Neurologic Complications of Novel Influenza A (H1N1) Virus Infection from 2009-2011

ABSTRACT

PURPOSE: To describe the characteristics and incidence of neurologic complications related to the novel influenza A (H1N1) virus. METHODS: We reviewed the medical records of 752 children and adolescence (< or = 18 years of age) who had been diagnosed as novel influenza A (H1N1) infection through positive results of influenza A (H1N1) RT-PCR and hospitalized or visited the outpatient clinic and emergency department of Pusan National University Hospital from July 2009 to January 2011. RESULTS: We identified 15 patients who had experienced a neurologic symptom with a mean age of 8.8 years. There were 10 (66.7%) males and five (33.3%) females. Nine patients (60.0%) presented with seizures, two (13.3%) with decreased mentality, two (13.3%) with visual hallucination, and one (6.7%) with vertigo. The mean duration from onset of respiratory illness to the beginning of neurologic symptoms was 2 days (range 0-4 days). Three patients (patient 2, 7, and 13) (20.0%) had abnormal results on cerebrospinal fluid analysis; however, novel influenza A (H1N1) was not detected. Further, one patient (6.7%) had abnormal MRI. Antiviral therapy (oseltamivir) was administered to fourteen patients (93%) and all patients recovered fully and had no neurologic sequelae. CONCLUSION: Novel influenza A (H1N1) was a cause of neurologic symptoms during the outbreak. Pediatricians should consider influenza virus infection in the differential diagnosis for children with neurologic symptoms during an epidemic of influenza.