In hydrocephalus due to outflow obstruction, the ventricular enlargement is typically which pattern?

In hydrocephalus due to outflow obstruction, the ventricular enlargement is typically which pattern?

• A. Symmetrical
• B. Asymmetrical
• C. Unilateral
• D. None

Answer: (A)

When CSF outflow is blocked inside the ventricular system, CSF keeps being produced and cannot escape, so pressure builds up throughout the connected ventricles. Because the obstruction affects the system as a whole rather than a single side, the dilation occurs in a coordinated, symmetric way, leading to enlargement of both lateral ventricles and the midline ventricles. This symmetric pattern is what’s typically seen in non-communicating (outflow obstructive) hydrocephalus. If the enlargement were clearly asymmetric, that would suggest a unilateral process such as a mass effect or partial, unilateral obstruction rather than a central outflow block.

When CSF outflow is blocked inside the ventricular system, CSF keeps being produced and cannot escape, so pressure builds up throughout the connected ventricles. Because the obstruction affects the system as a whole rather than a single side, the dilation occurs in a coordinated, symmetric way, leading to enlargement of both lateral ventricles and the midline ventricles. This symmetric pattern is what’s typically seen in non-communicating (outflow obstructive) hydrocephalus. If the enlargement were clearly asymmetric, that would suggest a unilateral process such as a mass effect or partial, unilateral obstruction rather than a central outflow block.