[Study on the concentration of 5-hydroxyindoleacetic acid (5-HIAA) in the lumbar cerebrospinal fluid (CSF) in neurological diseases].

Experimental evidence has shown that the amount of 5-HIAA in the CSF reflects the metabolism of serotonin in the brain if this metabolite is eliminated from the brain and flows into the CSF at a constant rate. We studied the concentration of 5-HIAA in the lumbar CSF in several neurological diseases to elucidate the alteration in abnormalities of serotonin metabolism. The concentration of 5-HIAA in the CSF was measured in 94 patients with cerebral infarction, 30 with vascular dementia, 25 with dementia of the Alzheimer type, 28 with Parkinson's disease and 6 with hypoxic encephalopathy. Patients with cerebral infarction were classified into 24 with a solitary cerebral infarct and 70 with multiple cerebral infarcts. Patients with Parkinson's disease were subdivided into 12 with various psychiatric symptoms including depressive state, hallucination and/or intellectual impairment and 16 without psychiatric symptoms. Patients with hypoxic encephalopathy consisted of 5 with apallic syndrome and one patient with Lance-Adams syndrome. The concentration of 5-HIAA in solitary cerebral infarct, multiple cerebral infarcts and vascular dementia did not exhibit a significant difference from that in control cases (54.6 +/- 23.1 ng/ml). But patients with dementia of the Alzheimer type (34.5 +/- 10.9, p less than 0.001) showed a significantly lower concentration. This fact seems to reflect the pathological finding that the number of large neurons is decreased and neurofibrillary tangles are increased in the nucleus raphe dorsalis of patients with Alzheimer type dementia.(ABSTRACT TRUNCATED AT 250 WORDS)