Clinical and laboratory parameters associated with febrile seizure recurrence within the first 24 h: a ten-year cohort study

Introduction: We assessed clinical and laboratory parameters associated with early recurrence of febrile seizure in patients presenting at the Emergency Department with a first episode. Methods: Case series of patients admitted to the emergency department with the first episode of febrile seizure for ten consecutive years. Exclusion criteria were focal features and prolonged duration (>15 min). Results: We included 693 patients, 284 (41%) female. Median age of 20 (IQR 15–27) months. Fifty-two (8%) patients had a recurrence within 24 h. At univariate analysis, patients with recurrent seizures had higher use of antipyretics (88% vs. 74%, P = 0.03, OR 2.6, 95% CI: 1.1–7.7), higher median maximal body temperature (39.3 °C, IQR 38.9–39.9, vs. 38.9, IQR 38.4–39.3, P < 0.001, OR 2.3, 95% CI: 1.5–2.6) and presented with a lower proportion of respiratory tract infections (54% vs. 70%, P = 0.02) compared to patients without recurrence. A maximal body temperature equal to or higher than 39 °C was associated with a higher recurrence (11% vs. 4%, P < 0.001, OR 2.9, 95% CI: 1.6–5.6). Hyponatremia was not associated with a risk of recurrence. The multivariate analysis confirmed a direct association with body temperature (OR 2.3, 95% CI: 1.5–3.7, P < 0.001), and an inverse association with respiratory tract infections (OR 0.4, 95% CI: 0.2–0.9, P = 0.01), while antipyretic use was not correlated (OR 1.9, 95% CI: 0.8–5.2, P = 0.2). Conclusions: High body temperature and respiratory tract infections were (directly and inversely) associated with recurrences. Consideration of these conditions might help for anticipating the probability of recurrence.