| Summary: | Convulsive Status Epilepticus (CSE) is the most common medical neurological emergency in children. Prolonged seizures are associated with brain injury in both animal models and humans and there is concern about longer term outcomes. A qualitative difference between prolonged and shorter seizures is apparent, but information about the longer term prognosis of CSE remains scarce. Retrospective studies have linked the commonest form of childhood CSE, prolonged febrile seizures (PFS), and temporal lobe epilepsy due to mesial temporal sclerosis (TLE-MTS). This study aimed to prospectively follow a population-representative cohort of children following CSE and look for signs of evolving MTS or other brain injury. Magnetic resonance imaging (MRI) was used to visualise underlying brain abnormalities and identify early signs of injury. To investigate the longitudinal evolution of any injury, MRI investigations were repeated at 6 and 12 months post-CSE and the child’s clinical status monitored throughout. 31.2% of children had an abnormal MRI scan post-CSE. Most of these abnormalities pre-dated the episode of CSE and no clinically significant abnormalities were found in children with PFS. Mean hippocampal volumes were only reduced in the group of children with symptomatic CSE; however 20-30% of all children showed loss of hippocampal volume during the year following CSE. This could represent a precursor to TLE-MTS. Further abnormalities were shown on diffusion tensor imaging in children with PFS. Hippocampal mean diffusivity did not show the usual age dependency and widespread reductions in fractional anisotropy were seen across major white matter tracts. These reductions were apparent at 1 and 6 months post-PFS, but resolved by 1 year. These findings form important evidence that children with non-PFS CSE are also at risk of long-term hippocampal damage and that children with PFS appear to have extensive extra-hippocampal abnormalities. These will be further explored in the body of this thesis.
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