Hydrocephalus is defined as a condition which is mainly characterized by excessive accumulation of fluid in the brain.Hydrocephalus can be classified as congenital or acquired. The indication of hydrocephalus in children and infants is rapid increase circumference of head or an unusual increase in head size. Hydrocephalus is mainly derived from the Greek words “hydro” which means water and “cephalus” means head. Hydrocephalus is a condition in which there is excessive accumulation of fluid in the brain. Although hydrocephalus was once known as “water on the brain,””water actually means cerebrospinal fluid (CSF) — It is a clear fluid that mainly surrounds the brain and spinal cord.Due to the excessive accumulation of CSF there is abnormal widening of spaces in the brain called ventricles. This widening creates harmful pressure on the tissues of the brain.
The ventricular system is made up of four ventricles which are connected by narrow passages.. Normally, CSF flows through these ventricles, exits into cisterns, at the base of the brain, bathes the surfaces of the brain and spinal cord, and then reabsorbs into the bloodstream. CSF performs many functions
1) It act as a cushion or “shock absorber”
2)It helps to deliver nutrients to the brain and remove wastes from body
3)It helps to maintain flow between the cranium and spine and compensate for changes in intracranial blood volume (the amount of blood within the brain). The balance between production and absorption of CSF is critically important. Because CSF is made continuously, medical conditions that block its normal flow or absorption will result in an over-accumulation of CSF. The resulting pressure of the fluid against brain tissue is what causes hydrocephalus.
TYPES OF HYDROCEPHALUS–
Hydrocephalus may be classified as congenital or acquired.
Congenital hydrocephalus is mainly present at birth and it may be caused by events or influences that occur during fetal development, or genetic abnormalities.
Acquired hydrocephalus develops at the time of birth or after sometime. This type of hydrocephalus can affect individuals of all ages and may be caused by injury or disease.
Hydrocephalus can also be divided into communicating or non-communicating
Communicating hydrocephalus occurs when there is blockage in the flow of CSF after it exits the ventricles. This form is called communicating because the CSF can still flow between the ventricles, which remain open.
Non-communicating hydrocephalus – also called “obstructive” hydrocephalus – It mainly occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles. One of the most common causes of hydrocephalus is “aqueductal stenosis.” In this case, hydrocephalus results from a narrowing of the aqueduct of Sylvius, a small passage between the third and fourth ventricles in the middle of the brain.
Other forms of hydrocephalus are hydrocephalus ex-vacuo and normal pressure hydrocephalus.
Hydrocephalus ex-vacuo occurs when there is stroke or some traumatic injury to the brain and causes damage . In these cases, brain tissue may actually shrink. Normal pressure hydrocephalus can happen to people at any age, but it is most common among the elderly. It may be due to sub arachnoid hemorrhage, head trauma, infection, tumor, or complications of surgery.