[Differential diagnosis in children having delirium associated with high fever]

Children who present delirium associated with high fever may develop with encephalitis or encephalopathy, especially in influenza infection. The aim of this study is to differentiate the patients with the central nervous infection or with the parasomnias from benign transient delirium in patients who visit the emergency room complaining of illusions. Ten patients aged from 2 to 7 years were enrolled in this study. There were 2 patients with central nervous infection, one with encephalo-myelitis due to mycoplasma infection and one with acute necrotizing encephalopathy due to influenza infection. The remaining 8 patients had benign delirium associated with high fever which disappeared in a self-limiting manner. Three patients had a febrile seizure (FS) and 4 patients had family history of FS. The points to differentiate the delirium with parasomnias from benign type is fearful expression, positive past history, autonomic nerve symptoms. Delirium consisted of visual hallucination, and occurred in association with sleep except in the patients with encephalopathy who became delirious when they were awake. Abnormal neurological findings such as meningeal signs and disturbed consciousness, appearance of delirium in the waking state, and marked slowing in the EEG background activity were considered to be warning factors useful in differentiating the benign type from the delirium with central nervous infection.