Transient and mild reduction of consciousness during febrile illness in children.

We have studied the clinical and neuroimaging characteristics of transient and mild reduction of consciousness during febrile illness in children. We retrospectively evaluated 58 children admitted with mild reduction of consciousness within 12 h during febrile illness. 53 patients (91%) had delirious behavior, and 5 (9%) had no delirious behavior. We also compared the clinical characteristics, brain magnetic resonance imaging (MRI) findings, and electroencephalography (EEG) findings between patients with and without delirious behavior, and no statistically significant differences were observed in any of them between the 2 patient groups (P≥0.05). MRI was performed 0-4 days after onset in 23 patients. Reversible splenial or callosal and white matter lesions were observed in 2 of 3 patients without delirious behavior vs. 4 of 20 patients with delirious behavior on diffusion-weighted images. EEG was performed 0-3 days after onset in 29 patients. Transient abnormal findings were observed in 3 of 4 patients without delirious behavior vs. 11 of 25 patients with delirious behavior. In conclusion, we consider that transient and mild reduction of consciousness during febrile illness is a unique clinical group that is constituted by children both with and without delirious behavior.