Twenty-four-hour pattern of children with febrile seizures presenting to a United States Pediatric Emergency Department

Background: Febrile seizure (FS) is the most common convulsive disorder in children. Understanding its time-of-day pattern can provide insight into mechanisms and prevention. Purpose: We explored clock-time variation of FS presentations of children to a US pediatric emergency department (PED) in comparison to two control cohorts: one (n = 5719) like-aged children presenting solely with fever, i.e., temperature > 100.4 degrees F/38 degrees C, and one of children (n = 103,806) presenting for any medical emergency. Methods: Electronic medical records covering a 58-month span were searched for clock time of arrivals to the PED, with data assessed either by chi-square or Cosinor analyses to test for temporal variation and derive descriptive parameters. Major findings: Presentation of the 84 FS cases exhibited a time-of-day difference (p = .038), being 5-fold higher between 16:00-19:59 h than 08:00-11:59 h. Presentations of both control groups additionally exhibited such difference, with peak numbers between 16:00 and 19:59 h. Fever intensity of cases tended to be greater by 0.58 degrees F (p > .10) in those attending the PED between 16:00-23:59 h than 00:00-07:59 h. The control group of children solely with fever showed (p < .0001) time-of-day variation in body temperature, with the difference between presentations of highest and lowest temperature, respectively at similar to 21:40 and similar to 09:40 h, of 0.4 degrees F. Novelty of findings: This is the first study to report time-of-day variation in FS of American children, which is like that reported in children of other countries. The peak number of presentations for FS corresponds in time both with that for fever without seizure and that for any medical emergency, and, additionally, fever intensity of fever controls.