HYDROCEPHALUS: A patient guide by a Neurosurgeon

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Hydrocephalus meaning | What is Hydrocephalus?

 

Hydro means Water, Cephalus means Head. Hydrocephalus means excess water in the head.

Hydrocephalus is the abnormal increase in the Cerebrospinal Fluid ( the nutritive fluid present normally within the brain and spinal cord). When Neurosurgeons talk of hydrocephalus, they are generally referring to the increase in the size of the spaces within our brains (called ventricles) that normally contain the most amount of the Cerebrospinal fluid (a process called ventriculomegaly).

 

Hydrocephalus Pathophysiology in simple non-medical terms:

 

Hydrocephalus is often difficult for a non-medical person to imagine. I generally explain this condition to my patients in the following way:

 

1. There is a nutritive fluid called CSF present within the brain of every person, including you and me.

2. The largest amount of CSF is present within normal spaces in the brain called Ventricles.

3. In hydrocephalus, the CSF present in the ventricles increases in amount, and the ventricles start to swell, like balloons filled with water.

4. This increases the pressure within the brain, which can be very dangerous to a person.

 

I tell my patient to imagine the ventricular system of the brain like a sink with a draining pipeline. If the pipeline gets blocked by dirt within the pipe or by something pressing the pipe from the outside, water will fill up the sink until it overflows. This the basis for-

(NON COMMUNICATING HYDROCEPHALUS).

 

If theres a block in the main drainage where the sink drains, then the water wont be able to drain out of the pipe, again filling up the sink. And if too much water is dumped into the sink, the draining pipe might not be large enough to drain all the excess water, and the sink would always be full. This is the basis for-

(COMMUNICATING HYDROCEPHALUS).

 

These are the same mechanisms by which hydrocephalus happens in the brain, with the ventricles being the sink and the drainage pathway being the pipe and the outer coverings of the brain being the final large drain through which CSF is absorbed.

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Hydrocephalus Causes | What is the cause for hydrocephalus? | Hydrocephalus pathophysiology continued

 

Hydrocephalus is usually caused by the blockage of the flow or absorption of normal Cerebrospinal Fluid (CSF) in the brain. In some rare cases Hydrocephalus can be caused by excessive production of CSF.

 

Some common causes for hydrocephalus are:

 

Congenital hydrocephalus due to Aqueductal Stenosis: | Hydrocephalus in babies:

 

The most common cause of blockage of CSF is due to a block at a point in the normal CSF pathway called the Aqueduct of Sylvius. This kind of block occurs most commonly in children and may even be detected in the womb before the child is born. It is one of the most common causes of hydrocephalus in children, sometimes leading to the child having a very large head. When people speak about childhood hydrocephalus, they are usually referring to these kinds of patients.

 

Hydrocephalus due to Brain infections:

 

Infections of the brain are an important cause of hydrocephalus. These include bacterial infections (Bacterial meningitis and ventriculitis) and Tuberculosis of the brain (TB meningitis, which is a very important cause of hydrocephalus in developing countries). In infections, there may be a blockage of the normal pathway of CSF or in the absorption of CSF due to debris and degeneration of infected tissue.

 

Hydrocephalus due to external compression:

 

This kind of hydrocephalus is seen in patients suffering from brain hemorrhage of brain tumors. A hemorrhage or tumor might compress the pathway of the CSF from outside, blocking the pathway and causing a pooling of the CSF and increase in the size of the ventricle.

 

Hydrocephalus due to internal blockage by blood or tumor: This occurs when there is bleeding within the ventricular system or there is a tumor growing within the ventricular spaces which blocks the flow of CSF.

 

Hydrocephalus due to increased production of CSF: In rare cases, the production of the CSF within the ventricular system is increased. This happens when the patient suffers from a tumor called Choroid Plexus tumor.

 

Normal pressure Hydrocephalus: 

 

This disease is a unique condition occuring in older patients. In this condition, there is an increase in the size of the ventricles, but the ballooning might not be so much. Patients generally show symptoms that might be present in other diseases as well, such as memory disturbances, difficulty walking and urinary complaints. Because of the similarity of complaints with diseases such as Alzheimers, the diagnosis of this condition can become tricky, but it remains the only form of dementia that has a surgical treatment, with well selected patients showing significant improvement with shunt surgery.

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Hydrocephalus diagnosis | How is hydrocephalus diagnosed?

