What Is Hydrocephalus?

A hydrocephalus MRI scan and a normal MRI scan
Hydrocephalus (pronounced hi-dro-SEF-a-lus) is a potentially harmful build up of cerebrospinal fluid (CSF) in parts of the brain.
Hydrocephalus literally means water (hydro) in the head (cephalus). It is sometimes called water on the brain. The "water" is actually cerebrospinal fluid. Cerebrospinal fluid is normally present in areas both inside and outside the brain.

Common causes of CSF blockage, which causes hydrocephalus
Children with hydrocephalus have too much cerebrospinal fluid in the areas of the brain called ventricles. The ventricles store and circulate cerebrospinal fluid. Children with hydrocephalus may also have extra fluid in spaces between the brain and the skull called the subarachnoid spaces.
When a child’s cerebrospinal fluid cannot flow or be reabsorbed properly, it builds up. This makes the ventricles bigger and puts pressure on the tissues of the brain.
Hydrocephalus in Children
Babies can be born with hydrocephalus (congenital). About one in every 1,000 babies has the condition.
Hydrocephalus can also develop anytime after birth. This is called acquired hydrocephalus. Acquired hydrocephalus can develop for many reasons, including:
- Bleeding inside a brain ventricle (intraventricular hemorrhage)
- Head injury
- Brain infection
- Brain tumor
Hydrocephalus at Seattle Children’s
Hydrocephalus is a very common problem for children who have other neurological disorders. Our team has a great deal of experience treating hydrocephalus. We do about 200 surgeries a year for hydrocephalus.
Many children need several operations for hydrocephalus during childhood. Our team includes experts who can take care of your child as they grow.