Congenital Hydrocephalus

What is congenital hydrocephalus?

Congenital hydrocephalus is a buildup of excess cerebrospinal fluid (CSF) within the brain that is present at birth. The excess fluid can increase pressure in the baby's brain, possibly resulting in brain damage and loss of mental and physical abilities. Prompt diagnosis and treatment is important to help limit serious long-term problems. But long-term effects of congenital hydrocephalus mostly depend on what causes it, how bad it gets, and how a baby responds to treatment.

See a picture of congenital hydrocephalus.

Research shows that about 1 baby out of every 1,000 is born with the condition.¹ This means about 999 babies out of every 1,000 are not born with hydrocephalus. The condition also occurs in most children who are born with open neural tube defects.¹

Another form of hydrocephalus, called acquired hydrocephalus, may occur at any time after birth. This topic covers only congenital hydrocephalus.

What causes congenital hydrocephalus?

Congenital hydrocephalus is caused by an imbalance between the brain's production of cerebrospinal fluid (CSF) and the body's ability to distribute or absorb it properly.

Normally, CSF flows through and out of chambers in the brain called ventricles, and then around the brain and spinal cord, providing nutrition and a protective cushion. The fluid is then reabsorbed by the thin tissue that surrounds the brain and spinal cord. With hydrocephalus, the fluid can't move where it needs to or is not absorbed as it should be. And in rare cases, the brain makes too much CSF.

Congenital hydrocephalus may result from either genetic or other causes, such as prenatal hemorrhage (bleeding in the fetus before birth) or infections, such as toxoplasmosis, syphilis, cytomegalovirus (CMV), rubella, or mumps. The condition is often associated with other birth defects, especially spina bifida.

What are the symptoms?

The most obvious symptom of hydrocephalus is an unusually large head that is noticed at birth or within the first 9 months of life. But keep in mind that babies' heads grow a lot during the first year. It is only when the head size grows faster than the normal rate for a baby's height and weight that doctors may become concerned. Also, the soft spot (fontanelle) may feel firm or bulge outward. Other symptoms in an infant may include irritability, excessive sleeping, vomiting, poor feeding, and eyes that gaze downward much of the time.

How is congenital hydrocephalus diagnosed?

Most cases of congenital hydrocephalus are diagnosed during a physical exam soon after birth based on the larger-than-normal size of the baby's head. In rare cases, a diagnosis is made later in childhood. There may be reasons other than congenital hydrocephalus for why a baby has a larger-than-normal head. Imaging tests are usually done to see whether congenital hydrocephalus is a possibility. A computed tomography (CT) scan, magnetic resonance imaging (MRI), or ultrasound may be done to help confirm the diagnosis or to provide a more detailed picture of the brain and its structures.

Images from a fetal ultrasound can sometimes indicate congenital hydrocephalus before birth.

How is it treated?

Early treatment—within a baby's first 3 to 4 months—is important to help limit or prevent brain damage. The long-term effects of congenital hydrocephalus depend largely on the cause of the condition, its severity, and the response to treatment.

Treatment generally consists of surgically inserting a flexible tube (shunt) in the brain to drain the cerebrospinal fluid. The shunt will remain in the brain permanently but may need to be repaired or replaced if a problem develops.

Endoscopic third ventriculostomy (ETV) is sometimes performed instead of surgical shunt placement. ETV is a surgical procedure in which a small hole is made in a ventricle in the brain, allowing CSF to flow freely. It is often done when hydrocephalus seems to be a result of a blockage between ventricles. If used as treatment for congenital hydrocephalus, it is more likely to be tried after a shunt malfunction or infection. ETV was once thought to be a permanent solution for redirecting CSF flow, but it has been shown to fail over time. Babies younger than 6 months of age usually are not good candidates for this procedure.

Children with congenital hydrocephalus are at increased risk for developmental disabilities and may require treatment such as speech therapy or physical therapy.

