OSMOLALITY AND ELECTROLYTES IN CEREBROSPINAL-FLUID AND SERUM OF FEBRILE CHILDREN WITH AND WITHOUT SEIZURES

During acute febrile diseases mild disturbances of water and electroly te balance occur frequently. It has been suggested that changes in ele ctrolyte balance, in particular hyponatraemia, might predispose a chil d to convulsions during febrile illness; however, the changes of elect rolytes in the CSF are not known. We have studied the effects of fever and convulsions on water and electrolyte balance in CSF and serum by measuring osmolality and electrolyte concentrations in children. The f ebrile population consisted of 60 children, 36 of whom had seizures du ring fever. Twenty-one children without convulsions and nine children with epileptic symptoms were nonfebrile controls. We noticed that CSF is subject to changes in osmolality and electrolyte concentration duri ng fever, while convulsions do not exhibit such changes. CSF osmolalit y and sodium concentrations were lower in febrile children than in non febrile controls. The osmolality in febrile children with convulsions was 3.8% (P < 0.01) and without seizures 3.5% (P < 0.01) lower than in nonfebrile nonconvulsive children. The changes in CSF sodium concentr ation, and to a lesser extent potassium and chloride concentrations, p aralleled those of CSF osmolality. A positive correlation was observed between the CSF and serum osmolatities (r = 0.73, P < 0.0001), and so dium concentrations (r = 0.63, P < 0.0001). A negative correlation bet ween the body temperature and both CSF osmolality (r = -0.66, P < 0.00 01) and sodium concentration (r = -0.59, P < 0.0001) exhibits also the important regulative role of increased body temperature. Conclusion F ever is an important factor for disturbances in fluid and electrolyte balance. The alterations in CSF osmolality and sodium concentration do not, however, give an unambiguous explanation for the susceptibility to simple febrile seizures.