Abstracts

Rationale: There are scarce data on the clinical characteristics of children with recurrent convulsive status epilepticus (CSE). The aims of this study are to describe the clinical features of children with recurrent episodes of CSE and to compare them with those of patients with a single episode of CSE.Methods: We performed a retrospective observational study and included consecutive patients with 1) at least three episodes of CSE (defined as seizure duration of at least 30 minutes), 2) during the period 2005-2010, and 3) an age of 1 month to 21 years at the time of the first episode of CSE. We age-matched every patient with a control (patients with a single episode of CSE during the same period).Results: We identified 23 patients (12 males) with at least three episodes of CSE [including 13 patients (7 males) with 3 episodes, 4 (1 male) with 4 episodes, 4 (2 males) with 5 episodes, 1 (1 male) with 7 episodes, and 1 (1 male) with 11 episodes]. All 23 controls (12 males) had only one episode of CSE during the same time period. The median (p25-p75) age at the first seizure was 0.5 (0.08-2.25) years for cases and 0.7 (0.3-2.5) years for controls, and these ages were not significantly different (Wilcoxon rank sum test z=0.935, p=0.35). The median (p25-p75) duration of the first episode of CSE was 45 (40-90) minutes in cases, and 50 (40-60) minutes in controls (Wilcoxon rank-sum test z= 0.467, p= 0.64). We could not find differences between the two groups with regards to seizure semiology, seizure frequency, number of prescribed anti-epileptic drugs and presence of developmental delay at baseline (all with p>0.1). A focal abnormality on baseline EEG was more frequent in cases (Fisher s exact test, p=0.057). There was no difference in MRI abnormalities between cases and controls; 9 controls and 12 cases had MRIs prior to the first episode and the same proportion of patients, 6 controls (66.7%) and 8 cases (66.7%), had abnormal findings (Fisher s exact test, p>0.99). The median (p25-p75) time to a second episode of status epilepticus after the first episode was 155 (29-568) days (Figure 1A) with earlier recurrence in females as compared to males (logrank test chi-square= 6.76, p= 0.01) (Figure 1B), but no differences between patients with and without developmental delay (logrank test chi-square= 0.12, p= 0.73) (Figure 1C), and patients with and without an abnormal MRI (logrank test chi-square= 0.00, p= 0.98) (Figure 1D). The median (p25-p75) time interval to a third episode of status epilepticus after the second episode was 182 (62-510) days (Figure 2A). The median (p25-p75) time interval to a fourth episode of status epilepticus after the third episode was 68 (5-198) days (Figure 2B). Conclusions: We identified focal abnormalities on baseline EEG as a risk factor for recurrence of SE. The timing of recurrent SE (second episode of CSE) was significantly delayed in males, but the presence of developmental delay at baseline and abnormal baseline MRI had no influence on the timing of CSE recurrence.