Hydrocephalus (secondary or idiopathic) is a condition characterized by dilatation of the lateral and third ventricles, and often associated with increased intracranial pressure (ICP). We hypothesize that either the ventricle dilatation or the increased ICP may cause disturbances in the hypothalamic-pituitary axis, resulting in different degrees of hypopituitarism. The goal of this study is to determine the prevalence of hypopituitarism in adult patients with hydrocephalus.