 

The most common investigation to diagnose hydrocephalus is a CT scan of the head. But other investigations have an important place:

 

1. CT head for hydrocephalus: Most commonly done scan. It helps to see enlarged ventricles, can help diagnose the kind of hydrocephalus and helps in surgical planning and management.

2. MRI brain: This scan also shows the enlarged ventricles, but can further help in seeing the cause for the hydrocephalus like brain hemorrhage or brain tumors or signs of infection. It also helps in surgical planning, specially in patients who need endoscopic surgery for hydrocephalus. It is particularly used in very small children with hydrocephalus, in whom the radiation from CT scans can be harmful. An MRI uses magnetic waves and not radiation, so it is preferable in very small children to prevent radiation exposure.

 3.  Ultrasound of the skull and Ultrasound during pregnancy for Hydrocephalus: In very small children, an ultrasound can be done         through the skull, as in these patients, there are spaces in between the bones that can be an entry for ultrasound wave                     transmission. It helps give an idea if hydrocephalus is present, but a CT or MRI is necessary for operative planning.

 

       Another advantage of Ultrasound scans is when the child is in the uterus. During these ante-natal scans hydrocephalus can be        diagnosed in the unborn child as well, and depending on the number of weeks the pregnancy has progressed, various                    management options are discussed with the parents.

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Hydrocephalus treatment | How is hydrocephalus treated? | Surgery for hydrocephalus

 

Medical treatment for hydrocephalus

 

Hydrocephalus is essentially a surgical problem. But medical therapy can buy the patient precious time and help support management by treating the underlying cause in infective hydrocephalus. Medical treatment includes:

 

1. Acetazolamide, Frusemide and Mannitol: These drugs may be used to decrease the production of CSF or decrease the fluid content of the brain, buying time for the patient by decreasing the pressure effects of the hydrocephalus.

2. Antibiotics and Anti-tubercular medicines: These drugs control and remove infection from the brain. For hydrocephalus due to infections, while surgery can help decrease the pressure due to the hydrocephalus, the final cure can only be provided by anti-biotics.

 

Hydrocephalus surgery | What is surgery for hydrocephalus? | Hydrocephalus Shunt | ETV for hydrocephalus

 

Surgery is the main treatment for hydrocephalus.

 

There are two main surgeries done for the long-term treatment of hydrocephalus:

 

Hydrocephalus Shunt surgery | VP shunt surgery :

 

 

In this type of surgery an artificial pipe is placed that connects the CSF filled ventricles with a different large space in the body, most commonly the abdomen (the cavity that contains a person’s stomach and intestines). Once the CSF drains into these large spaces, it is safely absorbed into the body, decreasing the pressure of the CSF in the brain. In this surgery the piping system and the valve that regulates the flow of CSF are all placed under the skin. The whole system is therefore internal.

 

Endoscopic Third Ventriculostomy (ETV) :

 

This type of surgery is done less commonly as less neurosurgeons are trained in endoscopic techniques and selection for patients fit for this kind of surgery is lesser than for Shunt surgery, which can generally be used in all patients. The major benefit of this Endoscopic surgery is that it leads to the creation of a natural alternate pathway for CSF in the brain and for patients in whom it is successful, there is no need for an artificial implant, which decreases the chances of infection and dependancy on an artificial tube that can become blocked or can malfuntion. However, as mentioned, not all patients are suitable for this kind of procedure, not all patients who have the procedure have a successful result and ETV is related with it’s own technical complications.

 

Other than these two surgeries, for emergency purposes or in cases where the hydrocephalus is related to active infection in the brain, a neurosurgeon might perform two other temporary procedures:

 

External ventricular Drain placement (EVD):

 

A small hole in made in the skull and a drain is placed in the ballooned ventricles which connects directly with a drain pipe and a bag. This kind of EVD can only be kept for a limited period of time, and then needs to be changed by a fresh EVD.

 

Ommaya Reservoir placement:

 

Like an EVD, a small hole in made in the skull and a drain pipe is placed into the ballooned ventricles, but this pipe is connected to a plastic chamber, and the setup is covered under the skin. This allows the neurosurgeon to drain the ventricle at ease, without any further anesthesia whenever the situation demands, by inserting a needle into the reservoir chamber. When drainage is not needed, the Ommaya reservoir stays in place and is not taken out, unless there’s a problem.

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