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HYDROCEPHALUS - FACTSHEET

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p.4 What is Hydrocephalus?

p.5 Causes of Hydrocephalus

p.7 How is Hydrocephalus treated?

p.7 Endoscopic 3rd Ventriculostomy (ETV)p.8 Shunt

p.10 Can Hydrocephalus be prevented?

p.12 Living with Hydrocephalus

p.13 Hydrocephalus in developing countries

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What is Hydrocephalus?

Hydrocephalus is a condition in which the primary characteristic is excessive accumulation of fluid in the brain. Although hydrocephalus was once known as “water on the brain,” the “water” is actually cerebrospinal fluid (CSF) - a clear fluid surrounding the brain and spinal cord. The excessive accumulation of CSF results in an abnormal dilation of the spaces in the brain called ventricles. This dilation causes potentially harmful pressure on the tissues of the brain.

Hydrocephalus is the buildup of too much cerebrospinal fluid in the brain. Normally, this fluid cushions the brain. When there is too much, though, it puts harmful pressure on the brain that tends to become enlarged, sometimes with little or no increase in intracranial pressure (ICP).

The ventricular system is made up of four ventricles connected by narrow passages. Normally, the cerebro-spinal fuid (CSF) flows through the ventricles, exits into cisterns (closed spaces that serve as reservoirs) at the base of the brain, bathes the surfaces of the brain and spinal cord, and then reabsorbs into the bloodstream. CSF has three important life-sustaining functions: 1. to keep the brain tissue buoyant,

acting as a cushion or “shock absorber”;

2. to act as the vehicle for delivering nutrients to the brain and removing waste;

3. to flow between the cranium and spine and compensate for changes in intracranial blood volume (the amount of blood within the brain).

The balance between production and absorption of CSF is critically important. Because CSF is made continuously, medical conditions that block its normal flow or absorption will result in an over-accumulation of CSF.

The resulting pressure of the fluid against brain tissue is what causes hydrocephalus. Hydrocephalus is sometimes referred to as ‘water on the brain’. A watery fluid, known as cerebro-spinal fluid or CSF, is produced continuously inside each of the four spaces or ventricles inside the brain.

The CSF normally flows through narrow pathways from one ventricle to the next, then out across the outside of the brain and down the spinal cord. The CSF is absorbed into the bloodstream and recirculates.

The amount and pressure are normally kept within a fairly narrow range. If the drainage pathways are blocked at any point, the fluid accumulates in the ventricles inside the brain, causing them to swell - resulting in compression of surrounding tissue. In babies and infants, the head will enlarge. In older children and adults, the head size cannot increase as the bones which form the skull are completely joined together.

Causes of Hydrocephalus

Hydrocephalus is a condition caused by the inability of CSF to drain into the bloodstream. There are many reasons why this can happen:

Congenital Hydrocephalus

This means that Hydrocephalus is present at birth. It is important to remember that this term does not imply that it is hereditary. Often the exact cause of congenital Hydrocephalus cannot be determined. Prematurity

Babies born prematurely are at risk of developing Hydrocephalus. A baby born early is far more vulnerable than one which goes the full term since it is still developing. The area which lies just beneath the lining of the ventricles in the brain is particularly important - because of the activity in this area it has a plentiful of blood supply. Its blood vessels are very fragile and can easily burst if the baby suffers too large a swing in blood pressure or becomes severely ill from other causes.

If these complications do occur, then the baby is at risk of developing a haemorrhage from rupture of the fragile vessels. This can lead to a blood clot developing, which in some cases is big enough to break through the wall of the ventricle. Should the clot block the flow of CSF, the baby will develop Hydrocephalus. The blockage may be temporary or permanent. Even if a blood clot does not develop, the blood cells from the haemorrhage can cause blockage.

