What Is Hydrocephalus?

Hydrocephalus is a medical condition characterized by excess fluid on the brain. Learn more about the causes, symptoms, and available treatment options.

premature baby girl OndroM/Shutterstock

Everyone needs a certain amount of cerebrospinal fluid (CSF) for healthy brain function. It normally circulates through the brain's cavities, cushioning the brain and spinal cord, and absorbs into the bloodstream. Those with hydrocephalus, however, have too much CSF, causing excessive pressure on the brain. This can lead to physical and mental impairment, brain tissue damage, and other serious side effects.

While serious, hydrocephalus isn't a death sentence. In fact, depending on the individual's specific cause of hydrocephalus, there are times when just one procedure can diminish the condition to a manageable state. Most patients who receive treatment go on to lead otherwise healthy lives.

Although it's just as common as Down syndrome, most people don't know much about hydrocephalus. Read on to learn more about the causes, symptoms, and treatment options.​

Hydrocephalus Causes

There's a higher risk of developing hydrocephalus in underdeveloped countries because of poor birthing conditions and prenatal care. Even so, it affects babies and fetuses all over the world. According to research from the Hydrocephalus Association, which raises awareness and promotes a cure, one or two out of every 1,000 babies are born with hydrocephalus, and more than one million total Americans are affected today.

Hydrocephalus falls into two categories: congenital and acquired, according to David Harter, M.D., a neurosurgeon in New York City, Congenital hydrocephalus is present at birth, usually resulting from atypical brain development in the womb. It's also caused by genetic abnormalities like aqueductal stenosis (an obstruction in the brain), Dandy-Walker syndrome (brain malformation), and arachnoid cysts.

Hydrocephalus in Infants

Babies born prematurely have a higher risk of developing congenital hydrocephalus. "Kids born prematurely can develop a hemorrhage, which causes obstruction and inflammation in the brain," says Ramin Eskandari, M.D., a pediatric neurosurgeon in Charleston, South Carolina. "The risk of an intraventricular hemorrhage decreases as gestational range increases." What's more, many children born with spina bifida (specifically myelomeningocele, the most severe form) end up with hydrocephalus.

hydrocephalus baby Provided by Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities. (Public domain). 

Hydrocephalus doesn't always develop in the womb or during infancy; anyone at any age can develop it. Acquired hydrocephalus develops after childbirth and causes include brain tumors, head trauma, bleeding in the brain, and central nervous system infections like meningitis, according to Dr. Harter.

Hydrocephalus Symptoms and Signs

Doctors sometimes spot hydrocephalus in a fetus through ultrasound. But hydrocephalus in infants can go undetected for months, says Amanda Garzon, the director of communications and marketing for the Hydrocephalus Association, who has a 17-year-old daughter with the condition. "Kids have incredibly elastic skulls, and their heads grow to accommodate excess fluid on the brain. With a gradual increase in fluid, you won't see anything to alert you to hydrocephalus," she says.

When the cranial vault begins to fuse together later in infancy, however, an enlarged head becomes more obvious. "The head may be twice the size of the body in severe cases," notes Dr. Eskandari.

Other symptoms of hydrocephalus in infants are:

  • A tense fontanel (soft spot on a baby's head)

  • Vomiting

  • "Sun setting" (downward-pointing eyes)

  • Prominent scalp veins

  • Lethargy

  • Irritability

  • Seizures

For older children, hydrocephalus symptoms also include:

  • Headache

  • Nausea

  • Poor balance

  • Blurred vision

  • Decreased mental capacity

  • Personality changes

  • Bladder issues

Adopting a Child with Spina Bifida

Hydrocephalus Treatment

Dr. Harter says hydrocephalus is diagnosed through clinical examination, ultrasound, CT, or MRI. After diagnosis, treatment is vital to prevent mental disabilities, brain tissue damage, and other complications. "Hydrocephalus is on a spectrum, like any other disease," says Dr. Eskandari. "A baby with severe hydrocephalus will eventually die without treatment because fluid pushes on the brain stem, causing respiratory problems, heart problems, and the body to shut down."

If the hydrocephalus cause is a tumor or cyst, removing the growth can alleviate the condition. More commonly, a neurosurgeon will install a shunt (flexible plastic tube) through surgery. The shunt redirects cerebrospinal fluid to the abdominal cavity, preventing excess fluid on the brain. Garzon says shunts can also drain CSF to the heart, where it gets recirculated through the bloodstream.

While shunts save many lives, the Hydrocephalus Association notes that 50% fail within two years of implementation. "The shunt has a high failure rate because tissue and other debris clog it," says Garzon, adding that her daughter with hydrocephalus has undergone 16 brain surgeries for her shunts. Drainage problems and infections like Staphylococcus Epidermidis may also require shunt replacement.

Another hydrocephalus treatment, endoscopic third ventriculostomy (ETV), involves looking inside the brain with a tiny camera, then creating a hole to redirect cerebrospinal fluid. Candidacy for ETV depends on the hydrocephalus cause; for example, those with brain bleeds usually can't get one. The Hydrocephalus Association claims success rates are up to 90%, depending on individual circumstances. No matter the treatment option, though, Dr. Eskandari says most people with hydrocephalus lead otherwise normal lives.