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

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.

Recurrent Plastic Bronchitis in a Child with 2009 Influenza A (H1N1) and Influenza B Virus Infection

“…Kwon et al (18) reported that none of children with severe neurologic complication from H1N1 in his study had been immunized for H1N1 and seasonal influenzas.…”

Outbreak of Influenza B related to Benign Acute Childhood Myositis

“…Influenza infection presents with various complications, such as pneumonia and otitis media in children, but it seldom causes neurologic complications. One investigation indicated that influenza A (H1N1) pdm09 caused neurologic involvement in 1.7% of infected patients, of whom 67% had seizures; most patients with neurologic involvement showed mild neurologic symptoms, with a good prognosis observed for Korean children 2) . Several studies have reported that BACM is associated with influenza infection, particularly infection with influenza subtype B 13,14) .…”

“…Influenza can also cause pneumonia, which often requires hospitalization. Neurologic complications can also result from influenza virus infection; Asian children are particularly vulnerable to such complications 1,2) . These complications range from mild to severe and can be fatal.…”

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

“…Seizure has been reported as the most common neurologic complication of seasonal influenza A and B (6,17), as well as pandemic (H1N1) 2009 (8,18), but shows good prognosis. In contrast, encephalopathy is rare, but it can cause a serious outcome, especially in patients of young age or with underlying neuromuscular disorder (6).…”

“…Compared with seasonal influenza, H1N1 is not more severe, but neurologic complications such as encephalopathy, focal neurologic sign, aphasia and abnormal electroencephalogram findings can be more common (11,20). Neurologic complications resulting from H1N1 in pediatric populations include various clinical manifestations such as seizure, aseptic meningitis, encephalitis and acute disseminated encephalomyelitis and can result in significant acute and residual neurologic sequelae (14,18). During influenza season, pediatricians should consider influenza as the cause of unexplained mental status change, especially in a patient with an underlying chronic illness, because of more aggressive clinical course.…”