Normal Pressure Hydrocephalus

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The brain and spinal cord are surrounded by a clear fluid known as cerebrospinal fluid (CSF). This fluid is made and stored in cavities in the brain called ventricles. CSF is critical to the proper function of the brain and spinal cord. It remains in a closed-circuit loop to protect the brain and spinal cord from infection. CSF also supplies the brain and spinal cord with nutrients and removes some of the waste products that may accumulate over time. Patients quickly perceive the slightest change in CSF pressure.

Hydrocephalus is the condition in which there is too much CSF in the ventricles caused by a malfunction in the draining and absorbing systems. When too much fluid collects in the ventricles they will enlarge to accommodate the extra fluid. This enlargement puts pressure on the brain causing numerous symptoms.

Normal pressure hydrocephalus (NPH) is a type of hydrocephalus that occurs mainly in adults over the age of 60. NPH develops slowly over time; therefore changes are subtle or less noticeable. The fluid pressure builds up gradually in the ventricles which causes pressure to increase in the brain.

Causes of Normal Pressure Hydrocephalus

The cause of normal pressure hydrocephalus is often unknown. However, there are some known conditions that can increase the likelihood of NPH including:

  • Head trauma or injury
  • Subdural hematoma (bleeding around the brain)
  • Stroke
  • Meningitis
  • Brain tumor
  • Surgical complications

Symptoms of Normal Pressure Hydrocephalus

The areas in the brain most affected by NPH are those that control the legs, bladder and cognitive processes (such as short term memory loss, reasoning, problem solving and speech). Other symptoms of NPH include, but are not limited to:

  • Abnormal walk or gait; shuffling steps
  • Difficulty walking
  • Urinary incontinence (inability to hold urine)
  • Urinary urgency
  • Rarely, bowel incontinence
  • Dementia 
  • Apathy and withdrawal
  • Unsteadiness
  • Sudden falls

More acute symptoms related to increased pressure in the brain include:

  • Headache
  • Nausea
  • Difficulty focusing eyes

Diagnosing NPH

Experts agree that NPH is highly misdiagnosed as Alzheimer’s or Parkinson’s Disease. After an accurate diagnosis, NPH can be reversed with appropriate treatment. Your neurosurgeon will recommend imaging tests to accurately diagnose NPH. The tests most often used in determining NPH are:

  • CT scan of the head 
  • MRI scan of the head
  • Lumbar puncture (spinal tap) to measure the pressure of the spinal fluid

If the lumbar puncture temporarily relieves the symptoms, then it is often inferred that the placement of a shunt to help drain extra CSF will be helpful.

Treatment of Normal Pressure Hydrocephalus

Normal pressure hydrocephalus is generally a long-term condition. Patients diagnosed with NPH can often obtain substantial relief from the placement of a surgical shunt. The shunt will aid in the draining of excess CSF and keep the symptoms manageable. 

Patients with NPH will always need to be under the care of an experienced physician. Your doctor will focus on optimizing your quality of life and safety and help to manage challenges associated with NPH.  

What is a Shunt?

A shunt is a thin tube that is implanted in the brain by a neurosurgeon. The shunt drains excess CSF away from the brain to another part of the body. The shunt utilizes a valve mechanism that opens to release fluid when the pressure increases.