Hydrocephalus: Definition, Causes, Symptoms, Diagnosis and Treatment

It is derived from “hydro,” which means water, and the word “cephalic,” which refers to the head.

Hydrocephalus is when excess cerebrospinal fluid builds up within the brain’s ventricles (fluid-containing cavities) and can increase pressure inside the head.

Although hydrocephalus is often described as “water in the brain,” the “water” is cerebrospinal fluid, a clear fluid that surrounds the brain and spinal cord.

Cerebrospinal fluid has three crucial functions:

  1. It acts as a “shock absorber” for the brain and spinal cord.
  2. It serves as a vehicle to deliver nutrients to the brain and remove waste.
  3. It flows between the skull and spine to regulate changes in pressure within the brain.

Hydrocephalus is a disease that can occur at any age, but its diagnosis is most often made in infants and adults over 60 years of age.

Hydrocephalus is thought to affect about one in 500 children.

Most of these cases are often diagnosed before birth, at delivery, or early childhood.


Cerebrospinal fluid is a clear fluid that surrounds the brain and spinal cord.

It works as a buffer and is responsible for supplying nutrients to the brain, removing waste, and compensating for changes in intracranial blood volume.

Hydrocephalus occurs when too much cerebrospinal fluid builds up in the brain, causing pressure that damages brain tissues.

If left untreated, it can cause permanent brain damage and affect the physical and mental development of the patient.

On the other hand, patients can lead everyday lives with very few limitations if diagnosed and treated quickly.

Hydrocephalus is usually classified into four specific types, according to the cause that causes it, such as:

  • Communicating hydrocephalus: Once the cerebrospinal fluid leaves the ventricles, the flow is blocked in this type of hydrocephalus.
  • Obstructive hydrocephalus occurs when the flow of cerebrospinal fluid is blocked along the tubes that connect the ventricles.
  • Ex vacuo hydrocephalus: This is associated with strokes and some types of traumatic brain injuries.
  • Normal-pressure hydrocephalus: It is associated with subarachnoid hemorrhages, infections, tumors, and previous brain surgery. It can sometimes develop after an injury or stroke, but the cause is unknown in most cases.

Hydrocephalus can also be classified as congenital or acquired:

  • Congenital hydrocephalus: In congenital hydrocephalus, patients are born with the condition. This is often due to problems such as spina bifida (abnormal development of the spinal cord) or aqueduct stenosis (the narrowing of a small passage, the “aqueduct of Sylvius,” connecting two central ventricles in the brain).
  • Acquired Hydrocephalus: The condition can also develop at any age after birth. It occurs after delivery and can affect people of any age. It is usually caused by bleeding in the brain.

Common causes of hydrocephalus

Although rare, hydrocephalus can be inherited genetically or associated with developmental disorders such as spina bifida (congenital disability of the spine) and encephalocele (herniation of the brain).

Other causes can include bleeding within the brain, brain tumors, head injuries, complications of premature birth such as bleeding, or diseases such as meningitis or other infections.

In some cases, the normal flow of cerebrospinal fluid in the brain is blocked, leading to fluid buildup.

Hydrocephalus can develop due to medical conditions that disrupt the brain’s normal absorption of cerebrospinal fluid.

Since the brain continuously produces and absorbs fluid, any change or interruption in this process can accumulate cerebrospinal fluid.

Some examples of problems or interruptions in this process include:

  • A blockage that prevents fluid from flowing normally.
  • Problems with the blood vessels in the brain prevent them from absorbing fluid properly.
  • Cerebrospinal fluid overproduction.

The most common causes of congenital hydrocephalus can be summarized as follows:

  • Hereditary genetic abnormalities: An example is the same defect that causes aqueduct stenosis, in which a small passage between the third and fourth ventricles of the brain narrows.
  • Developmental disorders: Between 80 and 90 percent of babies born with certain developmental conditions, such as spina bifida, meningocele, or myelomeningocele, also develop hydrocephalus.
  • Preterm birth or related complications: Intraventricular hemorrhage during preterm labor is an example of these complications.
  • Infections during pregnancy.

On the other hand, there are some risk factors associated with acquired hydrocephalus:

  • Traumatic head injury.
  • Certain diseases, including meningitis.
  • Tumors, especially those in the central nervous system.
  • As a result of brain surgery.
  • Bleeding from the blood vessel in the brain.

