Normal Pressure Hydrocephalus, Dementia and Kynurenic Acid

Abstract

A female 49 years old patient with vestibular schwannoma developed normal pressure hydrocephalus. Patient complained about gait disturbance, urinary incontinence and memory impairment. Investigation of clinical parameter and measurement of kynurenic acid in the cerebrospinal fluid (CSF) and serum in patients with normal pressure hydrocephalus and in corresponding controls (CO; N=15) were performed. Within investigated parameters significant increase of protein and IgG levels in CSF were found in patient with normal pressure hydrocephalus. Furthermore, kynurenic acid was increased in the CSF by 60% and in the serum by 40%, comparing to CO subjects. Kynurenic acid level in CO was in the CSF and serum 2.77 ± 0.23 and 53.4 ± 4.0 nM, respectively. Three lumbar punctures were applied to patient with normal pressure hydrocephalus and clinical parameters partially normalized and lowering of kynurenic acid levels in CSF and serum were observed. Patient was improving after each lumbar puncture but the effect was transient, therefore permanent CSF shunting was recommended. After that a complete remission of symptoms occurred. Revealed data indicate a significant advantage of single punctures in management of treatment for normal pressure hydrocephalus. Increase of kynurenic acid in CSF represents interesting parameter. It is questionable if occurrence of cognition impairment and/or dementia in patients with normal pressure hydrocephalus might be related to an enhancement of kynurenic acid in the CNS.