Hydro Facts

Here are a few facts about Hydrocephalus:

  • Hydrocephalus is one of the most common birth defects, each year one out of every 500 births results in hydrocephalus.
  • Another 6,000 children annually develop hydrocephalus during the first 2 years of life.
  • Brain injury occurs every 15 seconds in this country – and in some cases leads to the development of hydrocephalus.
  • There are approximately 75,000 discharges a year from hospitals in the U.S. with a diagnosis of hydrocephalus.
  • More than 50% of hydrocephalus cases are congenital.
  • 70-90% of children born with spina bifida also develop hydrocephalus.
  • CSF shunting procedures account for approximately $100 million health care spending in the United States alone – half of this amount is spent on shunt revisions.
  • In the past 25+ years, death rates associated with hydrocephalus have decreased from 54% to 5%, and the occurrence of intellectual disability has decreased from 62% to 30%.
  • Normal Pressure Hydrocephalus affects adults and can cause dementia, difficulty in walking and, urinary incontinence.
  • No statistics are kept (by our government), for those who develop.
  • Approximately 1 million people have hydrocephalus in the US.
  • There are believed to be 180 different causes.
  • There is no cure and very little research. The NIH spends 60 cents per person with hydrocephalus per year compared to $300 per person per year with Juvenile Diabetes though the prevalence of each is the same.
  • The standard treatment, a shunt, was developed in 1956 and has a 50% failure rate after just two years which is the reason so many have to have multiple brain surgeries just to stay alive.
  • 60% of children with hydrocephalus are not independent as adults and require assistance.
  • 50% of children with hydrocephalus score 80 or below on standardized intelligence tests.
  • It costs the United States $1 billion per year in health care costs to treat hydrocephalus.

So what is hydro?

Hydrocephalus is caused by a build-up of fluid inside the skull, which can increase pressure and cause damage to the brain. Both the brain and spine are surrounded by cerebrospinal fluid (CSF), which is essential for cushioning the brain, providing nutrients and removing waste products.

Hydrocephalus stems from many causes: if the flow of CSF is blocked, if the body produces too much CSF, or if there is a problem with the arachnoid villi which stops CSF being absorbed into the blood.

Types of hydrocephalus

5 main types of hydrocephalus:

  • Communicating hydrocephalus occurs despite the fact that there is no obvious blockage or obstruction in the flow of CSF. The term non-obstructive hydrocephalus is also used. It occurs when the reabsorption of the CSF into the bloodstream is impaired, resulting in increased CSF pressure and enlarged ventricles.
  • Non-communicating hydrocephalus occurs when there is a blockage in the flow of CSF. It is also known as obstructive hydrocephalus.
  • Hydrocephalus ex vacuo is the result of the ventricles enlarging to compensate for loss of brain tissue. This can happen as a result of another form of acquired brain injury, such as a stroke or traumatic injury.
  • Arrested hydrocephalus can occur in people who have a minor blockage in the CSF flow. The person may suffer no effects because the CSF production is balanced by absorption and so pressure is normal. However, if the balance is disrupted spontaneously, or after a minor head injury, then the resulting increase in CSF pressure is called arrested hydrocephalus.
  • Normal pressure hydrocephalus (NPH) affects older people (average age 70-75) and is often categorized as a form of dementia. This type of hydrocephalus can be difficult to diagnose because it develops over a long period of time so the fluid pressure in the brain may not appear to be high. It can develop after brain injury but in most cases the cause is unknown.

Causes of hydrocephalus

The different types of hydrocephalus can be congenital, acquired or idiopathic.

  • Congenital hydrocephalus – When hydrocephalus is caused by congenital birth defects the symptoms normally present themselves in childhood. However, they may not appear until adulthood in some cases.
  • Acquired hydrocephalus – Hydrocephalus can be acquired at any stage of life due to head injuries, strokes, tumours, meningitis, hemorrhages and other forms of ABI.
  • Idiopathic hydrocephalus – This means that there is no known cause and many cases of hydrocephalus, at any stage of life, appear despite no apparent obstruction or impairment of CSF reabsorption.

Symptoms of hydrocephalus

Acquired and idiopathic forms of hydrocephalus can occur at any time in life and typical symptoms include:

  • Headaches
  • Neck pain
  • Nausea
  • Vomiting
  • Drowsiness
  • Confusion
  • Poor co-ordination
  • Blurred or double vision
  • Difficulty walking
  • Bladder and/or bowel incontinence


There are a number of different treatments and diagnostic tests for hydrocephalus. MRI or CT scans can show signs CSF build-up, such as enlarged ventricles. Brain scans can also help doctors determine the cause of hydrocephalus, and rule out other possible reasons for the symptoms.
Other commonly used diagnostic tests include eye tests to check vision and look for swelling behind the eyes. Lumbar punctures are also performed to examine the CSF and check pressure levels.


Initial treatment for hydrocephalus focuses on reducing pressure on the brain, and restoring the normal flow of cerebrospinal fluid.

A shunt is usually used to drain excess CSF from the brain. A shunt is a small tube that is implanted in the brain and runs to another part of the body, usually the abdomen, where the CSF can be absorbed into the blood stream.

There are a number of other treatments that doctors may explore. You can find out more about treatments for hydrocephalus by browsing the links below or contacting the Headway helpline.
Long term effects

If hydrocephalus causes damage to the brain, the symptoms may be similar to other types of acquired brain injury. Rehabilitation may be beneficial to help regain independence and maximize recovery.