Normal Pressure Hydrocephalus (NPH)

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ABOUT NPH

Normal Pressure Hydrocephalus is a neurological condition which normally occurs in adults 55-years and older. NPH is an accumulation of cerebrospinal fluid (CSF) causing the ventricles of the brain to enlarge, in turn, stretching the nerve tissue of the brain causing a triad of symptoms.


How is NPH different from Alzheimer's or Parkinson's?

One quarter million Americans with some of the same symptoms as dementia, Alzheimer's, or Parkinson's may actually have NPH.

It’s often difficult to tell the difference because the symptoms of NPH are in many ways similar to those of Alzheimer’s or Parkinson’s. However, the feeling of feet glued to the floor, or difficulty walking is the first symptom to appear in NPH. And it’s different from, for example, Parkinson’s tremors. In Alzheimer’s, memory loss and confusion tend to be early symptoms, whereas in NPH these appear later. Fortunately, once NPH is confirmed, chances are it can be treated.

To find help for patients with Alzheimer's disease and their caregivers, please visit razadyneer.com.


More About Hydrocephalus

Hydrocephalus is an abnormal (excessive) accumulation of fluid in the head. The fluid is called cerebrospinal fluid, commonly referred to as CSF. The CSF is located and produced within cavities of the brain called ventricles. The function of CSF is to cushion the delicate brain and spinal cord tissue from injuries and maintain proper balance of nutrients around the central nervous system. Normally, the bloodstream absorbs most of the CSF produced on a daily basis. Every day your body produces a certain amount of CSF and that same amount of CSF is absorbed in the brain. When an imbalance occurs, an excess of CSF fluid builds up resulting in the condition known as hydrocephalus. Left untreated, hydrocephalus will create increased pressure in the head and may result in increased symptoms or brain damage.


SYMPTOMS OF NPH

Characterized by three primary symptoms, NPH patients usually exhibit:

* Gait disturbance (difficulty walking)
* Dementia or forgetfulness
* Urinary incontinence (bladder control)

However, not all symptoms are always apparent or present at the same time.

>> View a video of the NPH gait: http://www.lifenph.com/symptoms.asp


It's not just "old age"

Because these three symptoms are often associated with the aging process in general, and a majority of the NPH population is older than 60 years, people often assume that they must live with the problems or adapt to the changes occurring within their bodies. Symptoms can be present for months or even years before a person sees a physician. The symptoms of NPH seem to progress with time. The rate of progress is variable, and it is often a critical loss of function, or disability, that brings patients to their doctors. It seems that the longer the symptoms have been present, the less likely it is that treatment will be successful. As a general rule, the earlier the diagnosis, the better the chance for successful treatment, but some people experiencing symptoms for years can improve with treatment.

Gait disturbances range in severity, from mild imbalance to the inability to stand or walk at all. For many patients, the gait is wide-based, short, slow and shuffling. People may have trouble picking up their feet, making stairs and curbs difficult and frequently resulting in falls. Gait disturbance is often the most pronounced symptom and the first to become apparent.


Forgetfulness or mild dementia

Mild dementia can be described as a loss of interest in daily activities, forgetfulness, difficulty dealing with routine tasks and short-term memory loss. People do not usually lose language skills, but they may deny that there are any problems. Not everyone will have an obvious mental impairment.


Urinary incontinence

Impairment in bladder control is usually characterized by urinary frequency and urgency in mild cases, whereas a complete loss of bladder control (urinary incontinence) can occur in more severe cases. Urinary frequency is the need to urinate more often than usual, sometimes as often as every one to two hours. Urinary urgency is a strong, immediate sensation of the need to urinate. This urge is sometimes so strong that it cannot be held back, resulting in incontinence. In very rare cases, fecal incontinence may occur. Some patients never display signs of bladder problems.


DIAGNOSIS OF NPH

Diagnosis of NPH is often difficult due to the symptoms being similar to other disorders. In many cases the NPH is thought to be mild dementia, Alzheimer's, Parkinson's or simply old age factors. Many cases go completely unrecognized and are never treated.

Usually, NPH causes the ventricles to enlarge due to increased CSF within the skull. If a person exhibits symptoms of hydrocephalus a physician may perform several tests to determine if shunting is an option. The most common diagnostic tools are neuro-imaging devices such as CT or MRI and a careful clinical assessment. Once the diagnosis of NPH is suspected there is no single perfect test to determine if a patient will respond to the shunt.


