Summary

Majority of children with pandemic influenza A (H1N1)pdm09 experience mild illness with full recovery without treatment. A previously healthy two and a half month-old girl was admitted to our paediatric intensive care unit because of severe respiratory failure with A (H1N1)pdm09 infection. Despite initial clinical improvement all attempts to extubate to non-invasive ventilation were unsuccessful and 2 to 3 weeks after symptom onset she started periods of cardiovascular instability and a progressive neurological deterioration with distal symmetrical progressive motor weakness and areflexia. All investigations were normal except elevated liver enzymes and cerebrospinal fluid examination that revealed elevated protein without pleocytosis. A possible diagnosis of Guillain–Barré syndrome (GBS) was considered and electromyogram was compatible with axonal form of GBS. To our knowledge this is the youngest case of GBS acquired postnatally and the first in children associated with H1N1 virus.