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Reversible splenial lesion associated with novel influenza A (H1N1) viral infection

Aya Iwata1, Kousaku Matsubara, Hiroyuki Nigami

  • 1Department of Pediatrics, Nishi-Kobe Medical Center, 5-7-1 Kojidai, Nishi-Ku, Kobe 651-2273, Japan. lisa-gaspard@hi-net.zaq.ne.jp

Pediatric Neurology
|May 18, 2010
PubMed

Insights

A novel swine-origin influenza A (H1N1) virus caused mild encephalopathy with reversible brain lesions in a 14-year-old boy. Symptoms and brain imaging abnormalities resolved with continued zanamivir treatment.

Area of Science:

  • Neurology
  • Infectious Diseases
  • Radiology

Background:

  • The 2009 pandemic influenza A (H1N1) virus is a novel swine-origin strain.
  • Mild encephalopathy with reversible lesions in the splenium of the corpus callosum (MERS) is a rare neurological complication.
  • The clinical spectrum and neuroimaging findings of MERS associated with H1N1 influenza require further elucidation.

Observation:

  • A 14-year-old Japanese boy presented with dysarthria and dysphagia 5 days after fever onset, during zanamivir treatment for suspected H1N1 influenza.
  • Diffusion-weighted MRI revealed lesions in the splenium of the corpus callosum and bilateral frontoparietal white matter.
  • Neurologic signs included pseudobulbar palsy, without altered consciousness or seizures.

Findings:

  • Continued zanamivir treatment led to complete resolution of neurologic signs within 24 hours.
  • Radiologic abnormalities on MRI resolved within 3 days.
  • This case represents the first reported instance of MERS associated with the novel swine-origin influenza A (H1N1) virus.

Implications:

  • Pandemic 2009 influenza A (H1N1) infection can cause MERS.
  • This finding expands the known clinical spectrum of H1N1-associated neurological complications.
  • Early recognition and continued antiviral treatment may be crucial for favorable outcomes in MERS related to H1N1 influenza.

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