LOW-SODIUM LEVELS IN SERUM ARE ASSOCIATED WITH SUBSEQUENT FEBRILE SEIZURES

Fever plays an important role in causing disturbances in fluid and ele ctrolyte balance. Hyponatraemia has been thought to enhance the suscep tibility to seizures associated with febrile illnesses in childhood. W e have studied serum electrolyte levels in children with simple and co mplicated febrile convulsions. Sodium levels were lower in those child ren with complicated convulsions in comparison with those having simpl e convulsions (136.07 +/- 3.06 mmol l(-1), mean +/- SD, n = 42, and 13 7.62 +/- 2.63 mmol l(-1), n = 71, respectively; p < 0.01, Student's I- test). The sodium concentrations were lowest in children with repeated seizures (134.20 +/- 2.30 mmol l(-1), n = 15) compared with children having simple (p < 0.01, ANOVA, Duncan's test) or other complicated ty pes of febrile convulsions: focal seizures (137.08 +/- 3.82 mmol l(-1) , n = 12, p < 0.01), seizures lasting longer than 15 minutes (138.00 /- 2.45 mmol l(-1), n = 5, p < 0.05) and children over 5 years (136.70 +/- 2.06 mmol l(-1), n = 10,p < 0.05). Serum potassium levels showed no statistically significant differences between the patient groups. O ur results show that hyponatraemia may increase the risk for multiple convulsions during the same febrile illness.