Finding a Specialist

At this point in the diagnostic process, it is important that a neurologist and a neurosurgeon become part of your medical team, along with your primary care physician. Their involvement from the diagnostic stage onward is helpful not only in interpreting test results and selecting likely candidates for shunting, but also in discussing the actually surgery and follow-up care as well as expectations of surgery. The decision to order a given test may depend on the specific clinical situation, as well as the preference and experience of your medical team.

To locate a specialist in your area, please use our Find a Specialist service.
http://www.lifenph.com/finding.asp


Diagnostic procedures

Diagnostic procedures for normal pressure hydrocephalus may include one or more of these tests: ultrasound, computerized tomography (CT), magnetic resonance imaging (MRI), lumbar puncture or tap, continuous lumbar CSF drainage, intracranial pressure (ICP) monitoring, measurement of cerebrospinal fluid outflow resistance or isotopic cisternography, and neuropsychological testing.


Ultrasound: a device that uses sound to outline the structures within the skull.

CT Scan (Computerized Tomography): creates a picture of the brain by using x-rays and a special scanner. It is safe, reliable, painless, and relatively quick (about 15 minutes). An x-ray beam passes through the head, allowing a computer to make a picture of the brain. A CT will show if the ventricles are enlarged or if there is obvious blockage.

MRI: is safe and painless, and will take approximately 30 minutes or longer. MRI uses radio signals and a very powerful magnet to create a picture of the brain. It will be possible to detect if the ventricles are enlarged as well as evaluate the CSF flow and provide information about the surrounding brain tissues. The MRI provides more information than the CT, and is therefore the test of choice in most cases.

MRI scans can also assess how fast CSF moves through a particular part of the brain called the cerebral aqueduct. Patients with cardiac pacemakers or certain other metallic implants cannot have MRI scans because of potential interference with the pacemaker.

Lumbar Puncture or spinal tap: This allows an estimation of CSF pressure and analysis of the fluid. Under local anesthetic, a thin needle is passed into the spinal fluid space of the low back. Removal of up to 50 cc of CSF is done to see if symptoms are temporarily relieved.

If removal of some CSF dramatically improves symptoms, even temporarily, then surgical treatment may be successful. All physicians do not advocate the use of a lumbar puncture as a screening test for NPH since many people who experience little or no improvement after the test may still improve with a shunt.

Lumbar catheter insertion: This is a variation of the lumbar puncture. A spinal needle is inserted in the spinal fluid space of the low back, then a thin, flexible tube (catheter) is passed into the spinal fluid and the needle is removed. The lumbar catheter allows for continuous and more accurate recording of spinal fluid pressure, or for more continuous removal of spinal fluid over several days to imitate the effect that a shunt would have. Patients who respond dramatically to such spinal fluid drainage are likely to respond to shunt surgery.

Intracranial pressure monitoring: ICP monitoring requires admission to the hospital. A small pressure monitor is inserted through the skull into the brain or ventricles to measure the ICP. The pressure is not always high, and pressure monitoring (either by lumbar catheter or the intracranial method) can detect an abnormal pattern of pressure waves.

Measuring CSF outflow resistance: This is a more involved test that requires a specialized hospital setting. In essence, this test assesses the degree of blockage to CSF absorption back into the bloodstream. It requires the simultaneous infusion of artificial spinal fluid and measurement of CSF pressure. If the calculated resistance value is abnormally high, then there is a very good chance that the patient will improve with shunt surgery. Isotopic cisternography: This procedure involves having a radioactive isotope injected into the lumbar subarachnoid space (lower back) through a spinal tap. This allows the absorption of CSF to be evaluated over a period of time (up to 96 hours) by periodic scanning. This will determine whether the isotope is being absorbed over the surface of the brain or remains trapped inside the ventricles. Isotopic cisternography involves spinal puncture and is considerably more involved than either the CT or MRI. This test has become less popular because a "positive" cisternogram result does not reliably predict whether a patient will respond to shunt surgery.

Neuropsychological Test: This testing involves asking a series of questions used to determine if there is a loss of brain function due to hydrocephalus.



TREATING NPH

The treatment of choice for NPH patients who show a positive response to diagnostic testing is the placement of a CSF shunt. A shunt is an implantable device designed to drain CSF fluid away from the brain thereby allowing the enlarged ventricles to return to a normal state. As CSF fluid builds and the pressure in the ventricle increases, a one-way shunt in the shunt opens, and the excess CSF fluid drains into the abdomen where it is easily absorbed. This technique is very effective in improving the troubling symptoms of NPH.

With a traditional fixed pressure shunt, choice of the correct pressure setting is very important as under-drainage will not improve symptoms, whereas over-drainage can cause symptoms in itself, or predispose to problems such as subdural hematoma. Incorrect choice of a fixed pressure shunt requires removal of the original shunt, and repositioning of a different one.

