Hydrocephalus is an abnormal (excessive) accumulation of fluid in the head.
The fluid is called cerebrospinal fluid, commonly referred to as CSF. The CSF is located and produced within cavities of the brain called ventricles.
The function of CSF is to cushion the delicate brain and spinal cord tissue from injuries and maintain proper balance of nutrients around the central nervous system. When an imbalance arises and production exceeds reabsorption in the normal way, an excess of CSF builds up, resulting in the condition known as hydrocephalus. Left untreated, hydrocephalus will create increased pressure in the head and may result in brain damage, disability, or even death.
Normally, most of the CSF produced on a daily basis is absorbed into the blood stream. Every hour of every day, your body produces a certain amount of CSF, and that same amount is reabsorbed.
When an imbalance occurs, an excess of CSF builds up, resulting in the condition known as hydrocephalus. Left untreated, hydrocephalus will create increased pressure in the head and may result in brain damage, disability, or even death.
Role of CSF:
- Buoyancy: The actual mass of the brain (1400grams) suspended in CSF is equivalent to 25grams, which allows
the brain to maintain density and bloody supply.
- Brain Protection
- Chemical Stability (sink action)
- Transportation of metabolic active substances
CSF Physiology I:
Most CSF originates in the Choroid Plexus
Some is derived from the extracellular space.
CSF flows from the ventricles to the subarachnoid space.
Approximately half the CSF flows down the spinal canal and is absorbed there.
As it circulates over the cerebral hemispheres, it is absorbed into the sagittal sinus via the arachnoid villi and returns to the venous system.
Production of CSF is not stopped, even if ICP is slightly increased or if there is a blockage of the CSF Flow
In general, hydrocephalus can be caused by one or more of the following:
• Interference with normal CSF flow, due to an obstruction or blockage
in the CSF fluid pathway
• Overproduction of CSF (very rare)
• Under-absorption of CSF into the blood stream
A variety of causes can contribute to acquired hydrocephalus. Some are head injury, tumors, and meningitis.
In most cases the circumstances contributing to hydrocephalus are beyond a person’s control.