"Hydro-" means water, and "-cephalus" refers to the head. Hydrocephalus is too much water inside the head. It's sometimes called "water on the brain."
Your brain has several hollow spaces inside it that are filled with fluid. In hydrocephalus, there is too much fluid in these spaces.
A baby's skull is made of several different bones. For the first couple of years, these bones are only loosely connected. Later, the bones grow together into one solid bone. But before the bones grow together, increased fluid pressure inside the brain can make the bones spread apart. This keeps the pressure from getting dangerously high, but it makes the baby's head bigger. The skull of older children and adults can't expand, so increased pressure damages the brain and can be rapidly fatal.
The following can cause extra fluid in the brain:
Babies can be born with hydrocephalus, or it can happen after birth.
The symptoms of hydrocephalus depend on where and how much fluid there is. A baby with hydrocephalus may:
Older children may have a headache, vision problems, or both.
If not treated, children with hydrocephalus can have learning disabilities or lose vision.
Doctors do routine tests before and after a baby is born to test for hydrocephalus:
Doctors treat hydrocephalus in different ways depending on what's causing it, how much fluid there is, and if it’s getting worse.
If there's not much extra fluid and it's not getting worse, your baby may not need treatment.
To temporarily help relieve symptoms, doctors may:
Take fluid out with a needle put into the brain or sometimes the lower back (spinal tap)
If there's a lot of fluid or the fluid is causing symptoms, doctors may:
With a shunt, one end of the plastic tube is in the fluid-filled space in the brain. The tube goes under the baby's skin and the other end is inside the belly. This creates a path for fluid to drain from the brain.
Shunts are usually permanent, but sometimes doctors can remove them as the child grows older.
A shunt can get clogged up, break, or get infected. If so, the shunt may have to be replaced.