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Adult Onset Normal Pressure Hydrocephalus


ADULT ONSET HYDROCEPHALUS Any hydrocephalus which appears in adulthood from a variety of causes, including head injury, stroke, meningitis,  or unknown cause. 

Small silicone tube, the part of the shunt which allows the Cerebral Spinal Fluid to circulate. 
Cerebrospinal Fluid is a clear bodily fluid which provides a cushion between the skull and the cerebral cortex.  It also occupies the ventricular system of the brain and the spinal cord.  The body makes almost a pint of this fluid daily.  It is in constant production, circulation, and absorption.  The fluid provides nourishment, carries away any debris (such as extra protein cells), and protects us from injury.

The chambers within the brain which contain Cerebral Spinal Fluid

CISTERNOGRAPHY Isotopic cisternography involves injecting a radioactive isotope into the lower back through a spinal tap. This allows the absorption of CSF to be monitored over a period of time (up to 4 days of hospitilization)
CSF See Cerebrospinal Fluid
Also described as "non-obstructive", this type of hydrocephalus is caused by a lack of absorption of the cerebral spinal fluid rather than a blockage.

Computed Tomography  (CT) Scan of the head uses an x-ray beam, which passes through the head allowing a computer to make a picture of the brain in slices.  A CT will show if the ventricles are enlarged or if there is an obvious blockage.

DEMENTIA Loss of mental function. Caused by head injury, disease (such as Alzheimers Disease or Hydrocephalus), stroke, or medication. It can also be caused by a  deficiency in Vitamin B12 or other chemical imbalance. Sometimes cause is unknown. May be exhibited by mild confusion or profound mental disability. 

ETV Endoscopic Third Ventriculostomy (ETV) is a surgical procedure which involves making a hole in the floor of the third ventricle to allow free flow of spinal fluid into the basal cisterns for absorption. It is not commonly used to treat communicating hydrocephalus, but it has been successful in some cases.
External Ventricular Drain (EVD) is device somewhat similar to a shunt, functioning  on the outside of the body.  A catheter is implanted into the brain to drain the excess CSF (Cerebral Spinal Fluid).  The flow is regulated by either raising or lowering the bag (where the fluid is emptied into).

In a fixed shunt, the valve is pre-set for high, medium, or low pressure.

Hospital Psychosis usually is a temporary period of anxiety, and even delusions or hallucinations caused by the stressful environment of the hospital.  It is often difficult to diagnose, since medications, anesthesia, and changes in the CSF pressure in the brain may cause similar symptoms in some patients.  For more about Hospital Psychosis, visit this LINK

Hydrocephalus results from the accessive accumulation of cerebrospinal fluid in the brain.  It can be congenital or develop later in life from known or unknown causes.

Intracranial Pressure Monitor.  The placement of an Intracranial Pressure Monitor allows for a period of continuous recording of intracranial pressure. It allows the identification of episodic waves of high pressure that are missed with isolated lumbar measurement. A catheter or small fiber optic cable is inserted  through the skull into the brain.  This procedure requires approximately 24 hours of hospitalization.
The dictionary says, "arising spontaneously or from an obscure or unknown cause"
Inability to prevent discharge of urine or feces.  Urinary urgency or incontinence is a common symptom of Normal Pressure Hydrocephalus.
ISOTOPIC CISTERNOGRAPHY Isotopic cisternography involves injecting a radioactive isotope into the lower back through a spinal tap. This allows the absorption of CSF to be monitored over a period of time (up to 4 days of hospitilization)

LATERAL VENTRICLE There are two Lateral Ventricles,  small chambers beneath the surface of the brain that contain Cerebrospinal Fluid. Most of the CSF is made by the choroid plexus that lays on the floor of the lateral ventricles; CSF must pass from the right and left lateral ventricles.  These are the ventricles affected by Normal Pressure Hydrocephalus.


Lumbar puncture (spinal tap) can be used to measure CSF pressure and analyze the fluid.  A LUMBAR DRAIN helps indicate whether a shunt, the common treatment for hydrocephalus, may be successful. Typically, it is conducted over a period of three or four days in the hospital while volume of Cerebrospinal Fluid removed is monitored.   Even temporary improvement of symptoms is encouraging for the success of a shunt in treating the hydrocephalus.  More on Lumbar Drain.


The CSF (Cerebrospinal Fluid)  is shunted from the lumbar sub-arachnoid spaces to the peritoneal cavity.

