Hydrocephalus is an irregular collection of cerebrospinal fluid (CSF) within the ventricles, which are fluid filled cavities in the brain.  This fluid surrounds the brain and spinal cord and cushions it against injury.  It also contains nutrients that are important for normal brain function. Under normal conditions, a delicate balance exists between the production, circulation, and absorption levels of cerebrospinal fluid in the cavities of the brain known as "ventricles." Hydrocephalus develops when cerebrospinal fluid can't flow through the ventricular system, or when absorption into the bloodstream isn't the same as the amount of cerebrospinal fluid produced.

There are two types of hydrocephalus: obstructive and communicating.  Both types of hydrocephalus can cause increased pressure within the brain.

Obstructive hydrocephalus occurs when the flow of the spinal fluid is blocked by something, like a tumor.

Communicating hydrocephalus occurs when the brain is not able to absorb the spinal fluid correctly causing too much fluid to collect.

Some older patients can have a type of hydrocephalus known as Normal Pressure Hydrocephalus (NPH).  With normal pressure hydrocephalus, there is an increased amount of fluid within the brain but no increase in pressure.  This type of hydrocephalus usually occurs in older adults.  Symptoms of NPH can be characterized by the gradual onset of three symptoms, usually in this order:

  • Gait disturbance (difficulty walking) in the form of small shuffling steps, a tendency to fall, a feeling of heavy feet, or difficulty using stairs
  • Urinary incontinence (impaired bladder control) in the form of a frequent or urgent need to urinate, or the loss of control to hold back urine
  • Mild dementia (cognitive impairments) in the form of forgetfulness, short-term memory loss, loss of interest in activities, or mood changes

Diagnosis of Hydrocephalus

The diagnosis of hydrocephalus is typically performed with a CT Scan and MRI of the head/brain.  These tests can show the size and shape of the ventricles in the brain as well as any abnormalities caused by hydrocephalus.

The most common surgical hydrocephalus treatment option is the insertion of a shunt.