Types of Hydrocephalus
Hydrocephalus is a defect that causes excess cerebrospinal fluid (CSF) to build up in the brain. The brain is surrounded and cushioned by this fluid, which also fills open structures deep in the brain, called ventricles. With hydrocephalus, the fluid becomes trapped in the brain ventricles, which causes them to enlarge. We explain more about hydrocephalus here.
For most types of hydrocephalus, surgery is the only treatment option. On this page, we discuss the different types of hydrocephalus, which are classified according to the cause and symptoms of hydrocephalus.
Communicating vs Non-Communicating Hydrocephalus
There are two main classifications for hydrocephalus:
- Communicating hydrocephalus (or non-obstructive) – after the brain fluid becomes blocked, it can still flow between the ventricles.
- Non-communicating hydrocephalus (or obstructive) – the brain fluid becomes blocked in one or more of the narrow passages that connect the ventricles.
Both communicating and non-communicating hydrocephali can be subdivided into:
- congenital hydrocephalus (present at birth)
- acquired hydrocephalus (occurs following birth).
Communicating hydrocephalus can also be subdivided into:
- normal pressure hydrocephalus (NPH)
- hydrocephalus ex-vacuo.
The below image illustrates the two main types of hydrocephalus:
- non-communicating hydrocephalus is shown in the left scan;
- the right shows communicating, normal pressure hydrocephalus (NPH).
In a brain without hydrocephalus, the blue areas – which is the fluid on the brain – would be less visible.