What Is Hydrocephalus?

What Is Hydrocephalus?

Hydrocephalus is a condition caused by an increase of cerebrospinal fluid (CSF) in and around the brain. It can occur at the time of birth or during infancy, childhood, or adolescence.

Normally, circulating CSF is constantly replenished and absorbed so that the amount of fluid inside the brain and skull remains constant over a lifetime. Hydrocephalus occurs when the brain's normal flow of cerebrospinal fluid (CSF) is altered. This disruption can occur when there is excess cerebrospinal fluid produced, it is not properly absorbed, and/or a blockage obstructs it.

Hydrocephalus can occur during pregnancy. When it does, it is called congenital hydrocephalus. Other instances of hydrocephalus arise after birth. Possible causes include bleeding, infection, trauma, tumors, vascular problems, spina bifida, and structural problems.

Types of Hydrocephalus


There are two main types of hydrocephalus, and they occur in different compartments of the brain. This distinction provides a solid foundation for determining management options:

  • Noncommunicating hydrocephalus, also called obstructive hydrocephalus, occurs when there is a blockage of CSF flow anywhere within the ventricles (large open structures). This limits flow to the subarachnoid space, the surfaces of the brain and spinal cord where CSF resorption normally takes place.
  • Communicating hydrocephalus results from impaired reabsorption of CSF into the subarachnoid space of the brain, therefore limiting CSF access into the venous circulatory system. Internal circulation of CSF within the ventricles is normal.

Hydrocephalus can be further classified based on when the condition presents itself:

  • Congenital hydrocephalus is present at birth.
  • Acquired hydrocephalus develops at some point after birth.
  • Normal pressure hydrocephalus can develop at any age but is most common among the elderly.

Signs & Symptoms of Hydrocephalus


Symptoms of hydrocephalus are age dependent. During early infancy, hydrocephalus is usually detected by the family or pediatrician as macrocephaly (an abnormally large head). Macrocephaly rarely occurs later in infancy and childhood.

Common hydrocephalus symptoms for newborns and infants include:

  • Vomiting
  • Eye gaze pointed downward
  • Nystagmus (involuntary eye movements)
  • Progressive weakness and spasticity
  • Poor feeding
  • Failure to thrive
  • Delay or loss of developmental milestones
  • Unusual sleepiness
  • Irritability
  • Poor head control
  • A bulging “soft spot” at the top of the head

Symptoms during older childhood and adolescence may include:

  • Headache
  • Vomiting and nausea
  • Urinary incontinence
  • Visual disturbances, such as blurred vision or diplopia
  • Nystagmus (involuntary eye movements)
  • Irritability
  • Eye gaze pointed downward

If your child has any of these symptoms, he or she should be evaluated to determine if diagnostic imaging is needed, because hydrocephalus can cause neurological damage as the excess fluid puts pressure on surrounding brain tissue.

Because many of these symptoms can be caused by a range of other neurological disorders and conditions, an accurate diagnosis is critical. Our pediatric specialists can perform a range of tests to correctly confirm a diagnosis and provide treatment for hydrocephalus.

What Causes Hydrocephalus?


Hydrocephalus occurs when there is an abnormal accumulation of cerebrospinal fluid in the brain and spinal column. Cerebrospinal fluid flows around the brain and spinal cord, supporting these body structures and transporting waste away from the brain. It usually flows through the brain ventricles and is absorbed by blood vessels on the surface of the brain. If this fluid builds up, it puts pressure on the brain, potentially damaging it.

Hydrocephalus can result from obstruction of the ventricles, poor absorption of cerebrospinal fluid, or an overproduction of cerebrospinal fluid. These issues can occur due to a genetic disorder, illness, injury, or infection. In many cases, the cause of hydrocephalus is unknown.

Risk Factors

Risk Factors

Some factors may increase a person’s risk for developing hydrocephalus, including:

  • Abnormal development of the central nervous system, including birth defects like spinal bifida and Dandy Walker syndrome
  • An infection of the uterus during pregnancy, like syphilis, can cause the fetal brain tissue to become inflamed
  • Premature birth complications, like bleeding within the fetus’ brain ventricles
  • Tumors of the brain or spinal cord
  • Bleeding in the brain caused by head injury or stroke



Depending on the severity, hydrocephalus can cause significant complications and can even be fatal. If left untreated, the condition causes brain damage, which can result in physical, developmental, and intellectual disabilities.

Children born with severe hydrocephalus will likely have already sustained brain damage, while those who develop the condition later and receive prompt treatment may experience relatively few complications.

Get Care

Trust NewYork-Presbyterian for Hydrocephalus Care

Prompt and effective treatment is imperative for achieving the best prognosis for hydrocephalus. The pediatric team at NewYork-Presbyterian is highly trained to recognize the signs of hydrocephalus and determine a course of action to treat hydrocephalus, collaborating with a multidisciplinary team to choose the best care plan for your child.