Cerebrospinal fluid from 8 patients with
infantile spasms (mean age: 6.1 months) was collected before treatment. The concentration of cerebrospinal fluid
tryptophan metabolites was analyzed using high-performance liquid chromatography and compared to metabolite concentrations in cerebrospinal fluid from 20 age-matched controls (mean age: 5.8 months). The levels of cerebrospinal fluid
serotonin, 5-hydroxyindoleacetic
acid, and
kynurenine were significantly lower in
infantile spasm patients compared to controls (P less than .05). In contrast, the levels of cerebrospinal fluid
3-hydroxykynurenine were significantly higher in
infantile spasm patients than in controls (P less than .05). There were no significant differences in the levels of cerebrospinal fluid
tryptophan and
5-hydroxytryptophan. Although the study population was small, these findings suggest that the presence of
seizures in
infantile spasms is associated with a decrease in serotonergic metabolites which, in turn, may indicate a decrease in serotonergic activity, altered clearance of these metabolites, or altered turnover in the direction of
3-hydroxykynurenine. The perturbance caused by increased
3-hydroxykynurenine and decreased
kynurenine in the homeostatic balance between these 2
tryptophan metabolites could further contribute to the pathogenesis of
infantile spasms.