Normal pressure hydrocephalus (NPH) is a neurological condition caused by a buildup of cerebrospinal fluid in the ventricles.
The buildup of fluid causes the ventricles to grow and affect nearby areas of the brain. This may cause symptoms such as cognitive decline, imbalance, and urinary incontinence.
Patients with NPH may be candidates for surgery that involves placing a shunt in the brain to divert fluid. The shunt may help to improve symptoms.
Normal pressure hydrocephalus, or NPH, is a brain disorder caused by a buildup of excess cerebrospinal fluid (CSF) in the ventricular system. The ventricular system consists of four ventricles — fluid-filled chambers in the center of the brain.
The body produces daily volumes of CSF — a clear, colorless fluid, mostly made of water — and it protects the brain and spinal cord. Excess fluid is typically absorbed back into the body. People with NPH produce a normal amount of CSF, but the excess fluid isn't absorbed properly, leading to excess fluid in the brain.
The excess fluid causes the ventricles to become enlarged, which puts pressure on nearby brain areas. This pressure may cause cognitive issues (dementia) and physical problems (loss of bladder control and trouble walking).
An estimated 800,000 Americans have NPH, but many go undiagnosed. Symptoms of NPH appear similar to other conditions like Alzheimer's disease or Parkinson's disease. NPH primarily affects older adults.
Symptoms of NPH typically appear gradually and worsen over time. Patients may benefit from shunt surgery, but not all are candidates.
According to the Hydrocephalus Association, an estimated 800,000 Americans have normal pressure hydrocephalus. However, only about 20% are diagnosed. NPH may be misdiagnosed as a different brain condition or normal aging, or people may be unknowingly living with it.
People may be born with NPH, but it typically develops over time. Most people diagnosed with NPH are 60 and older.
NPH is caused by a buildup of cerebrospinal fluid in the brain. In NPH, the cerebrospinal fluid is produced in normal amounts but is not properly absorbed.
In most cases of NPH, it's unknown why this happens. NPH without a known cause is called idiopathic NPH or primary NPH.
In other cases, NPH can occur after a brain injury, condition, or treatment. This condition is called secondary NPH.
Causes of secondary NPH include:
Some people with NPH may also have other brain conditions, such as Alzheimer's disease.
NPH typically presents in older adults, so people 60 and older are at greater risk.
People may also be at greater risk if they've had brain or skull injuries, infections, surgeries, or other related conditions.
Without proper diagnosis and treatment, NPH can have cognitive and physical effects.
You may have trouble with:
Normal pressure hydrocephalus has three common warning signs:
While these are the three most common symptoms of NPH, not every person will exhibit all of them. Walking issues are the most common warning sign.
Make an appointment with a neurologist if you are showing signs of normal pressure hydrocephalus. Testing can help determine whether the cause is NPH or another condition.
A neurologist can diagnose normal pressure hydrocephalus. Because NPH is similar to other disorders, it's best to visit a specialist with experience in diagnosing and treating it.
Neurologists will diagnose NPH using a combination of a physical exam, brain imaging studies, and other tests.
During your visit, the team will take your medical history. They will ask questions about your symptoms and how long you've had them. They will also ask about your health history, including any medical conditions you have and medications you take.
They may order imaging tests and other exams to diagnose or rule out NPH.
Because NPH is similar to other conditions, doctors typically will order tests to diagnose it or rule it out.
Imaging exams can show enlarged ventricles within the brain, indicating normal pressure hydrocephalus.
The most typical exam to diagnose NPH is an MRI. MRIs use a combination of radio waves and a powerful magnet to produce images of the brain.
Less commonly, a CT scan may be used. CT scans use x-ray technology to produce images of the brain.
In neuropsychological testing, patients are asked a series of questions and asked to perform some simple tasks. The results can help diagnose any cognitive issues and their severity.
A licensed physical therapist can evaluate a patient's walking ability to help determine the severity of their symptoms.
Doctors may order blood work to rule out other potential causes of patients' symptoms.
A lumbar puncture, or spinal tap, may help determine whether a patient with NPH is a good candidate for shunt surgery.
In a lumbar puncture, a doctor inserts a thin needle into the spine to collect up to 50 mL of cerebrospinal fluid.
The patient's symptoms are tested before and after the fluid removal. If their symptoms are temporarily improved after the procedure, it suggests they're a good candidate for shunt surgery.
Similar to lumbar puncture, external lumbar drainage can help determine if a patient is a good candidate for surgery.
In external lumbar drainage, a catheter (a thin, flexible tube) is inserted into the spine. The catheter periodically or continually drains cerebrospinal fluid over the course of several days.
The catheter mimics what a shunt would do. If a patient shows improvement with external lumbar drainage, they may be a good candidate for surgery. However, patients must remain in the hospital during external lumbar drainage.
NPH can cause cognitive and physical symptoms that interfere with daily life. Symptoms can range from mild to severe and worsen over time without treatment. People may have difficulty caring for themselves or living alone, especially if they have severe symptoms. In severe cases, NPH can be life-threatening.
Surgical placement of a shunt to divert excess fluid can potentially improve symptoms. Early, accurate diagnosis and timely treatment can lead to a better long-term prognosis.
The goal of treating NPH is to improve or control the symptoms. NPH is one of the only types of dementia that is potentially treatable.
There are currently no medicines or other nonsurgical treatments for NPH. The common treatment for NPH is surgery to place a shunt in the brain to divert excess fluid.
Not every patient is a candidate for shunt surgery. Patients whose symptoms respond well to lumbar puncture or external lumbar drainage are ideal candidates. Patients may not be candidates for surgery if they didn't respond well to those tests, if they have other health conditions, or if their overall health is poor.
The typical surgery for normal pressure hydrocephalus is shunt surgery. The surgery involves the use of catheters (tubes) and a valve to send excess fluid from the brain to another part of the body, where it can be absorbed.
A neurosurgeon performs the procedure, with a general surgeon assisting. The procedure takes about one hour. Once a shunt is in place, it is typically needed permanently.
Patients are typically in the hospital for one day after surgery. A longer stay may be necessary depending on your specific case.
Although a common procedure, shunt surgery contains a small risk of complications, including:
Better shunt technology has helped to improve success rates for shunt surgery, especially if presurgical screening indicates a positive response. Some people may make a full recovery, while others may see their symptoms improve significantly.
The biggest improvements typically come in gait and balance, but other symptoms also can improve.
Patients may see some improvements right away, but full improvement may take weeks to months.
Patients typically will spend at least one night in the hospital after shunt surgery. Some patients will need a longer stay.
The recovery period from shunt surgery can take weeks to months. Your neurosurgeon may recommend physical, occupational, and/or cognitive therapies to help you regain function.
You should see your neurosurgeon regularly for follow-up appointments and repeat imaging exams.
These visits help ensure that:
Living with a shunt is typically permanent. You should ask your surgeon about any activities to avoid after surgery.
The UPMC Department of Neurosurgery, part of the UPMC Neurological Institute, is a national leader in brain, skull base, and spinal disorders. At UPMC, you can expect:
By UPMC Editorial Staff. Last reviewed on 2025-05-02.
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