What is Hydrocephalus?

What is Hydrocephalus?

Table of Contents

• Why Does Hydrocephalus Occur?
• What are the Symptoms of Hydrocephalus?
• How is Hydrocephalus Treated?

In its most general definition, hydrocephalithemia describes a condition in which the amount of water in the head increases and the first thing that comes to mind is head enlargement. Inside our head, we have cavities that we think of as interconnected caverns. We call these “ventricles” or “ventricles”. The largest of these is the “lateral ventricle”. It would be wrong to think of the water inside our head as water as we know it. This water is called “cerebrospinal fluid” and it has many functions. Its most important function is to protect the brain in the event of a violent impact. This fluid also contains nutrients, just like our blood.

Most of the cerebrospinal fluid (CSF) is made in the choroid plexus, a moss-like organ in the ventricles, while some is made in the brain tissue and spinal cord. The moss-like choroid plexuses are present in all ventricles and are mainly responsible for CSF production. About half a liter of CSF is produced per day and the same amount is absorbed. The CSF from the lateral ventricles on both sides flows through a small window (foramen Monro) into the third ventricle in the middle of the brain and then continues through a thin, 1 cm long canal into another cavity called the fourth ventricle. This flow continues all the way to the spinal cord center.

The CSF exits through the holes in the fourth ventricle, circulates around the spinal cord and the brain and returns to the large veins on the surface of the brain, where it is absorbed by special tissues (arachnoid villi). Now it will be much easier to recognize hydrocephalus. The scientific definition of hydrocephalus is an increase in the pressure and amount of cerebrospinal fluid with enlargement of the brain cavities (ventricles).

Why Does Hydrocephalus Occur?

In the vast majority of existing patients, hydrocephalus is caused by a blockage at any point in the circulatory pathway of the cerebrospinal fluid. The blockage may be in the holes or canal connecting the ventricles or in the last point of absorption. This blockage can be caused by a head injury, infection or tumor. 

The causes of hydrocephalus can also be divided into congenital, or “congenital”, or acquired, or “acquired”. Congenital hydrocephalus can be associated with diseases such as myelomeningocele. Acquired hydrocephalus can also develop for three reasons: First, overproduction of cerebrospinal fluid. This is usually due to a tumor. Secondly, there is an obstruction in the pathways through which the cerebrospinal fluid circulates. The cause of the obstruction is infections such as meningitis-encephalitis and bleeding due to trauma. This type of hydrocephalus caused by obstruction of fluid flow is also called “non-communicated” hydrocephalus. The third cause is a defect in the absorption of cerebrospinal fluid. This type of hydrocephalus is referred to as “communicating” hydrocephalus. Briefly summarize the causes of hydrocephalus;

• Myelomeningocele in Spina Bifida (the spinal cord does not close but remains open in the womb)
• Stenosis-obstruction of the water canal between the third ventricle and the fourth ventricle (Aqueductal stenosis-obstruction)
• Herniation of the cerebellum and/or brain stem from the skull into the spinal canal (Chiari malformations)
• Fluid-filled sacs that narrow or block CSF pathways (Arachnoid cysts)
• Brain, cerebellum and brain stem tumors
• After meningitis and similar infections
• After bleeding into the brain cavities or under the meninges
• Tumor of the CSF-producing organ
• Blocked CSF flow under the meninges after bleeding, infection or inflammation
• It may present as genetic or familial hydrocephalus.

Symptoms of hydrocephalus may vary according to the age of the child and the degree of increase in cerebrospinal fluid. 

What are the Symptoms of Hydrocephalus?

• Growth around the head
• Headache due to increased intracranial pressure
• Widening and tension in the fontanel
• Vomiting and Weight loss
• A high-pitched cry
• Double vision
• Decreases in school success
• Vascular prominence in the head
• Restlessness
• Problems in maintaining balance
• Visual disturbances
• Sight of the setting sun in the eyes (inability to look upwards)
• Speech and gait retardation

How is Hydrocephalus Treated?