When everything is working, usually, the cerebrospinal fluid flows through a series of cavities (called ventricles) and narrow canals until it leaves the brain to fill the skull and spine.

The brain and spinal cord float in it. The cerebrospinal fluid is then recycled into the bloodstream.

If there is a blockage in any ventricles or something disturbs recycling, the cerebrospinal fluid recedes and causes hydrocephalus.


Hydrocephalus symptoms vary significantly from individual to individual.

The most common symptoms are listed below for reference.

In addition to having an abnormally large head, patients suffering from hydrocephalus may also experience the following symptoms:

Symptoms of Hydrocephalus in Babies

The effects of hydrocephalus in babies include abnormal head enlargement that increases rapidly, weak spot (fontanel) is tight, and bulging.

The scalp may appear thin, separate bones in the baby’s head, prominent scalp veins, vomiting, drowsiness, seizures, irritability, downward drift of the baby’s eyes, strokes, poor appetite, poor muscle tone, and lack of muscular strength.

Symptoms of Hydrocephalus in Young Children

The symptoms of hydrocephalus in young children are:

  • Abnormal head enlargement.
  • Headache.
  • Sickness.
  • Vomiting
  • Fever.
  • Blurred or double vision
  • Precarious balance.
  • Irritability.
  • Drowsiness.
  • Delayed progress when walking or talking.
  • Poor coordination.
  • Change in personality.
  • Inability to concentrate
  • Loss of sensory-motor functions.
  • Seizures
  • Lack of appetite.

Hydrocephalus Symptoms in Older Children

Older children may experience:

  • Difficulty staying awake.
  • Abnormal changes in facial structure.
  • Crossed eyes
  • Muscle spasms.
  • Growth delays.
  • Coordination problems.
  • Bladder control problems.

Symptoms of hydrocephalus in young adults and middle-aged individuals

Some of the more common hydrocephalus symptoms in adults include:

  • Headache.
  • Difficulty staying awake or waking up.
  • Loss of coordination or balance.
  • Bladder control problems.
  • Impaired vision and cognitive skills can affect job performance and personal skills.

Hydrocephalus Symptoms in Older Adults

  • Loss of coordination or balance.
  • Memory loss.
  • Headache or bladder control problems.
  • Walking difficulties
  • Gait instability.
  • Urinary incontinence
  • Bad memory.
  • Difficult to focus.
  • Dementia.

Severe and life-threatening complications of the disease include:

  • Coma.
  • Hernia uncle or amygdalina.
  • Brain compression.

About a quarter of patients with hydrocephalus also develop epilepsy.

The range and severity of symptoms depend on the age of the patient, the cause of the condition, and the extent of damage to brain tissue.

Diagnosis of hydrocephalus

The diagnosis is made through:

  • A review of the patient’s medical history, answers to questions about signs and symptoms, and a general physical exam.
  • A comprehensive neurological exam is performed, including diagnostic tests such as reflexes, muscle strength and tone, sense of touch, vision and eye movements, hearing, coordination, and mental status. The neurological exam will also help determine the severity of the condition.

Other brain imaging tests may be ordered to look for enlarged ventricles caused by excess cerebrospinal fluid, identify the underlying causes, and identify some conditions that cause the symptoms. Imaging tests are generally:

  1. Ultrasound: The ultrasound device is placed in the baby’s fontanelle. With the help of ultrasound, hydrocephalus can also be detected before birth when performing prenatal pregnancy checks.
  2. Magnetic resonance imaging: This test produces very detailed three-dimensional or cross-sectional images of the brain. This test in children requires mild sedation.
  3. Computed tomography: CT scans in hydrocephalus diagnoses are usually used for emergencies.

The tests can provide a clear picture of the inside of the brain and reveal helpful information about the severity of the condition and its possible cause.


Treatment can vary depending on the age of the patient, the cause of the accumulation of cerebrospinal fluid (whether from a blockage, overproduction of liquid, or another problem), and general health.

The problem area can be treated directly by removing the cause of the CSF obstruction or indirectly by diverting the fluid to another location, usually to another body cavity.

Indirect treatment is done by implanting a device known as a shunt to divert excess cerebrospinal fluid from the brain.

The body cavity into which cerebrospinal fluid is diverted is usually the peritoneal cavity (the area around the abdominal organs).

Once inserted, the bypass system generally remains in place for the patient’s life (although additional operations are sometimes necessary to check the bypass system).

