Potential of Early Hippocampal Magnetic Resonance Imaging Findings in Prediction of The Long-Term Consequences of Febrile Status Epilepticus : A Retrospective Study

  • Author / Creator
    Fayzieva, Nozima
  • Background: FSE is a life-threatening condition that puts children at risk of future epilepsy and that requires timely diagnosis and care. FSE can be associated with hippocampal sclerosis and/or development of temporal lobe epilepsy. Not all patients with FSE develop further complications and the specific characteristics of patients in the risk group for developing epilepsy remain unclear. Even though some brain MRI features occurring in the acute phase and over long-term follow-up have been studied in both children and animals, the causal relationships between these findings and risk of adverse seizure outcomes still need clarifying.
    Methods: Patients aged between 1 and 60 months with FSE admitted to the Stollery Children’s hospital PICU from August 2002 to December 2007 were studied. Demographics and long-term seizure outcomes were studied via chart reviews. Brain MRI scans performed within 30 days of FSE were extracted from PACS and reviewed by experienced neuroradiologist, who was blinded to clinical and follow-up data. We evaluated hippocampal T2 signals and presence/absence of hippocampal volume asymmetry in FSE patients. The univariate and multivariate logistic [odds ratio (OR); 95%CI] regressions, and t-tests were used to evaluate the association of MRI findings with further development of epilepsy.
    Results: Out of 309 patients, 54 met the inclusion criteria. The mean age of our FSE patients was 17.19 months (SD=15.22), 30 (56%) subjects were males, median length of seizure was 32.5 minutes (5.0 – 240.0), and patients had a mean body temperature of 38.4 °C (SD=.623). The median interval between admission to PICU and MRI examination was 4 days (0 -30). Fourteen (26%) patients had an early hippocampal T2score ≥ 2, and 23/54 (42%) developed epilepsy in the long term. Of the patients with an early MRI hippocampal T2score ≥ 2, 9/14 developed epilepsy in the long term. Twenty-two (66.7%) of 33 measured patients had hippocampal asymmetry and it made up to 41% (22/54) of all FSE patients, 11/33 (33.3%) patients’ hippocampal volumes were evaluated to be within the ranges of symmetry. Nine (41%) out of 22 patients with hippocampal asymmetry developed subsequent epilepsy (figure 9), 4/11 (36%) of patients without hippocampal asymmetry developed epilepsy.
    The odds ratio of patients with a T2Score ≥ 2 of developing epilepsy was 2.143 [95% CI (0.46, 9.984)], adjusted odds ratio (aOR) was 4.056 [95% CI (0.520 – 31.660)]. The odds ratio of patients with hippocampal volume asymmetry developing epilepsy was equal to 1.35 [95% CI (0.211 – 8.617)], and aOR was 0.838 [95% CI (0.054 - 13.054)].
    Conclusion: This study shows that FSE patients with early T2 signal hyperintensities may have increased odds of developing future epilepsy. MRI done within first 3-7 days would be preferred for more accurate detection and interpretation of imaging findings. Substantial variety in imaging protocols leading to the differences in thickness and number of slices visualizing the hippocampus was a limitation. Dedicated thin section coronal T2 imaging of the hippocampus, which would improve visualization, may increase MRI detection of hippocampus abnormalities in these patients. Systematically accurate coding of diagnoses, recording of exact length of seizure and body temperature immediately after the seizure are crucial.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.