Early detection of hydrocephalus is important for treatment. Today, hydrocephalus treatment planning; If the cause of the obstruction is a tumor, an intervention can be made for it, or the excess fluid collected is directed through an appropriate way to be absorbed from another part of the body. This diversion is done with devices called “shunts”.

Shunt: It consists of a silicone tube, the thickness of which is as thick as the plastic part that holds the ink in a ballpoint pen.

The shunt consists of three parts:

1. Ventricular catheter (tube)

2. Valve (pump)

3. Distal catheter (tube to the abdominal cavity or heart) that continues after the valve or pump

The feature of the valve is that it allows CSF flow in one direction. There are different shunt systems that can be selected according to the existing problems in the child.

1. Ventriculo-Peritoneal (VP) Shunt: Here, excess fluid in the head is directed under the skin into the abdominal cavity. The fluid is absorbed by the peritoneum. This can be compared to a paper napkin absorbing water on a table. A tube inserted into the lateral ventricle is passed under the skin through the neck and trunk and directed into the abdominal cavity. It is simple to administer and easier to fix if there is a blockage. A valve is added to the system that allows it to work when the pressure of the fluid in the head exceeds a certain level. Depending on the surgeon’s preference, a pump can also be added to remove CSF and pump it when necessary. In summary, valves are high, medium and low pressure. The most preferred shunt type worldwide is the ventriculo-peritoneal shunt. It has fewer problems and is less dangerous than other shunt methods.
2. Ventriculo-Atrial (VA) Shunt: Excess fluid is directed into one of the veins leading to the heart instead of the abdomen. A one-way valve (pump) system is required to prevent the blood in the veins from backing up, and a thin plastic tube that continues after the pump is advanced in a vein to the right atrium of the heart. It is less preferred because its complications are more serious than the ventriculo-peritoneal shunt (injury, blockage, chronic infection in the connecting vessel) and it is very difficult to replace. Currently, VA shunt is used as an alternative to VP shunt if there is an intra-abdominal problem.
3. Ventriculo-pleural (VPl) Shunt: In this method, the fluid in the brain is drained between the two leaves of the membrane (pleura) around the lung through a tube and valve. Ventriculo-pleural shunt is another method that can be considered in cases where VP shunt cannot be applied. Ventriculo-pleural shunting is not used in children younger than 5 or 6 years of age. Because the accumulated fluid may compress the lungs and cause respiratory distress. Other cases where this method is not suitable are those who have fluid accumulation in the chest cavity due to another cause and therefore have respiratory problems, small children due to the small chest cage and narrow absorption area, and patients with renal-heart failure.
4. Lumbo-Peritoneal (LP) Shunt: Lumbo-peritoneal shunts can be used in the treatment of communicated hydrocephalus. LP shunts are not widely accepted and it is not possible to compare the differences in long-term success between them and ventriculo-peritoneal shunts. CSF in the spinal cord membrane between the vertebrae in the lower back is drained into the abdominal cavity through a catheter inserted into this membrane. A disadvantage of the lumbo-peritoneal shunt is the risk of late-onset, long-lasting herniation of the small round tonsil-like part of the lower part of the cerebellum (chronic symptomatic cerebellar tonsillar herniation).

In all shunt methods, when setbacks occur during the development of the child, the shunt must be renewed and the problems must be eliminated surgically, which we call revision. In short, like various car models, there are different types and models of shunts. However, they are all used for the same purpose. Which type of shunt to choose depends on the physician’s preference and the patient’s problems. Although the shunt insertion procedure is short and not difficult, it is performed in the operating room under sterile conditions and under general anesthesia. After the shunt insertion, the child is hospitalized to check the functioning of the shunt and to check for any side effects of anesthesia. During hospitalization, the child is monitored and recorded by the nurse.