Normal Pressure Hydrocephalus (NPH)
What is normal pressure hydrocephalus (NPH)?
Normal pressure hydrocephalus (NPH) is a condition that’s caused by an abnormal buildup of cerebrospinal fluid in the ventricles (cavities or spaces) of your brain. Cerebrospinal fluid is a clear liquid that circulates around your brain and spinal cord, cushioning and protecting them from damage. When people have NPH, they have an excess of cerebrospinal fluid because their bodies can’t properly drain and absorb the fluid. This fluid buildup can harm your brain.
The difference between NPH and other forms of hydrocephalus is that even though there’s a larger than normal amount of CSF, the pressure inside the ventricles remains the same. This buildup of fluid causes symptoms to happen over time.
Who gets normal pressure hydrocephalus (NPH)?
NPH most often occurs in people over age 60.
How common is normal pressure hydrocephalus (NPH)?
It’s difficult to know how many people actually have normal pressure hydrocephalus because its symptoms are similar to other diseases, such as Alzheimer’s or Parkinson’s disease, or even the natural aging process itself. However, it’s estimated that as many as 10%of people with dementia attributed to other disorders may actually have NPH.
Symptoms and Causes
What causes normal pressure hydrocephalus (NPH)?
The exact cause of NPH isn’t clear. In most cases, the cause of the buildup of cerebrospinal fluid (CSF) is unknown. However, in some cases, NPH can occur as a result of other conditions that affect your brain, including:
What are the symptoms of normal pressure hydrocephalus (NPH)?
There are three classic symptoms of normal pressure hydrocephalus:
- Difficulty walking. This problem can be mild or severe. In many cases, people with NPH have trouble picking up their feet. Some describe it as feeling like their feet are stuck to the floor. This can lead to a shuffling walk and problems going up stairs and over curbs. It also increases your risk of falling.
- Dementia. This often involves confusion, short-term memory loss/forgetfulness, trouble paying attention, changes in mood and a lack of interest in daily activities.
- Problems with bladder control. Problems include urinary incontinence (the inability to hold pee), frequent urination and a strong feeling of needing to urinate.
Diagnosis and Tests
How is normal pressure hydrocephalus (NPH) diagnosed?
Diagnosis begins with a careful review of symptoms and medical history, as well as a physical exam. Other tests include:
- Imaging tests. Your provider will order a CT scan or MRI of your head to look for enlarged ventricles in your brain, if appropriate.
- Cerebrospinal fluid tests. These tests include a spinal tap and external lumbar drainage. During a spinal tap, your provider removes a small sample of cerebrospinal fluid and assesses you to see if the symptoms improve. During external lumbar drainage, they'll remove more cerebrospinal fluid through a special catheter (tube) over 36 hours to further see if symptoms improve dramatically and to test the potential benefit of implanting a shunt (see treatment).
- Gait analysis (walking). This is a timed walk test. You’re watched as you walk 10 meters (about 30 feet).
- Neuropsychological testing. This involves a series of assessments to determine if there’s a loss of brain function (including memory, concentration and problem-solving) due to NPH.
Management and Treatment
How is normal pressure hydrocephalus (NPH) treated?
Although there isn’t a cure for NPH, the symptoms can be managed through surgery. Surgery involves inserting a drainage system called a shunt. One end of the shunt, which is a long sturdy, flexible plastic tube, is placed into one of your brain’s ventricles. The other end is tunneled under your skin to another area of your body, usually the lower part of your abdomen.
The shunt allows the excess cerebrospinal fluid to drain from your brain and be absorbed back into your body. A valve in the shunt keeps the fluid flowing in the correct direction and at the right rate. The shunt remains in your body for the rest of your life.
What are the complications of treatment?
Complications of normal pressure hydrocephalus treatment are those associated with any surgical procedure. They include bleeding, infection and reaction to the anesthesia used during surgery. You might also experience mild abdominal pain. Seizures also may happen, as surgery on your brain can affect very sensitive areas of it. Fortunately, these complications aren’t common, and in most cases, can be successfully treated.
Is there any way to prevent normal pressure hydrocephalus (NPH)?
Right now, there’s no known way to prevent NPH. However, getting treatment as soon as symptoms appear can improve those symptoms and increase the chance for a full or partial recovery.
Outlook / Prognosis
What is the outlook for people with normal pressure hydrocephalus (NPH)?
The chance of a good recovery from NPH is more likely if you’re diagnosed and treated in the early stages. Some people don’t need shunt surgery because their symptoms aren’t severe enough to affect daily life. People who don’t need surgery should continue to have check-ups with their doctor to monitor the symptoms. If your symptoms worsen, your doctor may recommend the surgery. Those who receive surgery often find that their symptoms are manageable.
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