Introduction:
The term ‘hydrocephalus’ originates from the Greek words ‘hydro’ meaning water and ‘cephalus’ meaning head. The word ‘congenital’ means that the condition is present at birth. Cerebrospinal fluid or CSF is a clear fluid present around the brain and spinal cord that brings nutrients and removes toxins or waste from the tissues. It gets absorbed into the blood. In hydrocephalus, there is a mismatch in the production and absorption of CSF into the blood which results in its accumulation around the brain and increases the pressure in the brain.
How Common Is Congenital Hydrocephalus?
Congenital hydrocephalus occurs in one out of every 1000 newborn babies. A rare form of hydrocephalus called acquired hydrocephalus develops after birth following an injury, tumor, or disease that interferes with the absorption of cerebrospinal fluid.
Who Are At Risk Of Developing Congenital Hydrocephalus?
Premature babies who are born before 37 weeks of gestation are at a higher risk of developing congenital hydrocephalus. Few premature babies can have bleeding in the brain which can obstruct the entry and absorption of cerebrospinal fluid causing hydrocephalus. Babies born with spina bifida (a condition in which a developing spinal cord in a baby fails to develop properly and a part of it is exposed) are susceptible to developing congenital hydrocephalus.
What Are The Conditions Linked To Hydrocephalus?
The three conditions which cause an imbalance in the cerebrospinal fluid leading to hydrocephalus are:
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Excess production of CSF in the spaces of the brain called ventricles where CSF is produced.
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Obstruction in the flow of CSF leads to its accumulation in the brain.
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The inability of the bloodstream to absorb the CSF.
What Are The Reasons For Congenital Hydrocephalus?
Various causes for congenital hydrocephalus include:
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Abnormalities In The Central Nervous System: Abnormalities in the development of the central nervous system can hinder or interfere with the flow of cerebrospinal fluid.
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Infections: The presence of infections such as rubella or syphilis in the uterus during pregnancy can cause inflammation of the brain tissues in the fetus.
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Aqueductal Stenosis: In this condition, the ducts of the communicating network of the brain called ventricles may be partially or completely blocked as a result of infection, hemorrhage, or tumor affecting the flow of CSF.
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Arachnoid Cysts: Fluid-filled sacs in the brain called arachnoid cysts can hinder the flow of CSF.
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Dandy-Walker Syndrome: It is a condition in which the cerebellum (part of the brain that controls movement and balance) of the brain does not develop normally and one ventricle of the brain is larger than the others because of the narrowing or blockage of the interconnecting pathways causing CSF buildup.
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Chiari Malformation: A problem at the point of union of the brain and the spinal cord is called Chiari malformation. In this, the lower end of the brain can push itself into the spinal cord causing an obstruction.
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Mutation: Mutation (a genetic change) in the X-chromosome (L1CAM gene) is called X-linked hydrocephalus.
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Craniosynostosis: Congenital hydrocephalus can also occur in craniosynostosis in which the bones of the skull fuse before the brain is completely developed.
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Hydranencephaly: It is a rare condition in which the cerebral hemispheres of the brain are absent and replaced with fluid-filled sacs containing CSF.
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Schizencephaly: It is an extremely rare condition of the brain in which there are abnormal slits or clefts in the cerebral hemispheres of the brain that can affect the flow of CSF.
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Vein Of Galen Malformation: It is a rare abnormality of the blood vessels in the brain in which misshapen arteries are directly connected with the veins instead of the capillaries that retards blood flow and increases blood flow into the veins. This condition secondarily affects the absorption of CSF.
What Are The Symptoms Of Congenital Hydrocephalus?
The symptoms of congenital hydrocephalus are:
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Downward deflection of the eyes is called ‘sunsetting’.
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Irritability.
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Sleepiness.
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Seizures (sudden, uncontrollable electrical disturbance in the brain that affects behavior, movements, feelings, and consciousness).
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Abnormally enlarged head that is not proportionate with the growth of other parts of the body.
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Fussiness.
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Poor appetite.
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The soft spot on the baby’s head called fontanelle tends to bulge out or feel firm. The areas between the skull bones called sutures may be enlarged.
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Veins in the scalp appear swollen.
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Developmental delays.
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Vision problems.
How Is Congenital Hydrocephalus Diagnosed?
Congenital hydrocephalus can be diagnosed before or after birth as follows:
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Diagnosis Before Birth: The condition can be diagnosed early during three to four months of pregnancy. Abnormal expansion of the brain cavity can be diagnosed during the fifth or sixth month of pregnancy. Tests to diagnose congenital hydrocephalus before birth are:
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Amniocentesis: Intrauterine fluid is aspirated using a needle to detect other abnormal conditions that may be associated with hydrocephalus.
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Ultrasound: Ultrasounds may show the presence of abnormal fluid collection but not the blockage.
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Diagnosis After Birth: Diagnosis of hydrocephalus is done mostly after birth and involves thorough physical examination, history of hydrocephalus in family members, imaging techniques like computed tomography (CT), ultrasound, magnetic resonance imaging (MRI), and pressure-monitoring techniques.
What Are The Treatment Options For Congenital Hydrocephalus?
The treatment will be planned by the doctor based on the baby’s gestational age, health conditions, medical history, type, cause of the condition, baby’s tolerance to therapies, medications, or procedures, the outcome of the treatment, and parent’s consent. The treatment aims to drain the excess CSF and reduce the intracranial pressure in the baby’s head. Even if the condition is diagnosed before birth, treatment is done after birth.
The following are the various treatment modalities:
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Ventriculoperitoneal (VP) Shunt Surgery: In this method, the tube inserted extends from the brain’s ventricles into the peritoneal cavity (the cavity in the abdomen that consists of the intestines, stomach, and liver) where the excess CSF is drained and absorbed into the blood. The shunt may also be placed in the heart chamber or the space surrounding the lungs. The shunt may be changed if the child grows and requires a large shunt or if the tube is infected or not working.
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Endoscopic Third Ventricular (ETV) Surgery: In this procedure, a tiny hole is made at the bottom of the ventricle in the brain to channel the excess CSF so that it can drain and get absorbed into the bloodstream.
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Lumbar Puncture: Emergencies in which there is a necessity to drain the excess CSF before placing the shunt involve a procedure in which a lumbar puncture or a spinal tap may be necessary.
Developmental delays and intellectual and physical disabilities can be treated after surgery through speech therapy to correct speech delays, physiotherapy to improve motor skills, early intervention programs, and so on.
What Are The Complications Of Surgery For Congenital Hydrocephalus?
The shunts have to be monitored carefully through frequent follow-ups with the health care provider as there can be chances of infections, blocked tubes, mechanical problems, need for larger shunts, and so on. In the endoscopic third ventricular surgery, the hole can close on its own which can cause the symptoms of hydrocephalus to reoccur and can be life-threatening. Infection, fever, and bleeding can also occur.
Can Congenital Hydrocephalus Be Prevented?
Congenital hydrocephalus cannot be prevented but parents can be careful to prevent head injuries after birth by following simple measures such as fastening the seatbelts around the child while traveling, ensuring that the child wears helmets during sports or other activities, childproofing the house to prevent injuries from falls and so on.
Conclusion:
Congenital hydrocephalus can be diagnosed in pregnancy but treatment is commenced after delivery. Early detection of the signs and treatment before 4 months of age is mandatory to prevent it from being life-threatening. With proper treatment and regular follow-ups, the individual can lead a normal life. Any abnormal signs after surgery should not be ignored and the doctor must be consulted immediately. Cognitive and physical development may be affected which should be corrected by seeking appropriate medical help.
