Core Terms & Classification

Active (progressive) hydrocephalus

Active hydrocephalus is hydrocephalus that is ongoing and progressing, with continued fluid buildup or rising pressure that usually needs treatment.

In short: Active (progressive) hydrocephalus

  • The fluid buildup or pressure is continuing to worsen.
  • It typically requires treatment.
  • It contrasts with arrested or compensated hydrocephalus.
  • It is monitored through symptoms, head size, and imaging.

What it is

Active or progressive hydrocephalus is hydrocephalus in which the buildup of CSF or the associated pressure is ongoing and worsening over time. This is the situation in which treatment is generally needed.

Understanding Active (progressive) hydrocephalus

When hydrocephalus is active, the ventricles continue to enlarge or pressure continues to rise, producing symptoms or signs (such as increasing head circumference in a baby, headaches, or changes in alertness). This contrasts with hydrocephalus that has stabilized (arrested) or is balanced without symptoms (compensated). Active hydrocephalus usually requires intervention — such as a shunt or ETV — to relieve the buildup and protect the brain. The care team monitors for activity through symptoms, head size, and imaging.

Why it matters

Understanding active hydrocephalus helps families recognize that progression is the key reason treatment is needed, and why symptoms, head size, and imaging are monitored to detect whether the condition is worsening.

Common questions

What makes hydrocephalus "active"?

The fluid buildup or pressure is ongoing and worsening.

Does it need treatment?

Typically yes.

How is activity monitored?

Through symptoms, head size, and imaging.

Bottom line

Active (progressive) hydrocephalus is worsening over time and generally requires treatment to relieve the buildup.

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