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A new infectious encephalopathy syndrome, clinically mild encephalopathy associated with excitotoxicity (MEEX)

Nozomi Hirai1, Daisuke Yoshimaru2, Yoko Moriyama1

  • 1Department of Pediatrics, Tokyo Women's Medical University, Yachiyo Medical Center, Yachiyo, Japan.

Journal of the Neurological Sciences
|September 6, 2017
PubMed

Insights

A new encephalopathy syndrome, mild encephalopathy associated with excitotoxicity (MEEX), is identified in children. This condition, characterized by elevated brain glutamine, suggests excitotoxicity as a common mechanism in acute infectious encephalopathy.

Area of Science:

  • Pediatric Neurology
  • Neuroscience
  • Metabolic Disorders

Background:

  • Acute infectious encephalopathy is prevalent in East Asian children, with over 40% remaining unclassified.
  • Identifying specific syndromes and underlying mechanisms is crucial for effective treatment.

Purpose of the Study:

  • To investigate the pathomechanisms of unclassified encephalopathy in children using MR spectroscopy.
  • To propose a new encephalopathy syndrome based on metabolic findings and clinical presentation.

Main Methods:

  • MR spectroscopy was used to evaluate brain metabolism in seven pediatric patients with acute encephalopathy.
  • Patients were classified into known syndromes or diagnosed with unclassified encephalopathy based on clinical and imaging findings.

Main Results:

  • Four patients with unclassified encephalopathy showed increased brain glutamine and normal N-acetyl aspartate on MR spectroscopy during the acute phase.
  • These metabolic abnormalities normalized upon clinical recovery.
  • The proposed new syndrome, mild encephalopathy with excitotoxicity (MEEX), accounted for 26% of encephalopathy cases, second only to acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) at 30%.

Conclusions:

  • Excitotoxicity is suggested as a common pathomechanism in acute infectious encephalopathy.
  • MEEX represents a distinct clinical entity within acute infectious encephalopathy.
  • Early astrocytic neuroprotection may prevent MEEX progression to more severe forms like AESD.
Keywords:
Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD)Clinically mild encephalopathy associated with excitotoxicity (MEEX)EncephalopathyExcitotoxicityGlutamateGlutamineMR spectroscopy

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