Frequently Asked Questions

The symptoms of congenital hydrocephalus usually are noticed at birth or within the first 9 months of life. Symptoms may not be as obvious in toddlers and older children. A baby may have:

• A large head that may get bigger very quickly. Usually a baby with congenital hydrocephalus will have a noticeably bigger head than other babies the same age.
• A slightly bulging soft spot (fontanelle) on top of the head that doesn't go away when the baby is held upright. A baby may also have larger-than-normal areas between the skull bones (sutures).
• A shiny scalp, with prominent blood vessels.
• A downward gaze and retracted eyelids, which reveal the whites of the eyes above the irises ("sun-setting of the eyes").

If pressure in the baby's head builds, symptoms will get worse and may include:

• Irritability.
• Excessive sleeping.
• Poor appetite and frequent vomiting.
• Inability to track you well with his or her eyes.
• High-pitched crying.

Other types of hydrocephalus may produce the same or similar symptoms at any age.

Congenital hydrocephalus is sometimes diagnosed before birth with a fetal ultrasound. However, most cases are diagnosed during a physical exam at or soon after birth. Congenital hydrocephalus usually is first suspected because of a larger-than-normal head size. A doctor will also look for other physical signs, such as eyes that almost always look down and a lot of white showing above the irises ("sunsetting of the eyes"). A doctor will also ask about how your baby is eating and sleeping or whether he or she has seemed fussy.

A health professional may request one or more tests to confirm a diagnosis of congenital hydrocephalus or to further evaluate the condition. Imaging tests may be used to determine whether extra fluid is building in the brain, to look at the brain's structure, or to evaluate the flow of cerebrospinal fluid within and through the brain's ventricles and into the spinal column. These tests include:

• A cranial ultrasound, if the soft spots (fontanelles) are still open. Open fontanelles make it easier to see the brain during an ultrasound.
• A computed tomography (CT) scan of the head or a CT scan of the spine.
• A magnetic resonance imaging (MRI) of the head or MRI of the spine.

Other tests that may be done include:²

• Lumbar puncture, a procedure in which doctors take a sample of cerebrospinal fluid (CSF). Doctors analyze the CSF sample to see whether an infection may be causing symptoms. This test helps doctors to measure the pressure of CSF within the skull. It may also allow some controlled drainage of CSF. A lumbar puncture usually is only done for communicating hydrocephalus, which is hydrocephalus not caused by an obstruction.
• Genetic test, which examines a DNA sample to test for abnormal genes or to analyze the number, arrangement, and characteristics of the chromosomes. This may be done if the parents' medical histories indicate the possibility that a baby has inherited hydrocephalus. Genetic counseling is recommended along with this testing.

Treatment for congenital hydrocephalus focuses on lowering the amount of cerebrospinal fluid (CSF) in the brain to relieve pressure. Early treatment—within a baby's first 3 to 4 months—is important to help limit or prevent brain damage. But the long-term effects of congenital hydrocephalus depend largely on the cause of the condition, its severity, and the response to treatment. Other problems within the brain can also affect a child's outcome.

Initial treatment

When a newborn is diagnosed with congenital hydrocephalus, a shunt usually is surgically inserted in the brain to drain excess cerebrospinal fluid (CSF). Generally, one end of the shunt is placed in the ventricles in the brain and then is threaded out of the brain just below the skin under the scalp. Continuing under the skin, it goes behind the ear, down the neck, and into another part of the body—usually the abdomen—which then absorbs the CSF. Removing the excess fluid lowers the pressure within the brain, which helps to prevent or minimize brain damage.

Sometimes temporary emergency measures are needed to reduce or drain fluid until a shunt can be inserted. Such treatments may include:

• Acetazolamide or furosemide medicines, to slow the production of CSF in the brain. But the safety and effectiveness of these medicines are questionable.³
• Occasionally a lumbar puncture, which can help drain CSF from the brain until a shunt can be surgically implanted.
• Draining the CSF from the skull so it collects in a bag outside of the body. This is often done when a child cannot get a permanent shunt placed right away.

