J Korean Med Sci.  2012 Apr;27(4):402-407. 10.3346/jkms.2012.27.4.402.

Neurologic Complications and Outcomes of Pandemic (H1N1) 2009 in Korean Children

• Kwon S
• Kim S
• Cho MH
• Seo H

• KMID: 2157901
• DOI: http://doi.org/10.3346/jkms.2012.27.4.402

Abstract

Neurologic complications of children with influenza A H1N1 2009 pandemic, diagnosed in two consecutive influenza seasons were retrospectively reviewed to seek better outcomes in future outbreaks. Patient demographics, clinical manifestations and neurologic outcomes were reviewed. A total of 1,389 children were diagnosed with influenza A H1N1 by real-time reverse transcriptase-polymerase chain reaction. Of these, 23 (1.7%) patients had neurologic involvement. Their mean age was 5.9 +/- 3.6 yr (range, 6 months to 11 yr) and 16 (69.9%) were boys. None of the 23 patients had been vaccinated for influenza A H1N1 and seasonal influenzas. Twenty-two of the 23 patients presented with seizures. Clinical features included febrile convulsion (n = 19), afebrile convulsion (n = 1), aseptic meningitis (n = 1), encephalopathy (n = 1), and acute necrotizing encephalopathy (n = 1). They all were treated with Oseltamivir twice daily for 5 days immediately after nasal and throat swab testing. Twenty-one of the subjects recovered fully, but the youngest two infants experienced severe neurological sequelae. The results indicate that neurologic complications associated with influenza A H1N1 2009 pandemic were mostly mild, but rarely were serious. Prompt intervention leads to a better outcome and vaccination may prevent the disease, thus staving off serious neurological complications following influenza, especially in young infants.

Keyword

Influenza A H1N1; Neurologic Complication; Prognosis; Child

MeSH Terms

Antiviral Agents/therapeutic use
Child
Child, Preschool
Electroencephalography
Female
Humans
Infant
Influenza A Virus, H1N1 Subtype/*genetics
Influenza, Human/*complications/drug therapy/*epidemiology
Magnetic Resonance Imaging
Male
Oseltamivir/therapeutic use
Pandemics
Republic of Korea/epidemiology
Retrospective Studies
Seizures/*etiology

Figure

• 

  Fig. 1 Incidence and percentage of influenza A H1N1 PCR and neurologic complications. During the 2009-2010 influenza season, 3,019 children were PCR-tested for influenza A H1N1. Of these, 1,326 (43.9%) were positive and 20 patients (1.5%) had neurologic complications. From September 2010 to March 2011, 63 patients (15.7%) were positive among 402 children and three patients (4.7%) experienced neurologic complications. A total of 1,389 children were confirmed with influenza A H1N1; 23 (1.7%) of them had neurological involvement.

• 

  Fig. 2 Brain MRI of the patient with acute necrotizing encephalopathy. (A) Initial T2-weighted image shows a high signal intensity lesion (arrows) in both thalami. (B) Follow-up brain MRI reveals bilateral symmetric hyperintense lesions (arrows) in the both thalami on T2-weighted image.

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