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Normal Pressure Hydrocephalus

Normal pressure hydrocephalus is a condition that results when the balance of cerebrospinal fluid (CSF) within the brain is disrupted. It can also occur when the body fails to absorb CSF properly. CSF provides a number of important functions. Distributing nutrients to the brain is a primary function of CSF, as well as forming a cushion to protect the brain inside the skull.

Anatomy of the brain

Inside your brain are four ventricles. CSF flows through the ventricles by way of channels that connect one ventricle to another. Eventually, the CSF is absorbed into your bloodstream. In order to maintain normal pressure inside the skull the production, flow and absorption of CSF must be kept in balance.

Normal pressure hydrocephalus

When the balance of CSF is disrupted, it may cause normal pressure hydrocephalus, seen most often in older people. Normal pressure hydrocephalus may be the result of a traumatic fall or injury or illness. In most cases, the cause is unknown.


Symptoms of normal pressure hydrocephalus may include:

  • Gait and balance problems
  • Urinary incontinence
  • Dementia

Any of the above symptoms can be indicative of a wide range of diseases common in the aging population. Our team of specialists is trained to rule out other disorders possibly causing these symptoms, including Parkinson’s disease and Alzheimer’s disease.

Diagnostic evaluation

In order to properly diagnose normal pressure hydrocephalus, your doctor will perform the following:

  • A meticulous clinical exam and thorough medical history to rule out other potential disorders or diseases.
  • An imaging study of the brain, usually by MRI, to examine the ventricles. In older people, who are found not to have normal pressure hydrocephalus, the ventricles can also be enlarged. The imaging scan is used in confirming the diagnosis, or ruling out other disorders.
  • A consultation with other highly-trained specialists in this field, including balance/gait and neuromuscular specialists.

Confirmation of the diagnosis

If the doctor continues to suspect a diagnosis of normal pressure hydrocephalus, he or she will probably order a spinal tap. This spinal tap will measure the pressure of CSF using a manometer, a measurement tool. This procedure can be done in a one-time large volume spinal tap to remove the excess fluid, or over a period of 3 days in the hospital with careful monitoring by the doctors.

This careful monitoring is part of the treatment program our specialists have created. The pressure created by the excess CSF will be relieved by either of these treatment methods. If patients’ symptoms improve, the diagnosis of hydrocephalus is confirmed.

If patients’ symptoms do not improve, then hydrocephalus is no longer suspected as the cause. However, in some cases, these patients may have hydrocephalus, but will not find relief from drainage of CSF.

Surgical treatment method

If drainage of CSF by a large volume spinal tap or insertion of a lumbar catheter improves a patient’s symptoms, a diagnosis of hydrocephalus is confirmed, and your doctor will suggest long-term solutions.

Your neurosurgeon will propose placing a shunt to drain the excess CSF from the brain into another part of the body. These shunts have been specially developed by our doctors, who hold patents on these specialized valves. They are titrated and adjustable, so the exact amount of CSF needed to be drained can be personalized for each patient. The placement of the shunt will be recommended by the neurosurgeon based on your particular case. The fluid may be redirected by the following methods:

  • Ventricular shunt- the fluid will be drained into the peritoneal cavity or belly
  • Lumbar shunt- the fluid will be drained into the peritoneal cavity or belly
  • Right Atrium shunt- the fluid will be drained into your heart

The goal of the shunt is to continuously drain the correct amount of CSF so the patient has relief from all hydrocephalus symptoms.

Read about Frequently Asked Questions about hydrocephalus

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Adult Neurology: 410-955-9441
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