Definition

Hydrocephalus is a condition characterized by the accumulation of fluid in the brain. The term comes from the Greek words "hydro," meaning water, and "cephalus," meaning head. Congenital hydrocephalus, present at birth, develops during fetal development.

Congenital hydrocephalus is caused by brain formation disorders or birth defects that lead to fluid buildup in the brain. The accumulating fluid is not ordinary water but cerebrospinal fluid (CSF). CSF is a clear, colorless fluid that surrounds the brain and spinal cord, protecting them from injury. It also carries nutrients and removes waste from the brain and spinal cord.

In healthy individuals, CSF produced by the brain is absorbed by the body. In patients with hydrocephalus, there is an imbalance between the rate of CSF production and its absorption. The fluid fails to circulate and accumulates, causing the head to enlarge and increasing pressure in the brain.

Congenital hydrocephalus occurs in about one in every 1,000 newborns. Another type, acquired hydrocephalus, occurs after birth. This type is rarer and can result from tumors, injuries, or other conditions that obstruct CSF absorption. The treatment for acquired hydrocephalus depends on the underlying cause.

Causes

Congenital hydrocephalus can be genetic or caused by other factors during pregnancy. Generally, the imbalance between CSF production and absorption occurs due to the following:

• The ventricles or spaces in the brain where CSF is produced generate too much fluid, as in choroid plexus papilloma.
• There is an obstruction that prevents the normal flow of fluid, causing it to accumulate.
• The brain’s blood flow cannot absorb all the fluid.

Problems associated with congenital hydrocephalus include:

• Aqueductal stenosis: A type of blockage where the pathway between the third and fourth ventricles in the brain narrows or is blocked, preventing fluid circulation. This can be caused by infections, tumors, or bleeding and is the most common cause.
• Neural tube defects: Such as spina bifida, where the spinal cord is open at birth, often lacking CSF. In some cases, the CSF flow from the brain can be blocked.
• Infections during pregnancy: Such as rubella, can cause inflammation of the fetal brain tissues.
• Arachnoid cysts: Growths in the brain that can obstruct fluid flow.
• Dandy-Walker syndrome: A condition where parts of the brain do not develop properly, with an enlarged fourth ventricle due to a narrow or closed exit pathway.
• Chiari malformation: Where the brain and spinal cord join abnormally, causing the lower part of the brain to be pushed into the spinal canal, leading to blockages.
• Hydranencephaly: A rare condition where the cerebral hemispheres are absent and replaced by CSF-filled sacs.
• Schizencephaly: A very rare disorder marked by abnormal clefts in the brain.
• Galen vein malformation: An abnormal connection between arteries and veins in the brain that develops before birth.

Risk factor

Risk factors for congenital hydrocephalus include:

• Abnormal development of the central nervous system that can obstruct CSF flow.
• Intraventricular hemorrhage, possibly a complication of premature birth.
• Infections in the womb, such as rubella or syphilis during pregnancy, can cause inflammation of fetal brain tissue.

Symptoms

Symptoms of congenital hydrocephalus in newborns include:

• Eyes gazing downward, known as "sun-setting."
• Irritability
• Seizures
• Drowsiness
• An unusually large head or rapid head growth compared to the rest of the body
• Vomiting

Diagnosis

Diagnosis can be made either when the baby is still in the womb or after birth.

• Pre-natal diagnosis: Regular pregnancy check-ups and ultrasounds can detect brain development problems like ventricular enlargement. With advanced imaging technology, congenital hydrocephalus can be detected as early as the third or fourth month of pregnancy. By the fifth or sixth month, abnormal enlargement of brain cavities will be more apparent. Tests to assess the baby’s condition before birth include:
• Amniocentesis: Sampling amniotic fluid from the uterus to check the baby’s chromosomes and detect other birth defects associated with hydrocephalus.
• Ultrasound: Performed by a radiologist or obstetrician to determine abnormal fluid accumulation. However, this test cannot show blockages. If a problem is found on ultrasound, further tests can provide a more detailed diagnosis.
• Post-natal diagnosis: While congenital hydrocephalus can be detected before birth, it is more often diagnosed at birth or shortly thereafter. To diagnose, doctors thoroughly evaluate the baby's physical condition and inquire about family health history, especially if there are relatives with neural tube defects. Supporting examinations using imaging techniques such as ultrasound, CT scan, MRI, or brain pressure monitoring techniques may also be performed.

Management

Although hydrocephalus can be diagnosed during pregnancy, treatment usually begins after the baby is born.

The most common treatment for congenital hydrocephalus is the creation of a shunt system. A surgeon places a flexible plastic tube in the baby’s brain to drain excess fluid. The other end of the tube is connected to the abdomen or another area in the body that can absorb the excess CSF.

After the shunt is placed, the patient must be monitored closely and may require multiple procedures. Potential issues after shunt placement include:

• Infection
• Blocked pathways
• Mechanical problems
• Insufficient length of the shunt

Another treatment is ETV (endoscopic third ventriculostomy). This procedure uses fiber-optic technology. The doctor directs a small camera into the baby's brain and creates a hole in the ventricle using special tools to allow CSF to exit. The brain fluid then flows through this hole and is absorbed into the bloodstream.

ETV also carries risks such as the sudden closure of the ventricular hole, which can be life-threatening. Infections, fever, or bleeding may also occur.

Even after treatment, congenital hydrocephalus can affect physical and intellectual development. The child may need rehabilitation and special education. However, there is hope for the child to lead a normal life with minimal limitations.

Consult with doctors, nurses, or therapists regarding the care and treatment for your child. If medications are involved, ensure the child takes them as prescribed. Keep track of regular check-up schedules to monitor the child's development effectively.

Complications

Untreated hydrocephalus can lead to complications such as intellectual, developmental, and physical disabilities, including learning disorders, speech disorders, memory problems, social skill difficulties, vision impairments such as strabismus and decreased visual acuity, physical coordination issues, or epilepsy. Severe hydrocephalus can be life-threatening. Properly managed mild cases can have minimal complications.

Prevention

There is no known way to prevent congenital hydrocephalus, but its risks can be reduced. Pregnant women should consume a balanced diet essential for fetal brain development and eat cooked foods to prevent foodborne infections. Other viral infections should be prevented by maintaining a clean and healthy lifestyle.

Regular prenatal check-ups, including ultrasound examinations, are crucial. This reduces the risk of premature birth, which is associated with a higher risk of hydrocephalus. Early detection of developmental issues through regular check-ups allows for timely intervention, reducing the severity and progression of symptoms.

When to see a doctor?

Take your baby to the emergency room immediately if they exhibit the following signs and symptoms:

• High-pitched crying
• Sucking or feeding difficulties
• Repeated vomiting without an obvious cause
• Seizures

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