AbstractHydrocephalus is the result of an imbalance between the formation and drainage of cerebrospinal fluid (CSF), characterized by an elevation of the CSF pressure within the brain. A primary method of its treatment is the surgical insertion of a shunt. The patient’s condition is usually improved and he or she attends the hospital for periodic controls, at which CSF can be easily and repeatedly collected. Unfortunately, the effect of the operation is not durable and the number of patients in which the improvement of the clinical stage is recorded sinks considerably, and many of them develop dementia. Various biochemical markers in CSF have been searched to assess the response to surgical treatment and the further prognosis. They include classic clinical biochemistry parameters, some proteins occurring in excess in patients with Alzheimer’s disease, other biomarkers generally reflecting the overall neuronal injury, and hormones, including steroids. The existing as well as the potential biomarkers enabling to predict the patient’s fate after shunt operation are critically reviewed here. Special attention is paid to corticosteroids with respect to their role in influencing electrolyte balance in choroidal cells and consequently CSF and water flow among the ventricles. The importance of the local activity of steroid 11β-hydroxysteroid dehydrogenase (11β-HSD) of both types for regulation of the actual corticosteroid concentration is emphasized, and an original method for determination of cortisol/cortisone concentration in CSF is described. Preliminary results showing the changes of 11β-HSD activity in ten patients with hydrocephalus immediately after shunt introduction and after 1 month are provided.