For noncommunicating hydrocephalus (caused by an obstruction), a surgical procedure called endoscopic third ventriculostomy (ETV) may be done instead of a shunt placement. In ETV, a small hole is made in the third ventricle of the brain, allowing cerebrospinal fluid to flow freely. While ETV may be used during ongoing treatment as a way to prevent shunt placement, it is not used as initial treatment in newborns. If ETV fails during ongoing treatment, your child will need a shunt placed at a later time.¹ Regardless of whether ETV or a shunt is used, your child will need to be watched closely over time to make sure the cerebrospinal fluid drains properly.

Ongoing treatment

Ongoing treatment for congenital hydrocephalus usually requires lifelong shunt use and close monitoring by health professionals, which may include a neurologist, a neurological surgeon, a family medicine doctor, a pediatrician, and a developmental pediatrician.

During routine appointments, your doctor will usually measure the size of your child's head and check your child's eyes for signs of pressure. Your doctor will also assess your child's neurological development and find out whether he or she has the same abilities as most other children around the same age. For example, if your child is about 12 months old, your doctor may ask you whether he or she can say a few words. At some visits, your doctor may order a computed tomography (CT) scan or magnetic resonance imaging (MRI) of the head and spine to ensure that cerebrospinal fluid (CSF) is draining properly.

Be alert for signs of shunt infection or malfunction. Excess CSF buildup in the brain can result in permanent brain damage.

• About 40% of shunts fail within the first 2 years.⁴ Shunt failure or malfunction allows fluid to build up within the brain, producing symptoms of irritability, excessive sleeping, poor appetite, frequent vomiting, eye-tracking problems, and high-pitched crying. After early childhood, additional symptoms may be noticed, such as vision problems, neck pain, confusion or behavioral changes, problems walking, seizures, or urinary incontinence.
• If the shunt causes infection, these same symptoms may occur, along with a fever. The chances of the shunt becoming infected are about 3% to 15%.⁴ Infections can develop at any time, but they most often occur within the first 3 months after shunt placement.
• The cause of the shunt malfunction or type of infection must be determined in order to properly manage the problem. For example, a shunt tap, a lumbar puncture, and fluid analysis may be done to confirm a suspected infection and to identify the type of bacteria present. This information allows a health professional to prescribe the most effective antibiotic.

For noncommunicating (obstructive) congenital hydrocephalus, an endoscopic third ventriculostomy (ETV) may be done instead of inserting a shunt. Although babies usually are not able to have this procedure, it may be used later instead of shunt replacement or repair. For an ETV, an endoscope is inserted through a small hole and helps open ventricles within the brain so CSF fluid is diverted around the blockage and absorbed outside of the brain without an implanted shunt. Once thought to be a permanent solution for some cases of obstructive congenital hydrocephalus, ETVs can also fail over time. It is important to have close monitoring for any signs of CSF buildup within the brain.

Regardless of the type of treatment, pay close attention for signs of any brain damage that affects function, such as delayed learning, failure to reach developmental milestones, or losing any physical or mental skills. Problems or delays are treated according to the specific issue (for instance, speech therapy for speech delays).

Your health professionals will discuss whether your child will need special care or have lifestyle restrictions. If problems from brain damage develop, you will be guided to the appropriate therapy or developmental program.

Treatment if the condition gets worse

No permanent cure for congenital hydrocephalus exists. Even when initial treatment is successful, cerebrospinal fluid (CSF) can build up within the brain again, causing symptoms to recur. Usually, problems are related to shunt malfunction or infection, requiring repair or replacement.

• Shunts have a 2-year failure rate of 40%.⁴ Shunt failure or malfunction causes fluid to once again build up within the brain, producing symptoms of irritability, excessive sleeping, poor appetite, frequent vomiting, eye-tracking problems, and high-pitched crying. After early childhood, additional symptoms may be noticed, such as vision problems, neck pain, confusion or behavioral changes, problems walking, seizures, or urinary incontinence.
• If the shunt causes infection, these same symptoms may occur, along with a fever. The chances of the shunt becoming infected are 3% to 15%.⁴ Infections most often occur within the first 3 months after shunt placement.
• The cause of the shunt malfunction or type of infection must be determined in order to properly manage the problem. For example, a shunt tap, lumbar puncture, and fluid analysis may be done to confirm a suspected infection and to identify the type of bacteria present. This information allows a health professional to prescribe the most effective antibiotic. If an infection is present, doctors will likely remove and replace the shunt.

