noun
hydrocephalus
high-droh-SEF-uh-lus/ˌhaɪdrəʊˈsefələs/
An abnormal buildup of cerebrospinal fluid in the brain's cavities.
In hydrocephalus, excess cerebrospinal fluid collects in the brain's cavities.

Etymology
The water and head roots express the traditional description “water on the brain.” The name refers to an abnormal accumulation of fluid within the head, rather than the body's ordinary need for water.
In context
had headache the tumor was large and it was compressing on the brain stem and it was also causing a lot of buildup of fluid in the brain called as hydrocephalus
More examples
- Both infants and adults can develop hydrocephalus.
- A shunt drains excess fluid in some patients with hydrocephalus.
- Doctors use brain scans to help diagnose hydrocephalus.
Forms
hydrocephalic adjective — Relating to or affected by hydrocephalus.