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Hydrocephalus: Frequently Asked Questions

What is Hydrocephalus?

Learn more about hydrocephalus.

What is Normal Pressure Hydrocephalus?
Normal pressure hydrocephalus (NPH) is an accumulation of CSF that causes the ventricles in the brain to become enlarged, sometimes with little or intermittent increases in intracranial pressure (ICP). It is most commonly seen in older adults, and is accompanied by some or all of the following symptoms: gait disturbance, mild dementia and impaired bladder control.

What Causes Normal Pressure Hydrocephalus?
The majority of cases of NPH have no known cause. It can develop as the result of a head injury, cranial surgery, subarachnoid hemorrhage, tumor or cysts, as well as subdural hematomas, , meningitis and other brain infections.

What are the Symptoms of Hydrocephalus?
NPH is usually characterized by a triad of symptoms: complaints of gait disturbance (difficulty walking), mild dementia and impaired bladder control. These symptoms may not occur all at the same time, and sometimes only one or two symptoms are present. The triad of symptoms is often associated with the aging process and a majority of the NPH population is older than 60 years. The cognitive deficits of NPH can resemble those associated with Alzheimer’s and the gait disturbances of NPH can look similar to those of Parkinson’s disease. In some cases NPH can occur in combination with these diseases. Symptoms of hydrocephalus seem to progress with time, but the rate is variable. As a general rule, the earlier the diagnosis, the better the chance for successful treatment; however some patients who have had symptoms for years may improve with treatment.

How is Normal Pressure Hydrocephalus Diagnosed?

  • Brain images to detect enlarged ventricles
    • MRI
    • CT or CAT scan
    • Lumbar or spinal tap
    • External lumber drainage
    • Measurement of CSF outflow resistance

What Treatment is Available?

  • A collection catheter situated within the cerebral ventricles
  • A valve mechanism to control how much CFS flows


Who is a Likely Candidate for Shunting?
The answer to this question is still uncertain. No one single factor is reliable in predicting success from implantation of a shunt. The following findings are generally associated with a better outcome following shunt placement:


Although everyone hopes for a complete recovery, it is not often seen. Many individuals and their families are satisfied when shunt surgery results in reduced disability or dependence than he or she had before surgery, or prevention of further neurological deterioration. People with NPH, their families and their physicians need to be supportive and hopeful, but they should also know the possible complications, risks and realities of shunt implantation.

What does a Shunt Operation Entail?
The surgical procedure to implant a shunt usually requires less than an hour in the operating room. The patient generally stays under careful neurological observation for the first 24 hours following the procedure. Patients generally stay in the hospital from one to seven days. Follow-up visits will be necessary to check post-operative status and resolution of symptoms. After surgery, physical therapy, occupational therapy and other rehabilitation strategies may be advised to help patients attain as much resolution of symptoms as possible.

How Successful is Shunting?
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. Other factors that affect the outcome after shunt surgery are the presence of other neurological or medical conditions. The more symptoms are due to NPH, rather than the associated conditions, the greater the likelihood of successful recovery after shunting.

What are the Complications and Risks Involved with Shunting?
The potential complications of shunt surgery include those related to the actual operation, as well as those that may occur days to years later. One of the most common problems with shunt systems is that they can become obstructed; however it can usually be easily fixed and rarely results in serious problems, although further surgery may be necessary. Other common complications include: shunt malfunction; infection at the site of the surgical wound, the shunt or the CSF (meningitis); bleeding into the brain or ventricles; or a seizure. One of the more serious complications that can occur following the insertion of a shunt is a subdural hematoma (blood clot). This risk occurs approximately 5 to 10 percent of the time. Given the potential complications, individuals and their families need to assess their own situation to determine if the possible benefits of surgery outweigh the possible risks.

How can I consult a Johns Hopkins specialist for assessment of possible NPH?
There are several neurologic conditions that can mimic NPH. Obtaining a CT or MRI of the Brain is helpful in narrowing the possibilities and is often the first step in the diagnosis. If the symptoms and scans are consistent with NPH your primary care physician or neurologist can refer you to our center for further assessment. To arrange for a personal appointment to discuss hydrocephalus diagnosis and treatment options with a specialist at the Johns Hopkins Normal Pressure Hydrocephalus Center, please call 410-955-7482. We will need you to fill a detailed questionnaire and review your medical notes and actual scans before your appointment, for optimal assessment at your clinic visit. More information can also be found at


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