Core Terms & Classification
Tetraventricular hydrocephalus
Tetraventricular hydrocephalus is enlargement of all four ventricles, suggesting a problem beyond the ventricular outlets.
In short: Tetraventricular hydrocephalus
- All four ventricles are enlarged.
- It suggests the blockage or problem is beyond the fourth ventricle's outlets.
- It can occur in communicating hydrocephalus.
- The pattern helps localize the underlying problem.
What it is
Tetraventricular hydrocephalus is enlargement of all four ventricles — both lateral ventricles, the third, and the fourth. The involvement of all four points to where the problem lies in the CSF pathway.
Understanding Tetraventricular hydrocephalus
When all four ventricles are enlarged, the problem typically lies beyond the outlets of the fourth ventricle — for example, at the level of CSF flow over the brain or absorption (as in communicating hydrocephalus), or from a blockage at the fourth ventricle's outlets. This contrasts with triventricular hydrocephalus, where the fourth ventricle is spared and the blockage is at the aqueduct. The pattern of which ventricles are enlarged helps doctors localize the underlying problem and choose treatment.
Why it matters
Understanding tetraventricular hydrocephalus helps families see how the pattern of all four enlarged ventricles points toward a problem beyond the ventricles themselves, which influences the type and approach to treatment.
Common questions
Which ventricles are enlarged?
All four.
What does this pattern suggest?
A problem beyond the fourth ventricle's outlets, such as in absorption.
How does it differ from triventricular?
Triventricular spares the fourth ventricle; tetraventricular does not.
Bottom line
Tetraventricular hydrocephalus enlarges all four ventricles, suggesting a problem beyond the ventricular outlets.
Browse all 265 Hydrocephalus definitions
Read the Hydrocephalus patient guides
Not sure which page you need? Put words to it with the symptom navigator