CSF can also build up again after failure of an endoscopic third ventriculostomy (ETV). If this happens, surgery is needed to either repeat the ETV or to implant a shunt.

If CSF buildup is an emergency, it can be drained by penetration through the scalp or skull until the child is stabilized enough to have further surgical treatment.

Permanent brain damage caused by excess CSF buildup requires treatment that focuses on specific developmental problems. For example, if brain damage causes cognitive disability (mental retardation), treatment will target a wide range of issues, such as speech and motor skill development.

Your health professionals will discuss with you whether your child will need special care or have lifestyle restrictions. You will also be taught to recognize developmental delays or other signs of brain damage. If problems from brain damage develop, you will be guided to the appropriate therapy or developmental program.

Home treatment for congenital hydrocephalus consists of monitoring your child for any changes that might indicate pressure on the brain or failure of a shunt.

• Watch for signs of fluid buildup in the brain. You will need to periodically evaluate head circumference and be alert for symptoms, such as irritability, excessive sleeping, poor appetite, frequent vomiting, eye-tracking problems, and high-pitched crying. If your child has a shunt, these symptoms may indicate that it is not functioning properly.
• Be alert for signs of cerebrospinal fluid (CSF) buildup after early childhood. Additional symptoms that may be noticed include headaches that get worse over time, vision problems, neck pain, confusion, slurred speech, behavioral changes, problems walking, seizures, or urinary incontinence.
• In addition to the above symptoms, shunt infections may also produce a fever and redness along the shunt tract or valve.

See your health professional immediately if you notice any of these problems.

For the caregiver

Being a parent of a child with congenital hydrocephalus can be full of challenges. Although many children who are diagnosed and treated early avoid severe long-term problems, it can be difficult to handle the uncertainty of whether symptoms will return. Also, congenital hydrocephalus sometimes causes brain damage that impacts your child's physical or mental abilities. Take good care of yourself so you have the energy to take proper care of and enjoy your child.

While there are no official guidelines to restrict activities in children who have shunts, some doctors may suggest that severe contact sports be restricted.

You may want to ask your health professionals about support groups and organizations that can assist you with managing your child's special needs. For more information on available resources, see the Other Places to Get Help section of this topic.

Organizations

• Growth and Development, Ages 1 to 12 Months
• Growth and Development, Newborn
• Spina Bifida

Citations

1. Feldstein NA, Anderson R (2006). Diagnosis and management of hydrocephalus. In FD Burg et al., eds., Current Pediatric Therapy, 18th ed., pp. 374–377. Philadelphia: Saunders Elsevier.

2. Seiff ME (2003). Hydrocephalus section of Developmental, neurocutaneous, and genetic metabolic disorders. In RW Evans, ed., Saunders Manual of Neurologic Practice, pp. 889–895. Phildelphia: Saunders.

3. Whitelaw A, et al. (2007). Diuretic therapy for newborn infants with posthemorrhagic ventricular dilatation. Cochrane Database of Systematic Reviews (2).

4. Kulkarni AV, et al. (2001). Cerebrospinal fluid shunt infection: A prospective study of risk factors. Journal of Neurosurgery, 94(2): 195–201.

Other Works Consulted

• Fishman MA (2003). Hydrocephalus section of Disturbances in neural tube closure and spine. In CD Rudolph et al., eds., Rudolph's Pediatrics, 21st ed., pp. 2180–2184. New York: McGraw-Hill.

• Kinsman SL, Johnston MV (2007). Hydrocephalus section of Congenital anomalies of the central nervous system. In RM Kliegman et al., eds., Nelson Textbook of Pediatrics, 18th ed., pp. 2452–2455. Philadelphia: Saunders Elsevier.

• Prockop LD (2005). Hydrocephalus. In LP Rowland, ed., Merritt's Neurology, 11th ed., chap. 49, pp. 349–356. Philadelphia: Lippincott Williams and Wilkins.