A long-standing hypothesis holds that prolonged febrile (fever induced) seizures (PFS), the most common form of childhood convulsive status epilepticus (CSE), cause mesial temporal sclerosis (MTS). CSE is a single seizure, or two or more seizures between which consciousness is not regained, lasting for more than 30 minutes. In MTS there is a loss of neurons and scarring of a key brain structure called the hippocampus. Whether prolonged convulsions lead to long-term damage to hippocampus or MTS is uncertain. A team of investigators from the United Kingdom and United States looking into this question has found that a subgroup, and not all, children who experience CSE have impaired hippocampal growth years after the prolonged seizure.
In research reported today at the American Epilepsy Society 67th Annual Meeting, the investigators used three-dimensional, MRI imaging to measure hippocampal volume in 144 children. The cohort included 70 healthy controls and four patient groups based on how the episodes were classified: prolonged febrile seizure, acute symptomatic (CSE at time of causative event such as meningitis, head injury), remote symptomatic (CSE months to years after causative event), and idiopathic/ unclassified. The volumetric images were taken at a mean follow up of 8.5 years (range 6.3-10 yrs.) after the convulsive episode. (Poster 3.182 / abstract 1747929 - Does Childhood Status Epilepticus (CSE) Result in Long-term Hippocampal Damage? A Quantitative Hippocampal Volumetric Analysis.)
The investigators compared the volume of the left and right hippocampus and calculated their asymmetry. They then compared these measures across all groups.