Peripheral leukocytosis in children with febrile seizures.

Peripheral blood leukocytosis has been reported following febrile seizures as a result of infection, the seizure, or both. To examine this relationship, 238 consecutive children < 5 years of age who experienced their first febrile seizure were evaluated. Lumbar punctures were electively done on 128 of the children to rule out central nervous system infection. Total leukocyte counts and duration of fever before the seizure were negatively correlated (r = - .175, P < .05). In logistic regression analysis, the logarithm of fever duration before the seizure was negatively associated with leukocytosis (leukocyte count > or = 15,000 cells/microL [odds ratio: 0.117, P < .05]). Cerebrospinal fluid glucose concentrations were significantly correlated with increased body temperature (r = .230, P < .05) and increased leukocyte counts (r = .255, P < .01). No significant association was found between leukocyte counts and the characteristics of the febrile seizure event. By all indications, changes in leukocyte counts appear more likely to be related to the length and underlying etiology of the fever than to the seizure itself.