Spina Bifida

Most babies born with Spina Bifida have Hydrocephalus. In addition to the lesion in the spinal cord, there are abnormalities in the structure of certain parts of the brain which develop before birth. This prevents proper drainage of the CSF. The increase in pressure can compress the abnormal parts of the brain even further. Other forms

Forms of brain haemorrhage, including those occurring in adults ("stroke"), can result in this type of post-haemorrhagic Hydrocephalus. Meningitis

This is an infection of the membranes covering the brain. The inflammation and debris from this infection block the drainage pathways resulting in Hydrocephalus. Meningitis can occur at any age but it is more common in children. The incidence of one form, haemophilus meningitis, has been drastically reduced by the HIB vaccine. Dandy Walker Cysts

There is a particular group of disorders involving the formation of fluid-filled cysts in the CSF system (for example Dandy Walker cysts). In these cases, Hydrocephalus is often developed due to the pressure on the surrounding tissues by the enlarging cyst.

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Tumours

Tumours of the brain cause compression and swelling of surrounding tissues, resulting in poor drainage of CSF. In the treatment of brain tumours, it is often necessary to include measures to control Hydrocephalus, which may only be temporary. Genetic

In very rare circumstances, Hydrocephalus is due to hereditary factors, which may affect future generations.

How is Hydrocephalus treated?

Some forms of Hydrocephalus require no specific treatment. Other forms are temporary and do not require long-term treatment. However, most forms do require treatment, and this is usually surgical. Drugs have been used for many years but they may have unpleasant side effects and are often not successful.

The usual treatment is to insert a shunting device. It is important to note that this does not ‘cure’ the Hydrocephalus and damage to the brain tissue remains. Shunting controls the pressure by draining excess CSF, so preventing the condition from becoming worse. Symptoms caused by raised pressure usually improve but other problems of brain damage will remain.

An alternative treatment may be third ventriculostomy. This treatment, if successful, avoids the need for a shunt. However, not all types of Hydrocephalus can be treated by this method and it is not available in all neurosurgical units.

Can hydrocephalus be cured?

There is no cure for hydrocephalus. In most cases, it is a condition that is present for life, except when it is the result of a brain tumour. In this case, it may be possible to remove the tumour, and allow the cerebrospinal fluid to flow.

Endoscopic 3rd Ventricu-lostomy (ETV)

Recently neuroendoscopy (telescopic surgery) makes treatment of Hydrocephalus possible without shunting in two thirds of patients (the success rate depends on the etiology (cause of) the Hydrocephalus and varies between one quarter to nearly one hundred percent). Management of Hydrocephalus by “Third Ventriculostomy” creates a natural bypass within the brain allowing the fluid to drain. This is a procedure that does not have the complications of shunt insertion. Infection is rare and the morbidity is very low. This low morbidity operation is a valid treatment for Hydrocephalus in the difficult conditions of developing countries where follow-up is inconsistent and retrieval of patients in case of complications is near to impossible.

Re-inventing the wheel or Third Ventriculostomy: Dr. M. Vloeberghs explains the background and use of Third Ventriculostomy in the treatment of hydrocephalus.

ETV - initial experience at the CURE Children’s Hopsital of Uganda: Dr. B. Warf, cooperating with IF in the project in Mbale (Uganda) made a research on his initial experiences with Third Ventriculostomy in developing countries.

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Shunt

What is a Shunt?

A shunt is simply a device which diverts the accumulated CSF from the obstructed pathways and returns it to the bloodstream. It consists of a system of tubes with a valve to control the rate of drainage and prevent back-flow. It is inserted surgically so that the upper end is in a ventricle of the brain and the lower end leads either into the heart (ventriculo-atrial) or into the abdomen (ventriculo-peritoneal). The device is completely enclosed so that all of it is inside the body. The fluid which is drained into the abdomen passes from there into the bloodstream. Other drainage sites such as the outer lining of the lungs (ventriculo-pleural shunt) can also be used.

