What causes hydrocephalus?
Hydrocephalus is caused due to an imbalance between the amount of cerebrospinal fluid (CSF) produced and the amount absorbed into the bloodstream. CSF is produced by the inner lining of the ventricles in the brain. CSF flows through the ventricles, from one ventricle to another, and eventually into the spaces around the brain and spinal cord. CSF is required for the proper functioning of the brain.
Excess CSF in hydrocephalus is caused due to the following:
- Obstruction: Partial or complete obstruction of the normal flow of CSF in any part of the CSF pathway.
- Poor absorption: The amount of CSF produced in the ventricles is normal, but the absorption is decreased, causing a buildup of CSF. There is usually a problem with the blood vessels in the brain, reducing their ability to absorb CSF. This usually occurs due to inflammation of the brain tissues or blood vessels due to disease or trauma.
- Overproduction: CSF is produced at a much faster rate than it can be absorbed, leading to the accumulation of CSF.
Risk factors for hydrocephalus:
The exact event causing hydrocephalus is not always known. There are several factors that trigger or increase the risk of hydrocephalus:
Risk factors for congenital hydrocephalus (present at birth or soon after birth):
- Developmentally abnormal central nervous system obstructing CSF flow
- Premature birth increases the risk of bleeding in the ventricles
- Infections during pregnancy such as rubella or syphilis, causing inflammation of the fetal brain in the uterus
Risk factors in other age groups:
- Tumors in the brain or spinal cord
- Infections of the or in the brain or spine
- Stroke causing bleeding within the brain
- Injury to the head/brain