Overview

Hydrocephalus is the buildup of fluid in the cavities (ventricles) deep within the brain. The excess fluid increases the size of the ventricles and puts pressure on the brain.

Cerebrospinal fluid normally flows through the ventricles and bathes the brain and spinal column. But the pressure of too much cerebrospinal fluid associated with hydrocephalus can damage brain tissues and cause a range of brain function problems.

Hydrocephalus can happen at any age, but it occurs more frequently among infants and adults 60 and over. Surgical treatment for hydrocephalus can restore and maintain normal cerebrospinal fluid levels in the brain. Different therapies are often required to manage symptoms or problems resulting from hydrocephalus.

Symptoms

The signs and symptoms of hydrocephalus vary somewhat by age of onset.

Infants

Common signs and symptoms of hydrocephalus in infants include:

Changes in the head

  • An unusually large head
  • A rapid increase in the size of the head
  • A bulging or tense soft spot (fontanel) on the top of the head

Physical signs and symptoms

  • Nausea and vomiting
  • Sleepiness or sluggishness (lethargy)
  • Irritability
  • Poor eating
  • Seizures
  • Eyes fixed downward (sunsetting of the eyes)
  • Problems with muscle tone and strength

Toddlers and older children

Among toddlers and older children, signs and symptoms might include:

Physical signs and symptoms

  • Headache
  • Blurred or double vision
  • Abnormal eye movements
  • Abnormal enlargement of a toddler's head
  • Sleepiness or sluggishness
  • Nausea or vomiting
  • Unstable balance
  • Poor coordination
  • Poor appetite
  • Loss of bladder control or frequent urination

Behavioral and cognitive changes

  • Irritability
  • Change in personality
  • Decline in school performance
  • Delays or problems with previously acquired skills, such as walking or talking

Young and middle-aged adults

Common signs and symptoms in this age group include:

  • Headache
  • Sluggishness
  • Loss of coordination or balance
  • Loss of bladder control or a frequent urge to urinate
  • Vision problems
  • Decline in memory, concentration and other thinking skills that may affect job performance

Older adults

Among adults 60 years of age and older, the more common signs and symptoms of hydrocephalus are:

  • Loss of bladder control or a frequent urge to urinate
  • Memory loss
  • Progressive loss of other thinking or reasoning skills
  • Difficulty walking, often described as a shuffling gait or the feeling of the feet being stuck
  • Poor coordination or balance

When to see a doctor

Seek emergency medical care for infants and toddlers with these signs and symptoms:

  • A high-pitched cry
  • Problems with sucking or feeding
  • Unexplained, recurrent vomiting
  • Seizures

Seek prompt medical attention for other signs or symptoms in any age group.

More than one condition can cause the problems associated with hydrocephalus, so it's important to get a timely diagnosis and appropriate care.

Causes

Hydrocephalus is caused by an imbalance between how much cerebrospinal fluid is produced and how much is absorbed into the bloodstream.

Cerebrospinal fluid is produced by tissues lining the ventricles of the brain. It flows through the ventricles by way of interconnecting channels. The fluid eventually flows into spaces around the brain and spinal column. It's absorbed primarily by blood vessels in tissues on the surface of the brain.

Cerebrospinal fluid plays an important role in brain function by:

  • Keeping the brain buoyant, allowing the relatively heavy brain to float within the skull
  • Cushioning the brain to prevent injury
  • Removing waste products of the brain's metabolism
  • Flowing back and forth between the brain cavity and spinal column to maintain a constant pressure within the brain — compensating for changes in blood pressure in the brain

Too much cerebrospinal fluid in the ventricles occurs for one of the following reasons:

  • Obstruction. The most common problem is a partial blockage of the flow of cerebrospinal fluid, either from one ventricle to another or from the ventricles to other spaces around the brain.
  • Poor absorption. Less common is a problem with absorbing cerebrospinal fluid. This is often related to inflammation of brain tissues from disease or injury.
  • Overproduction. Rarely, cerebrospinal fluid is created more quickly than it can be absorbed.

Risk factors

In many cases, the cause of hydrocephalus is unknown. However, a number of developmental or medical problems can contribute to or trigger hydrocephalus.

Newborns

Hydrocephalus present at birth (congenital) or shortly after birth can occur because of any of the following:

  • Abnormal development of the central nervous system that can obstruct the flow of cerebrospinal fluid
  • Bleeding within the ventricles, a possible complication of premature birth
  • Infection in the uterus — such as rubella or syphilis — during pregnancy, which can cause inflammation in fetal brain tissues

Other contributing factors

Other factors that can contribute to hydrocephalus among any age group include:

  • Lesions or tumors of the brain or spinal cord
  • Central nervous system infections, such as bacterial meningitis or mumps
  • Bleeding in the brain from a stroke or head injury
  • Other traumatic injury to the brain

Complications

In most cases, hydrocephalus progresses, which means complications, including intellectual, developmental and physical disabilities, can occur if it's not treated. It can also be life-threatening. Less severe cases, when treated appropriately, might have few, if any, serious complications.