Severe Encephalopathy With Swine Origin Influenza a H1n1 Infection in Childhood: Case Reports

The potential for severe respiratory complications associated with swine origin influenza A H1N1 is well documented.1 Australia has seen a dramatic increase in the number of cases of H1N1 infection. H1N1 currently is responsible for >50% of all influenza cases in the Australian 2009 winter. Recently 4 children were reported with neurologic complications associated with swine origin influenza A H1N1.2 We report 2 previously well children who presented to our institution over a 2-week period with serious neurologic complications and focal changes on MRI associated with H1N1 2009 influenza infection. ### Case reports. Case 1 was a previously healthy 5-year-old girl who presented with 3 days of fever, right occipital headache, confusion, and drowsiness. She was febrile (38.5°C), agitated, and had a left hemiplegia. A brain MRI showed high signal and swelling of the right parieto-occipital cortex on T2-weighted images with diffusion restriction in the underlying subcortical white matter (figure, A). A nasopharyngeal swab specimen was positive for influenza A by direct immunofluorescence (IF), which was identified as influenza H1N1 of swine origin by real-time PCR.3 CSF RT-PCR was negative for H1N1 influenza virus. Treatment was started with oseltamivir within 24 hours of admission. She subsequently developed focal status epilepticus (clonic jerking of left hand and face) with right posterior spike and wave activity on EEG. …