Febrile convulsions and blood-cerebrospinal fluid barrier.

Three single CSF proteins with different molecular size (albumin, immunoglobulin G, and alpha2-macroglobulin) were determined by the method of electroimmunoassay in 61 children with febrile convulsions (FC) in order to evaluate the permeability of the blood-CSF barrier (B-CSF-B). Forty-two children with acute extracerebral infection served as controls. In contrast to a group of 22 children who suffered from acute meningoencephalitis or encephalitis, the CSF values of 48 children with FC were within normal limits. Thus even a very mild form of inflammatory encephalopathy-undetectable with conventional CSF investigation-was excluded in the majority of the children with FC. In 11 patients, however, CSF concentrations of albumin and alpha2-macroglobulin were abnormally raised, indicating a B-CSF-B distrubance. Elevated albumin values were found most frequently. In several children with FC lasting more than 20-30 min, B-CSF-B damage was probably caused by prolonged seizure activity since there is a linear correlation between albumin concentration and duration of convulsions. Several other factors known to raise the children's risk of developing epilepsy in later life were associated with the protein pattern of B-CSF-B disturbance in some of the children. In these cases, the cause of abnormal permeability of B-CSF-B is unknown and the condition might have existed prior to the occurrence of seizures.