Surgical revisions such as this can be avoided if your neurosurgeon is certified in the use of programmable shunt technology. With a programmable shunt, the pressure setting can be adjusted with a special magnetic programmer in your doctor's office, eliminating the need for additional surgery if the initial setting proves not to help.


>> What is a Shunt?

Shunt systems come in a variety of models but always have two similar components: a catheter, the tubing that transports and diverts the CSF from the ventricles to either the abdominal cavity or right atrium, and a shunt that regulates the pressure or flow of CSF from the ventricles. Valves are manufactured to operate at a specific pressure range. A surgeon chooses a pressure range for the shunt based on experience and the needs of the patient.

Many shunt systems also have a flexible flushing chamber called a reservoir. The reservoir may be housed within the shunt system or added as a component along with the shunt system. The reservoir serves several important functions. It permits the doctor to remove samples of CSF for testing, using a needle and syringe. The doctor also may inject fluid into the shunt system to test for flow; to be sure the system is functioning.

The parts of a shunt system are named according to where they are implanted (placed) in the body. The portion of the tube which is inserted into the ventricles is called the ventricular catheter. The peritoneal catheter is the portion of the tube that drains CSF into the abdominal or peritoneal cavity.

If a drainage tube is placed into the right atrium of the heart it is called the atrial catheter. To get a better understanding of what a shunt system looks like, ask your doctor or nurse to show you samples of the shunts they use. All of the components of a shunt system are made from materials which are well known to be tolerated by the body. For this reason, the entire shunt system is implanted under the skin. There are no external parts.


>> Codman Programmable Shunt

Programmable Shunt Use of a programmable shunt can significantly increase the probability of shunt implantation being a one-time procedure. If the pressure setting of a fixed pressure shunt proves to be a mismatch after surgery, causing underdrainage or overdrainage complications, the patient must undergo a complete or partial shunt revision, sometimes more than once. This is a limitation of all fixed pressure shunts.

The CODMAN® Programmable Shunt gives your doctor a choice of 18 different programmable pressure settings. It is the same size as traditional fixed pressure shunts and is implanted in exactly the same way. Using an exclusive external programming device, the surgeon selects the initial pressure setting prior to the procedure, and can then easily adjust the setting at any time and as many times as necessary without further surgery. The large range of pressure settings allows the surgeon to make very fine adjustments in the pressure in order to get the best resolution of symptoms after the shunt is implanted. The totally non-invasive adjustments take only seconds and can be done right in the office with little or no patient discomfort.

Programming Device

Programming Device The device used to adjust the pressure setting of the shunt is simply called a Programmer. The programmer includes an electrical box connected to a round transmitter head. Using the transmitter head, the shunt is programmed to a certain pressure chosen by the surgeon prior to being implanted in the patient. Upon pushing a button, the shunt is changed to the selected pressure in 5 to 10 seconds. No additional surgeries or hospital visits are needed in order to reprogram the shunt.

Locating a Specialist

To find a neurosurgeon certified in the use of the CODMAN® Programmable Shunt, please use our Find a Specialist service and look for this seal.

If you are a physician interested in learning more about the CODMAN® Programmable Shunt, please contact Codman Customer Support at 1-800-225-0460.


>> Surgery

Surgery Diagram The surgical procedure to implant a VP (ventricular peritoneal) shunt usually requires less than an hour in the operating room. After the patient is placed under general anesthesia, their scalp is shaved and the patient is scrubbed with an antiseptic from the scalp to the abdominal area. These steps are taken in order to reduce the chances of an infection. Incisions are then made on the head and in the abdomen to allow the neurosurgeon to pass the shunt's tubing through the fatty tissue just under the skin. A small hole is made in the skull, opening the membranes between the skull and brain to allow the ventricular end of the shunt to be passed through the brain and into the lateral ventricle. The abdominal (peritoneal) end is passed into the abdominal cavity through a small opening in the lining of the abdomen where the excess CSF will eventually be absorbed. The incisions are then closed and sterile bandages are applied.

After surgery

The patient generally stays under careful neurological observation for the first 24 hours following the procedure. Some neurosurgeons prefer to keep the patient flat in bed until nearly all the subdural air introduced during surgery dissipates. The bandages placed on the head and abdomen, covering the incision sites, are monitored for signs of infection. The patient will generally need to stay in the hospital from three to seven days. Follow-up visits will be necessary to check post-operative status and resolution of symptoms. Additional treatment, such as physical therapy, may be advised to help the patient attain previous levels of motor skills.

