Hydrocephalus SNOMEDCT_US:230745008 HP:0008503 HP:0000238 human_phenotype Hydrocephalus results from an imbalance between the rate of production of cerebrospinal fluid (CSF), mainly in the choroid plexus, and its reabsorption in the subarchnoid space over brain and spinal cord. HP:0007189 Nonsyndromal hydrocephalus Hydrocephaly UMLS:C0020255 Too much cerebrospinal fluid in the brain Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation. MSH:D006849 Abnormality of the cerebral ventricles Abnormality of the cerebrospinal fluid