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

Normal pressure hydrocephalus (NPH) is a rise in cerebrospinal fluid (CSF) in the brain that affects brain function. However, the pressure of the fluid is usually normal.

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

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

NPH can occur without a known cause, or it may be caused by any condition that blocks the flow of cerebrospinal fluid (CSF). The fluid-filled chambers (ventricles) of the brain enlarge to fit the increased volume of CSF. They press down on and damage or destroy brain tissue.

Risk factors include:

• Bleeding from a blood vessel or aneurysm in the brain (subarachnoid hemorrhage)
• Closed head injury
• Meningitis or similar infections
• Surgery on the brain (craniotomy)

CSF is produced in normal amounts in these conditions, but it is prevented from being reabsorbed normally.

NPH is thought to account for about 5% of all dementias.

Images

Central nervous system

Ventricles of the brain

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Normal pressure hydrocephalus (NPH) Symptoms

Review Date: 03/09/2010
Reviewed By: 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.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)