died of sudden cardiac arrest at 3 months after the onset of symptoms. The positive result from the RT-QUIC assay led us to suspect involvement of prion disease, although a postmortem assessment revealed that he had pathological changes after convulsion, and no prion disease. This case indicates that convulsion may cause false-positive RT-QUIC results, and that a postmortem evaluation remains the gold standard for diagnosing similar cases.

Original languageEnglish
Pages (from-to)284-292
Number of pages9
JournalPrion
Volume11
Issue number4
DOIs
Publication statusPublished - 2017 Jul 4

Keywords

  • 14–3–3 protein
  • MRI
  • anticonvulsant
  • convulsion
  • corticosteroid
  • encephalopathy
  • postmortem study
  • prion disease
  • real-time quaking-induced conversion assay
  • total tau-protein

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience
  • Cell Biology
  • Infectious Diseases

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