Hydrocephalus is a neurological disorder caused by an abnormal buildup of cerebrospinal fluid in the ventricles (cavities) deep within the brain. This excess fluid causes the ventricles to widen, putting harmful pressure on the brain's tissues. Hydrocephalus may be present at or shortly after birth, or may result over time from damage or injury.

Normal Pressure Hydrocephalus Causes. In most cases, the cause of NPH isn’t known, but several things can lead to it, including: A head injury. Bleeding around the brain (due to a blow to the.