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Normal–Pressure Hydrocephalus

By

Juebin Huang

, MD, PhD, Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center

Last full review/revision Apr 2020| Content last modified Apr 2020
Click here for the Professional Version
Topic Resources

Normal-pressure hydrocephalus consists of difficulty walking, urinary incontinence, and dementia due to an increase in the fluid that normally surrounds the brain.

  • Usually, the main symptoms of normal-pressure hydrocephalus are general unsteadiness and loss of balance, and the feet may seem to stick to the floor.

  • Dementia may not develop until late in the disorder.

  • Doctors usually do magnetic resonance imaging to check for excess fluid around the brain and do a spinal tap or place a temporary drain into the spinal cord to remove any excess fluid.

  • Placing a piece of plastic tubing (a shunt) in the brain to drain the excess fluid may significantly lessen some symptoms, but it may benefit mental function less.

Normally, the fluid that surrounds the brain and protects it from injury (cerebrospinal fluid) is continuously produced in the spaces within the brain (ventricles), circulates in and around the brain, and is reabsorbed. Normal-pressure hydrocephalus is thought to occur when this fluid is not reabsorbed normally, causing it to accumulate. The amount of fluid in the ventricles increases and the brain is then pushed outward.

Symptoms

Usually, the main symptoms of normal-pressure hydrocephalus are general unsteadiness and loss of balance. People typically have an abnormally slow, unsteady, wide-legged walk. The feet may seem to stick to the floor (called a magnetic gait). People also have urinary incontinence and a tendency to fall.

Dementia may not develop until late in the disorder. Often, the first signs of dementia are difficulty planning, organizing, putting ideas or doing actions for a task in the right order (sequencing), thinking abstractly, and paying attention. Memory tends to be lost later.

Diagnosis

  • A doctor's evaluation

  • Brain imaging, usually magnetic resonance imaging

  • Removal of cerebrospinal fluid

Doctors may suspect normal-pressure hydrocephalus when people have the three typical symptoms:

  • Difficulty walking

  • Urinary incontinence

  • Dementia

However, the diagnosis of normal-pressure hydrocephalus cannot be based on symptoms alone, particularly in older people. Other dementias can cause similar symptoms, and in older people, many conditions can make walking difficult or cause urinary incontinence.

Diagnosis of dementia

Doctors base a diagnosis of dementia on the following:

  • Symptoms, which are identified by asking the person and family members or other caregivers questions

  • Results of a physical examination, including a neurologic examination

  • Results of a mental status test

  • Results of additional tests, such as computed tomography (CT) or magnetic resonance imaging (MRI)

Mental status testing, consisting of simple questions and tasks, helps doctors determine whether people have dementia.

Sometimes more detailed testing (called neuropsychologic testing) is needed. This testing covers all the main areas of mental function, including mood, and usually takes 1 to 3 hours. This testing helps doctors distinguish dementia from other conditions that can cause similar symptoms, such as age-associated memory impairment, mild cognitive impairment, and depression.

Information from the above sources can usually help doctors rule out delirium as the cause of symptoms (see table Comparing Delirium and Dementia). Doing so is essential because delirium, unlike dementia, can often be reversed if promptly treated. Differences between the two include the following:

  • Dementia affects mainly memory, and delirium affects mainly attention.

  • Dementia typically begins gradually and has no definite beginning point. Delirium begins suddenly and often has a definite beginning point.

Diagnosis of normal-pressure hydrocephalus

Brain imaging, usually magnetic resonance imaging (MRI) is done to check for excess cerebrospinal fluid. Finding excess fluid and other characteristic changes in the brain supports the diagnosis of normal-pressure hydrocephalus but does not confirm it.

To help with the diagnosis, doctors do a spinal tap (lumbar puncture) or place a temporary drain into the spinal cord to remove excess cerebrospinal fluid. If these procedures relieve symptoms, usually by improving gait, normal-pressure hydrocephalus is more likely, and treatment is more likely to be effective.

Treatment

  • A shunt in the ventricles of the brain

Treatment of normal-pressure hydrocephalus consists of placing a piece of plastic tubing (a shunt) in the ventricles of the brain and running it under the skin, usually to the abdomen (ventriculoperitoneal shunting). Cerebrospinal fluid is then drained away from the brain. The effects of this treatment may not be evident for several hours. This procedure may significantly improve the ability to walk and function and may lessen incontinence. However, mental function improves less and in fewer people. Thus, early diagnosis is important, so that people can be treated before dementia develops.

Other treatments are similar to treatments for other types of dementia.

Safety and supportive measures

Generally, the environment should be bright, cheerful, safe, stable, and designed to help with orientation. Some stimulation, such as a radio or television, is helpful, but excessive stimulation should be avoided.

Structure and routine help people with dementia stay oriented and give them a sense of security and stability. Any change in surroundings, routines, or caregivers should be explained to people clearly and simply.

Following a daily routine for tasks such as bathing, eating, and sleeping helps people with dementia remember. Following a regular routine at bedtime may help them sleep better.

Activities scheduled on a regular basis can help people feel independent and needed by focusing their attention on pleasurable or useful tasks. Such activities should include physical and mental activities. Activities should be broken down in small parts or simplified as the dementia worsens.

Care for caregivers

Caring for people with dementia is stressful and demanding, and caregivers may become depressed and exhausted, often neglecting their own mental and physical health. The following measures can help caregivers (see table Caring for Caregivers):

  • Learning about how to effectively meet the needs of people with dementia and what to expect from them: Caregivers can get this information from nurses, social workers, organizations, and published and online materials.

  • Seeking help when it is needed: Caregivers can talk to social workers (including those in the local community hospital) about appropriate sources of help, such as day-care programs, visits by home nurses, part-time or full-time housekeeping assistance, and live-in assistance. Counseling and support groups can also help.

  • Caring for self: Caregivers need to remember to take care of themselves. They should not given up their friends, hobbies, and activities.

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