The shunt system will continually perform its function of diverting cerebrospinal fluid from the brain, thereby keeping intracranial pressure within normal limits.

Referral procedure

In a bypass procedure, a catheter (a thin, flexible tube) is placed into the brain to drain extra fluid into the abdominal cavity, the chambers of the heart, or a space around the lungs.

Then the fluid is absorbed into the bloodstream. The shunt is implanted through a surgical procedure.

A general anesthetic is commonly administered to carry out the procedure.

The bypass tube enters the brain through a small hole drilled in the skull.

The other end of the bypass tube is inserted under the skin of the head, neck, and chest and threaded into another cavity or organ (peritoneal cavity, heart, chest, among other organs, into which fluid is drained the cerebrospinal juice and is subsequently safely absorbed by the body.

An in-line valve is included as part of the shunt system to regulate the amount of cerebrospinal fluid appropriately drained.

This valve allows the flow of cerebrospinal fluid in only one direction (out of the brain).

The surgeon will select one of the different valve systems depending on the patient’s specific needs. After surgery, the bypass system is entirely inside the body.

Antibiotics are often prescribed for a short time to reduce the risk of infection.

It is important to note that shunting is only one method of managing hydrocephalus and is not a cure. However, most patients with hydrocephalus will have improvements in symptoms after bypass.

The bypass system’s valve (a flap that opens and closes) regulates flow to prevent overtraining and underdraining.

While shunting has been an effective treatment for hydrocephalus, it burdens children and families. Some referrals last many years, but none last forever.

When they stop working, they must be repaired with another operation. As a result, some children will need many functions.

Infections are a significant complication of bypass surgery.

Most infections develop within the first few months after a bypass procedure.

Treatment usually means a hospital stay for surgery to remove the infected shunt, intravenous antibiotics, and a second operation to replace the shunt once the infection is gone.

A programmable bypass system is commonly used to treat elderly patients with normal pressure hydrocephalus.

The implantation of a programmable valve allows the neurosurgeon to adjust the pressure of the valve with a unique non-invasive device.

This, in turn, affects the flow of cerebrospinal fluid through the shunt.

Endoscopic surgery procedure

Another treatment may be considered in some cases.

For some patients with obstructive hydrocephalus, the surgeon may recommend an operation called an endoscopic ventriculostomy.

This procedure is minimally invasive for older children and adults with hydrocephalus due to a blockage and is performed with an endoscope.

An endoscope is a surgical telescope that allows the surgeon to perform simple operations inside the body through tiny openings.

In these cases, a neurosurgeon uses an endoscope to make a small hole in the third ventricle floor.

The surgeon uses a miniaturized camera to look inside the ventricles in this operation.

By making a small opening through a membrane near the bottom of the brain, the surgeon creates a new pathway through which cerebrospinal fluid can flow.

This pathway drains fluid from the brain and bypasses any blockage causing it.

The body then absorbs the cerebrospinal fluid into the bloodstream as it normally would.

Endoscopic ventriculostomy alone was not a very successful treatment for children with hydrocephalus until surgeons began adding a second step, choroid plexus coagulation.

The choroid plexus is the tissue within the ventricles that produces cerebrospinal fluid, and destroying this tissue with an electrical current makes endoscopic treatment much more effective.

Endoscopic ventriculostomy with choroid plexus coagulation can prevent a shunt for many babies with spina bifida and some babies with hydrocephalus from other causes, such as prematurity.

These patients generally do not need a shunt after surgery.

But children who have endoscopic treatment often need to follow up with their care team.

If they develop hydrocephalus again, doctors usually have to do a bypass procedure because repeat endoscopic surgery is unlikely to work.

The risks of this operation include a slightly increased chance of bleeding from an arterial injury and the possibility that the opening, which the surgeon creates, will gradually close over time.

Many neurosurgeons do not perform an endoscopic ventriculostomy in children younger than two years because the failure rate is higher than for older children. It is essential to treat hydrocephalus right away.

Untreated hydrocephalus can get worse and cause more nervous system problems.


Most patients with hydrocephalus require:

  • Occupational therapy: to develop daily skills.
  • Developmental treatment: which helps children develop appropriate behaviors based on their age, social skills, and interpersonal skills
  • Psychologist, psychiatrist.
  • Special Education Specialist: to treat learning difficulties.