Normal pressure hydrocephalus (NPH)

Alternative Names

Hydrocephalus – idiopathic; Hydrocephalus – adult; Hydrocephalus – communicating; Extraventricular obstructive hydrocephalus

Definition of Normal pressure hydrocephalus (NPH)

Hydrocephalus refers to a build-up of fluid inside the skull, leading to brain swelling. Hydrocephalus means “water on the brain.”

Causes, incidence, and risk factors

Normal pressure hydrocephalus (NPH) is a form of , which means there is too much fluid pressing on the brain.


The symptoms often begin slowly.

Signs and tests

An examination shows walking (gait) changes related to the pressure placed on parts of the brain. Deep tendon reflexes may be increased in the lower legs.


The treatment of choice is surgery to place a tube called a that routes the excess CSF out of the brain ventricles. This is called a .

Expectations (prognosis)

Without treatment, symptoms often get worse and could lead to death.


Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 3/9/2010

Central nervous system
Ventricles of the brain

ADAM Medical Encyclopedia

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