Definition

Normal Pressure Hydrocephalus (NPH) is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain that causes them to enlarge, increasing pressure on the rest of the brain. The enlarged ventricles seen in NPH are similar to the hydrocephalus seen in children but the causes, symptoms, and diagnosis are somewhat different.


CT of a patient after VPS placement. Note enlarged ventricles.

Causes

  • Age
  • Head trauma
  • Subarachnoid hemorrhage
  • Tumor
  • Infection
  • Complications of brain surgery
  • Idiopathic (no known cause)

Risk Factors

Risk factors are things associated with an increased chance of developing a disease or condition

  • Bleeding from a blood vessel or brain aneurysm
  • Tumor or cyst in the brain
  • Head injury
  • History of meningitis or other central nervous system infection
  • History of brain surgery

Symptoms

NPH has a classic triad of symptoms:

  • Gait disturbances – feet appear to stick to the ground. The short shuffling steps and stooped, forward-leaning posture may resemble that of Parkinson’s Disease, but there is no rigidity or tremor.
  • Memory problems – often misdiagnosed as early Alzheimer’s Disease or other dementias
  • Urinary incontinence – tends to appear later in the disease course

Diagnosis

Lumbar puncture – improvement in the patient’s symptoms generally indicates a good chance of improvement with shunting

  • CT scan
  • MRI scan

Treatment

Surgical placement of a ventriculoperitoneal shunt (VPS) to drain off excess CSF is the main treatment. The ventricles generally decrease in size quickly, but only about 20 percent of patients show improvement in their symptoms.

Prevention

There is no known method of preventing NPH. Early, accurate diagnosis and treatment can prevent symptoms from getting worse and essentially cure some patients.

Case study

A 67-year-old man with a history of progressively worsening memory and gait problems along with urinary incontinence was evaluated for VPS placement. He tolerated the procedure well and was already showing signs of improvement in all three symptoms at his post-operative visit. His memory continued to improve, enough so that he was able to return to work after a few months. He also reported almost complete resolution of his gait disturbances and urinary incontinence.

Disclaimer

Content generated and provided by Joshua B. Bederson, MD, Professor and Chairman of the Department of Neurosurgery at The Mount Sinai Health System. Some of the information contained in this article was adapted from the National Institutes of Health. Last reviewed June 2011 by the Department of Neurosurgery at The Mount Sinai Health System.

If you want to learn more about normal pressure hydrocephalus and its treatment call the Mount Sinai Department of Neurosurgery at 212-241-2377.

Image used with permission from Joshua B. Bederson, MD