Normal Pressure Hydrocephalus (NPH)
What is hydrocephalus?
The brain and spinal cord float in a fluid called Cerebrospinal Fluid (CSF). This fluid is made in spaces within the brain called ventricles. After the fluid flows around the brain and spinal cord, it is reabsorbed by the brain.
Hydrocephalus, which means “water on the brain,” occurs when the CSF is not reabsorbed as fast as it is made, or when there is a blockage of the pathways where CSF flows. Often, hydrocephalus is diagnosed because pictures of the brain show the ventricles to be larger than normal, though large ventricles do not always mean hydrocephalus. Our brains do get somewhat smaller as we age or with other conditions. When this happens, the ventrciles appear larger.
What is NPH?
Normal Pressure Hydrocephalus (NPH) is a syndrome affecting older people in which the ventricles (fluid-filled spaces in the brain) are enlarged, but the pressure inside the skull remains normal most of the time.
There are three key symptoms of NPH:
- Unsteady walking (gait apraxia)
- Memory loss (dementia)
- Loss of bladder control (urinary incontinence)
Not all patients with NPH have all three symptoms, though all seem to have problems with their walking.
Even though the pressure inside the skull is normal, these symptoms get better (or at least stop getting worse) with drainage of the spinal fluid (shunting) to some place in the body that can absorb the fluid more easily, usually the abdominal cavity. It is important to remember that large ventricles do not always mean someone has NPH as diagnosis cannot be made based on pictures alone.
What causes NPH?
There are two types of NPH:
- Primary or Idiopathic NPH: cause is unknown, although there are linkages to high blood pressure and glaucoma.
- Secondary NPH: caused by a illness, such as prior bleeding in or around the brain, meningitis, closed head injury or brain surgery. Surgery for secondary NPH has a response rate of aroximately 75 percent, which is higher than that described for idiopathic NPH. Given the excellent outcomes, patients with this history need to be identified and referred to a neurosurgeon as soon as possible.
How is NPH diagnosed?
The diagnosis of NPH is difficult. There is no gold-standard test for NPH. Other conditions can cause the symptoms of NPH, so other health problems (such as Alzheimer's disease, cervical spine disease, medication side effects and sleep apnea) need to be ruled out and/or treated before shunting for NPH is considered. In addition to a complete history and physical, there are tests which seem to be helpful in predicting who will benefit from surgery. Imaging, such as MRI and CT, can be helpful.
Temporary drainage of CSF can be performed as a trial run of shunting, either with a single spinal tap to remove a large volume of CSF, or with CSF drainage over 2 or 3 days through a drain placed in the spine. Collecting CSF can also be helpful in diagnosing other conditions which might be causing the symptoms. Thorough tests of thinking, memory and walking, performed before and after removal of CSF, aid in diagnosis and help us follow our patients’ progress over time.
The people who do best with shunting have the following characteristics:
- All three symptoms of unsteady walking, memory loss and loss of bladder control present
- Unsteady walking was the first symptom to occur and is the most bothersome problem
- Symptoms have been present for a short time (< 1 year)
However, it is still difficult to know whether shunting will help. Shunting may still help if other conditions are present, but outcomes may not be as good without successfully treating those conditions.
For example, some people have both NPH and cervical spinal cord compression. Best outcomes are seen when both are treated.
How common is NPH?
It is impossible to know of how common this syndrome is because the symptoms of NPH can be caused by other conditions and NPH can occur along with other illnesses. However, it is estimated that about two to five percent of patients with dementia have NPH.
With the dramatic aging of the population, NPH must be considered a common and important problem, particularly because of its potential reversibility. One shunt valve manufacturer has estimated that there are about 1.3 million patients per year in North America who are potential candidates for shunting (Codman, written communication, 2005).
How is NPH treated?
There are currently no drug or therapy treatments that seem to be effective in the treatment of NPH. For now, NPH is a surgical disease.
- Shunting: A drainage tube is placed into the ventricles of the brain and connected to a valve. The valve is then connected to more tubing that drains into another part of the body, most commonly the abdominal cavity or the bloodstream. The procedure takes 60 to 90 minutes. Programmable valves on the shunt allow the drainage to be adjusted slowly to avoid bleeding in the brain. The adjustments are made after surgery in the office using a magnet.
- Endoscopic third ventriculostomy (ETV): In a small percentage of patients with NPH (less than 10 percent), there is a blockage of the normal pathway through which CSF flows. In such patients, an alternative pathway can be created through an endoscope. This procedure takes 15 to 60 minutes.
What is the likelihood of success?
In general, walking improves, although thinking does not to the same extent. Previous studies estimate that between 45 and 80 percent of people gain significant improvement from surgery. Risks of surgery are about 15 percent.
In our clinic, we evaluate many factors and try and estimate the risks and benefits of surgery for each of our patients individually, to help them and their families make an informed decision about whether or not to proceed with surgery. If someone does not respond to shunting, it is sometimes unclear whether this is because they never had the syndrome in the first place, the shunt was placed too late to help, or there is a malfunction of the shunt system.
How to schedule an appointment
Appointments can be scheduled Monday through Friday, 8:30 a.m. - 4:30 p.m. by calling (248) 325-0019 or email, [email protected].
Prior to scheduling an appointment in our NPH clinic, we request information that can assist in your diagnosis and treatment.
If you are not already a Henry Ford patient, we will need:
- Copies of clinic visits with your primary care physician
- Copies of clinic visits with your neurologist if you have seen one
- Copies of any hospital records relating to your diagnosis
- Results of any recent blood testing
- Written reports and copies of MRI's and/or CT's of the brain or spine with the raw image
If you are unable to get copies of these records, please contact the clinic for a release form and we will get these records on your behalf.
When you schedule your appointment, it is helpful to have the following:
- Your medical record number
- Who referred you to our clinic
- Your primary care physician's name
- Your neurologist's name if you have seen one
- A list of your medications
- Dates of any MRI's or CT scans
Our goal is to provide a comprehensive evaluation to diagnose other potential causes of symptoms and provide patients and their families with as much information as we can to help them make an informed decision about whether surgery is right for them.
For those who decide to go forward with surgery, we provide the best and most compassionate surgical and postsurgical care possible. For those who do not decide to proceed with surgery, we help coordinate care and obtain resources for patients and their families. All care is coordinated with the patient's other physicians.
Our team consists of neurosurgeons, neurologists, audiologists, neuroradiologists, physical therapists and nurses. We hold weekly multidisciplinary conferences to which the patient's referring physician is invited to participate by phone or in person.
NPH patient testimonials
L. Banerian (niece of patient)
"We really liked the team approach with the specialists and the neurosurgeon collaborating. The one thing that stood our for us during this experience was the coordination of care."
C. Cohen (patient)
"After surgery I began improving and now at 7 weeks after surgery I feel great. My walk and communication skills have greatly improved. One of the nicest features of Dr. Schwalb's team was having a case manager who at all times I was able to call for any reason what so ever."
"I feel very lucky and thank Dr.Schwalb and his team of professionals. They were understanding, patient and most skillful in their attention to me. I would highly recommend Henry Ford Hospital and Dr. Schwalb."
J. Henson (shunt patient)
"I was in trouble and since my shunt I am able to do almost everything again. My balance is good and I feel like I can do things and go places again. My experience has been excellent and I would recommend these doctors to anyone who has this problem."