Objective: To analyze the spectrum of neurological manifestations in children hospitalized with pandemic influenza A H1N1 virus of 2009 (pH1N1).
Design: Retrospective case series of children hospitalized from May 1, 2009, through November 30, 2009.
Setting: Tertiary-care children's hospital in Colorado.
Patients: All hospitalized patients with pH1N1 with neurological consult or diagnosis, lumbar puncture, electroencephalogram, or neuroimaging were selected as suspected cases. These were systematically reviewed and selected for final analysis if confirmed by pre-established definitions as a neurological complication.
Results: Of 307 children with pH1N1, 59 were selected as having suspected cases of neurological complications. Twenty-three children were confirmed to have a neurological complication. Of these 23, 15 (65%) required intensive care monitoring. The median length of stay was 4 days. Seventeen (74%) had a preexisting neurological diagnosis. The most common manifestation was seizure with underlying neurological disease (in 62% of cases) followed by encephalopathy with or without neuroimaging changes (in 26% of cases). Results from a lumbar puncture showed elevated protein levels in 3 of 6 patients but no significant pleocytosis. Seven of the 9 electroencephalograms showed diffuse slowing, and findings from magnetic resonance imaging were abnormal in 5 of 6 children. Deaths occurred in 13% of patients, and short-term disability in 22%.
Conclusions: Children infected with pH1N1 presented with a wide spectrum of neurological manifestations, which occurred primarily in individuals with preexisting neurological conditions. These individuals had a severe disease course, evidenced by need for intensive care services and relatively high rates of mortality or neurological disability. Children with underlying neurological conditions should be particularly targeted for influenza prevention and aggressive supportive treatment at the onset of influenzalike symptoms.