Magnetic Resonance Imaging is non-invasive, using radio signals and a powerful magnet to show the anatomical structures of the brain. It can reveal if the ventricles are enlarged and evaluate the CSF flow.

Non-Communicating Hydrocephalus is caused by a blockage of the flow of CSF (Cerebral Spinal Fluid). It may have a number of causes, including congenital birth defect, brain tumor, brain injury.
NORMAL PRESSURE HYDROCEPHALUS Normal Pressure Hydrocephalus is a "communicating" or "non-obstructive" type of hydrocephalus.  The distinguishing feature is the lack of absorption rather than the excess formation of fluid causing increased pressure.  Except for occasional spikes in pressure, the pressure is "normal".  The condition may have a number of causes, or the cause may never be known.  It typically is diagnosed in patients over 55.
NPH Normal Pressure Hydrocephalus
See Non-Communicatng Hydrocephalus.

OVER-DRAINAGE Over-Drainage is a condition in which too much CSF is withdrawn from the cerebral ventricles. Usually symptoms are noticed after being upright for awhile, and they can include headache or migrane in the morning within an hour of getting up, dizziness, nausea and vomiting. Over draining can result in 'slit ventricle syndrome.  Also called SYPHONING.
PERITONEUM The thin lining of body cavities; CSF can be absorbed easily through the peritoneum lining the abdominal cavity.

A shunt which offers valve adjustment without surgery using a programming device. 
SHUNT In simple terms, the shunt is a mechanical system that drains cerebrospinal fluid from the brain to another cavity in the body.  The basic components of a shunt are a silicone tube implanted in the ventricles of the brain, and the valve may be fixed (set to low, medium or high) or programmable (adjustable).  The tube leads to a valve which regulates Cerebrospinal Fluid pressure, and adjusts to allow fluid to be released to a second tube.  Typcially this tube is routed under the skin to release the fluid into the Peritoneal Cavity (lower abdomen) or the right atrium of the heart where it is absorbed by the body.   See also:  VENTRICULO-ATRIAL SHUNT (V-A),  VENTRICULO-PERITONEAL SHUNT  (V-P),  LUMBO-PERITONEAL SHUNT (L-P)

More about Shunts (with diagrams)

A series of X-Rays which follow the continuum of the shunt, from the valve through the entire system.  It is usually used in conjunction with the CT scan to identify any problems.
Syndrome of Hydrocephalus in Young and Middle-aged Adults as described by Dr. Michael Williams.  See  Hydrocephalus Association web site.

The ventricles become slit-like in reaction to over-draining by the shunt.  This often happens in children who have been shunt dependent for several years.  It may cause headaches but may be asymptomatic.  http://virtualtrials.com/shunts.cfm

THIRD VENTRICLE The Third Ventricle is the thin chamber deep in the brain that contains CSF and connects the lateral ventricles to the cerebral aqueduct; CSF must flow through the third ventricle in order to exit the brain.

The surgical process of making a small hole in the floor of the third ventricle so that CSF can escape into the subarachnoid space. This procedure is used most often with pediatric cases of obstructive (non-communicating) hydrocephalus.  Normal Pressure Hydrocephalus is a communicating hydrocephalus. Sources: Wayne State University

Under draining occurs when not enough Cerebral Spinal Fluid (CSF) is taken.  Symptoms usually come about when the patient is either laying down or reclining the body at an angle.  Patient usually wakes up with a headache and it disappears after he/she has been upright for 45 minutes to an hour (average).

See Ventriculo-Atrial Shunt

There are 4 chambers in the brain, called Ventricles, which produce the cerebral spinal fluid.  The lateral (2) ventricles - one is located on the left and right side of the brain's hemispheres, the third is located in the middle, and the 4th is low and located at the back of the skull.The chambers within the brain which contain Cerebrospinal Fluid. Images of the Ventricles of the brain.
Shunt which drains the CSF (Cerebrospinal Fluid) into the right atrium of the heart to be absorbed into the blood stream. 

Shunt which drains the CSF (Cerebrospinal Fluid) into the abdominal cavity to be absorbed by the peritoneum lining. This is the type of shunt most often used to treat Normal Pressure Hydrocephalus.
Ventriculo-Gallbladder Shunt
 Shunt which drains the CSF into the gallbladder.
See Ventriculo-Peritoneal Shunt

Thanks so much to Debbi Fields, Director of the National Hydrocephalus Foundation, for her help with these definitions, and her assistance and expert advice to this group. 

Other Sources:

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