Serotonin and 5-hydroxy indole acetic acid in infantile hydrocephalus

The concentration of metabolites of neurohormones in cerebrospinal fluid (CSF) is an index of turnover of substances in brain parenchyma. The raised intracranial pressure in hydrocephalic children may cause alteration in the metabolism of neurohormones. Serotonin and its metabolite 5-HIAA have been studied extensively in CSF of patients with neuropsychiatric diseases. Hence we studied the neurohormones serotonin and its end product 5-hydroxy indole acetic acid (5-HIAA) in CSF of hydrocephalus infants before and after ventriculoperitoneal (VP) shunt. Ventricular CSF samples form 50 hydrocephalic infants were obtained serially at the time of shunt insertion, and then on day 8 and day 30 postoperatively by direct puncture from shunt chamber using 26G needles. Control CSF samples were taken from otherwise healthy children operated under spinal anesthesia. The samples were analyzed for serotonin and 5-HIAA by spectrofluorophotometric method. At the time of shunt insertion, serotonin was significantly decreased (P<0.05) while 5-HIAA was significantly increased (P<0.001) in hydrocephalic infants. On day 8 and day 30 values of serotonin and 5-HIAA approached the baseline values. In patients who developed VP shunt blockade there was again a rise in levels of 5-HIAA. However, no correlation could be established between the levels of serotonin, 5-HIAA and the duration of hydrocephalus and the type of hydrocephalus. Our study shows increased 5-HIAA concentration in CSF indicating increased turnover of serotonin to its metabolite due to pressure changes in hydrocephalus. Long-term follow-up is required to assess if they could be of prognostic significance as regards to long term attainment of brain functions in hydrocephalic children.