Hydrocephalus can be classified as
- CSF circulation via the ventricles of the brain is intact, but the absorption into the venous bloodflow is blocked
and Non-communicating or Obstructive
- Circulation of CSF is blocked somewhere between the lateral, third and/or fourth ventricles.
Other classifications are:
Congenital hydrocephalus is present at birth. Children born with hydrocephalus may be diagnosed during the pregnancy or at birth. Often children born with hydrocephalus do have an abnormal head circumference. Congenital hydrocephalus can occur together with diseases like:
- Spina Bifida
- Dandy-Walker syndrome
- Aqueduct Stenosis
Acquired hydrocephalus can occur at any stage in human lifetime as a consequence of an accident, surgery, cerebral bleeding, tumor, meningitis and/or others.
A special form of acquired hydrocephalus is the so-called Normal Pressure Hydrocephalus (NPH).
Normal pressure hydrocephalus describes a neurologic condition of ventricular dilatation in the absence of increased CSF pressure. NPH is characterized by a triad of symptoms: gait impairment (a broad-based, shuffling, magnetic gait), urinary incontinence, and a form of dementia.
The importance of this diagnosis lies in the fact that it is a potentially reversible cause of dementia.
The cause of NPH is often unclear. These cases are called “primary” or “idiopathic” NPH (iNPH). The remaining cases are so-called secondary NPH (sNPH). The cause of the disease is known and is secondary to either a head injury, subarachnoid bleeding, meningitis or a tumor.
NPH is a disease of the elderly population, with an increasing incidence beginning between the ages of 65 and 70 years.