Specific Types & Syndromes
Idiopathic normal pressure hydrocephalus (iNPH)
Idiopathic normal pressure hydrocephalus is NPH with no identifiable cause, occurring mainly in older adults.
In short: Idiopathic normal pressure hydrocephalus (iNPH)
- It is NPH without an identifiable cause.
- It occurs mainly in older adults.
- It shows the classic triad of gait, cognitive, and bladder symptoms.
- It can be treated, often with a shunt, in selected patients.
What it is
Idiopathic normal pressure hydrocephalus (iNPH) is the form of NPH that occurs without an identifiable underlying cause, primarily in older adults. "Idiopathic" indicates that no specific cause (such as prior hemorrhage or infection) is found.
Understanding Idiopathic normal pressure hydrocephalus (iNPH)
iNPH presents with the classic triad — gait disturbance, cognitive decline, and urinary incontinence — and enlarged ventricles with normal-range CSF pressure. Because its symptoms overlap with other conditions of aging (such as Parkinson's disease or other dementias), careful evaluation is essential to identify patients likely to benefit from treatment. Tests such as a lumbar tap test or external lumbar drainage can help predict the response to a shunt. When iNPH is identified and patients are well selected, shunting can improve symptoms, particularly gait. The diagnosis and the decision to treat are individualized.
Why it matters
Understanding iNPH helps older adults and families see that an enlarged-ventricle condition with no identifiable cause can still be treatable, and why careful evaluation is used to identify who is likely to benefit from a shunt.
Common questions
What is iNPH?
NPH with no identifiable cause, mainly in older adults.
How is it evaluated?
With imaging and tests such as a lumbar tap test to predict shunt response.
Can it be treated?
Yes — often with a shunt, in well-selected patients.
Bottom line
Idiopathic normal pressure hydrocephalus is NPH without an identifiable cause in older adults, treatable with a shunt in selected patients.
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