[Usefulness of EEG recording for delirium in children with high fever].

Delirium in children associated with high fever is defined as an acute and transient confusional state. Clinically it is most important to differentiate delirium from encephalitis or encephalopathy. Electroencephalographic (EEG) tracings were obtained from 17 children with fever and delirium, consisting of 12 boys and 5 girls, aged from 2 to 13 years. The initial recording was done from 2 to 36 hours (mean: 15 hours) after the last episode of delirium. The causes of fever were upper respiratory infections in 14 patients, acute bronchitis in 1, measles in 1 and exanthema subitum in 1. The body temperature ranged from 38.0 to 41.0 degrees C, when delirium was noticed by their parents. On 15 EEG tracings obtained during waking, the alpha rhythm showed a frequency normal for age, but it was interrupted by posterior slow waves in 2 of them. Eight tracings showed abnormal occipital delta activities. These slow waves were blocked by eye opening, and disappeared within 1 to 5 days. Two of the 6 tracings during sleep showed high voltage irregular slow wave bursts mixed with spikes lasting for 7 minutes, which also disappeared within 1 to 2 days. Our results indicate that EEG is useful in differentiating delirium from encephalitis or encephalopathy; in delirium, the occipital delta waves are blocked by eye opening and abnormal activities disappear within a few days.