Core Terms & Classification
Unilateral hydrocephalus
Unilateral hydrocephalus is enlargement of one lateral ventricle, usually due to a blockage at the foramen of Monro on that side.
In short: Unilateral hydrocephalus
- Only one lateral ventricle is enlarged.
- It often reflects a blockage at the foramen of Monro on that side.
- Causes include cysts, tumors, or scarring.
- It may be treated by relieving the specific blockage.
What it is
Unilateral hydrocephalus is enlargement of a single lateral ventricle, on one side of the brain. It reflects a localized problem affecting CSF flow from that ventricle.
Understanding Unilateral hydrocephalus
When only one lateral ventricle is enlarged, the cause is usually a blockage at the foramen of Monro on that side — the channel connecting the lateral ventricle to the third ventricle. The blockage can result from a cyst, tumor, or scarring. Because the trapped ventricle cannot drain, fluid accumulates on that side alone. Treatment may involve relieving the specific blockage, sometimes endoscopically (for example, by creating an opening in the septum between the ventricles).
Why it matters
Understanding unilateral hydrocephalus helps families see how a one-sided blockage produces enlargement of a single ventricle, and why treatment focuses on relieving that specific obstruction.
Common questions
Which ventricle is enlarged?
One lateral ventricle, on one side.
What usually causes it?
A blockage at the foramen of Monro on that side.
How is it treated?
By relieving the specific blockage, sometimes endoscopically.
Bottom line
Unilateral hydrocephalus enlarges one lateral ventricle, usually from a blockage at the foramen of Monro on that side.
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