Hyperpolarization and short-circuiting as mechanisms of seizure prevention following febrile convulsions
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E J Aiyathurai1, P S Low, E Jacob
1Department of Paediatrics, National University Hospital, Kent Ridge, Singapore.
Insights
Febrile convulsions in children are linked to fever, but later stages show adaptive hyperglycemia. This hyperglycemia helps restore neuronal function by regulating potassium and chloride levels, preventing further seizures.
Area of Science:
- Pediatric Neurology
- Neurochemistry
- Metabolic Disorders
Background:
- Febrile convulsions in children are commonly attributed to fever.
- Seizures typically occur early in febrile illness, with later stages less understood.
- The role of metabolic and electrolyte changes in preventing seizure recurrence is unclear.
Purpose of the Study:
- To investigate serum electrolyte and metabolite profiles in the later stage of febrile convulsions.
- To identify potential fuel responses and electrophysiological changes that may prevent further seizure activity.
- To understand the adaptive mechanisms during recovery from febrile convulsions.
Main Methods:
- Analysis of serum electrolyte and metabolite profiles during the later stage of febrile illness.
- Assessment of intracellular glucose starvation markers (ketones, lactate).
- Evaluation of electrolyte pump function (hyperuricemia, Na+, Cl-, Ca2+, K+).
Main Results:
- Intracellular glucose starvation was observed, indicated by increased ketones and lactate.
- Evidence of electrolyte pump dysfunction (hyperuricemia, decreased Na+, Cl-, Ca2+).
- Adaptive hyperglycemia and decreased serum K+ were noted, alongside Cl- influx.
Conclusions:
- Hyperglycemia likely induced K+ uptake by neurons, promoting repolarization and preventing seizures.
- Chloride influx may have counteracted depolarizing currents, further inhibiting seizure activity.
- Metabolic and electrolyte balance normalized during recovery, indicating successful adaptation to stress.
Abstract:
Though children with febrile convulsions only have seizures in the early stage of a febrile illness and not later, these seizures have been attributed to the fever. We studied the serum electrolyte and metabolite profiles in the later stage to see if there were fuel responses resulting in electrophysiological changes which prevented further seizure activity. On admission there was intracellular glucose starvation, as evidenced by increased ketones and lactate, and the possibility of the failure of some electrolyte pumps, as suggested by hyperuricaemia (energy crisis) and decreased serum Na+, Cl- and Ca2+. However, there was adaptive hyperglycemia and decreased serum K+. It seems likely that the hyperglycemia, induced the uptake of K+ by neurones, enabling their repolarization and hyperpolarization, which prevented further seizure activity, while Cl- influx short-circuited depolarizing currents produced by Na+ influx. Studies during recovery showed a gradual return of the metabolic and electrolyte aberrations to normality, suggesting that the provision of energy through adaptation to the stress, enabled recovery of the aforementioned pumps.