Possible complications

Although shunt surgery is a relatively simple neurosurgical procedure, the decision to undergo insertion of a shunt should not be taken lightly. The treatment of normal pressure hydrocephalus carries greater risks compared to the treatment of children with hydrocephalus, and therefore the operation should be undertaken only if the degree of disability or the progression of the disorder warrants.

The potential complications of shunt surgery should be viewed as those related to the actual operation, plus those that may occur days to years later. A complication can be thought of as any unwanted event related to the surgical procedure itself or the presence of the shunt. Potential complications may include the infection of the surgical wound or of the CSF (meningitis), bleeding into the brain or ventricles, or a seizure. A shunt infection may be indicated by fever, redness or swelling along the shunt track. Fortunately, these complications are uncommon and can be managed successfully in most cases.

Unlike may other operations in which the surgical risks are highest during the operation itself, most of the common and serious problems associated with shunting can occur weeks or even years after the surgery. The most common problem with shunt systems is that they can become obstructed (clogged). This can occur hours or years after the operation, sometimes multiple times. The likelihood of a shunt obstruction is thought to be about 50% for most patients. For patients with NPH, a shunt obstruction is usually discovered when the original symptoms recur. Fortunately, shunt obstructions in NPH are easily fixed and rarely result in serious problems.

The most serious complication that can occur following insertion of a shunt is a subdural hematoma (blood clot). Because most shunts drain CSF from the center of the brain (the ventricles), this may cause the surface of the brain to pull away from the skull, thus stretching and tearing blood vessels on the surface of the brain. The symptoms of a subdural hematoma vary from increasing headache to paralysis or even coma or death. Shunt-related subdural hematomas most commonly occur following a fall, even one involving only a minor bump to the head. Therefore, a patient with NPH should not hesitate to seek medical attention if abnormal symptoms develop. The risk of a subdural hematoma in a patient with NPH is approximately 10%. Given these potential complications, individuals need to assess their own situation to determine if the possible benefits of surgery outweigh the possible risks.


>> Outcome & Recovery

If the cause of NPH is known, success rates can be as high as 80 percent. In cases in which a cause is not known, the success rate varies from 25 to 74 percent.

Neurosurgeons do not agree on the factors that lead to a successful shunting procedure nor do they have similar success rates. The higher success rates, however, have been reported from medical centers using the more demanding diagnostic tests such as lumbar catheters or the measurement of CSF outflow resistance. It is important to note that if initial success is followed by a recurrence of symptoms, it may be due to a shunt or shunt failure, the need for shunt pressure re-programming (in the case of a programmable shunt) or simply a lower pressure shunt rather than failure of the procedure.

Rate of Improvement

The symptoms of gait disturbance, mild dementia and bladder control problems may improve within days of shunt surgery, or may take weeks to months to abate. However, there is no way to predict how fast, or to what extent, this improvement will occur. For patients who do improve, changes are seen in the first week in most cases. In addition, this improvement may range from mild to dramatic. It is also not possible to make general predictions of how long the improvement will last, as the course of clinical improvement varies for each patient. Some patients seem to reach a plateau, while others improve for months but then seem to decline again. Unfortunately, there are no guarantees.

Generally, patients with an implanted shunt system are not restricted in their daily activities, except those involving great physical exertion. Your doctor will discuss with you any restrictions that may be advisable. Most patients with hydrocephalus can look forward to a normal future. Shunts are expected to perform reliably over a long period of time. However, because hydrocephalus is an ongoing condition, patients do require long term follow-up care by a doctor. Having regular medical checkups at intervals recommended by the neurosurgeon is sensible.

Shunt Revisions

Occasionally, patients with shunt systems require revisions. A revision is a surgical procedure to modify, repair or replace a shunt system due to complications or changing patient conditions. In those cases where a change in shunt pressure is needed, a patient with a programmable shunt system will simply require their shunt to be externally (without surgery) re-programmed.

The patient or family of the patient must be responsible for follow-up care. Regular follow-up visits will help the neurosurgeon to identify any subtle changes that may be indicative of a shunt problem. Patients and family members should become familiar with the signs and symptoms of shunt malfunction as described below.

Some Symptoms of Shunt Malfunction

* Headache
* Vision Problems
* Irritability
* Tiredness
* Personality Change
* Loss of Coordination or Balance
* Difficulty in Waking Up or Staying Awake
* Return of Gait Disturbance
* Mild Dementia
* Incontinence


This list of symptoms is for your reference only, and is not a diagnostic aid. If you are in doubt about your condition or a family member's medical condition, consult your physician immediately or click here to locate a specialist in your area.
http://www.lifenph.com/finding.asp