Homovanillic acid and 5-hydroxyindoleacetic acid in the ventricular CSF of comatose patients with obstructive hydrocephalus.

Ventricular cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were determined every 2 to 4 hours over a period of 1 to 4 days in 12 patients, consisting of seven cases of brain tumor, two cases of cerebrovascular disease, and three cases of head injury. The concentrations of HVA and 5-HIAA varied with time in all cases, and significant correlations were found between the two values in eight cases. However, the relationship between variations of HVA and 5-HIAA levels and rhythms of sleep and waking could not be clarified. Both HVA and 5-HIAA concentrations varied at high levels in two patients whose CSF flow was completely blocked by tumor at the site of the fourth ventricle and aqueduct, respectively. On the contrary, in a case with craniopharyngioma in the third ventricle which blocked the bilateral foramina of Monro, although the HVA values were high, the 5-HIAA values varied at low levels. Of five comatose patients, two had cerebrovascular lesions and three had sustained head injury, and, in four of the five, the values of either one or both of HVA and 5-HIAA were low, but in the fifth case the 5-HIAA value was high. Estimation of HVA and 5-HIAA concentrations in ventricular CSF may be a valuable tool in the investigation of brain monoamine metabolism. However, many factors must be considered in the interpretation of results of clinical studies.