A shunt consists of: A Catheter: hollow flexible tube inserted into a ventricle in the brain or into the space around the spinal cord, depending on the type of hydrocephalus that the child has. A valve: which controls the amount, pressure and direction of CSF flow (so that CSF can only flow away from the brain). A tube leading from the valve under the lining of the abdominal cavity called the peritoneum where the CSF can be absorbed.

Possible complications

In most cases, the shunts are intended to stay in place for life, though alterations or revisions might become necessary from time to time. The tube or catheter may become too short as the individual

grows and an operation to lengthen it might be necessary. Occasionally, as with any implant, there can be mechanical failure. Also, it is important to be aware that problems can occur with blockage or infection of the shunt. What symptoms should be looked for?

These vary enormously between individuals. Previous personal experience of a shunt problem is usually a reliable guide as to what to look for. Possible signs of acute shunt blockage may include: vomiting, headache, dizziness, photophobia (sensitivity to light) and other visual disturbances, drowsiness and fits. Possible signs of chronic shunt blockage may include: fatigue, general malaise, visuo-perceptual problems, behavioural changes, decline in academic performance, being just ‘not right’ from the carer’s point of view.

Medical advice should be sought from your neurosurgical unit if a shunt blockage is suspected, within four hours of acute symptoms occurring.

In shunt infections, symptoms vary with the route of drainage. In ventriculo-peritoneal shunts, the symptoms often resemble those of a blockage. This is because the shunt becomes infected and the lower catheter is very often then sealed off by tissue. There may be accompanying fever and abdominal pain or discomfort.

In ventriculo-atrial shunt infections, fever is present in most cases though often intermittently. Anaemia is frequently

present, and sometimes skin rashes along with joint pains. In contrast to ventriculo-peritoneal shunts, such infections may not appear for months or years after the operation when they were contracted. Various tests can be carried out for shunt infections and medical advice should always be sought if an infection is suspected.

How are shunt problems treated?

Shunt blockages which are causing illness usually require an operation to replace or adjust the offending part of the shunt. Shunt infections are usually treated by removal of the whole shunt and a course of antibiotics before insertion of a new system. Modern approaches to antibiotic therapy mean that such treatment can be expected to succeed in most cases.

Hydrocephalus and fits

Richard Hayward, consultant neurosurgeon, writes:

“Patients with Hydrocephalus sometimes have fits. The fits are not due to the Hydrocephalus itself but are usually associated with an underlying cause (meningitis, abnormal development of the brain, neonatal haemorrhage etc). As a general rule, fits in patients with Hydrocephalus should be treated in the same way as those that occur in children who do not have Hydrocephalus.”

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Can Hydrocephalus be prevented?

Hydrocephalus is not a preventable condition. However, there are ways to reduce the risk of Hydrocephalus:

• If you're pregnant, get regular prenatal care. Following your doctor's recommended schedule for checkups during pregnancy can reduce your risk of premature labor, which places your baby at risk of hydrocephalus and other complications.

• Protect against infectious illness. Follow the recommended vaccination and screening schedules for your age and sex. Preventing and promptly treating the infections and other illnesses associated with hydrocephalus may reduce your risk.

To prevent head injury:

• Use appropriate safety equipment. For babies and children, use a properly installed, age- and size-appropriate child safety seat on all car trips. Make sure all your baby equipment — crib, stroller, swing, highchair — meets all safety standards and is properly adjusted for your baby's size and development. Children and adults should wear a helmet while riding a bicycle, skateboard, motorcycle, snowmobile or all-terrain vehicle.

• Always wear a seat belt in a motor vehicle. Small children should be secured in child safety seats or booster seats. Depending on their size, older children may be adequately restrained with seat belts.

Should you be vaccinated against meningitis?

Ask your doctor if you or your child should receive a vaccine against meningitis, once a common cause of hydrocephalus. The Centers for Disease Control and Prevention recommends meningitis vaccination for preteen children and boosters for teenagers. It's also recommended for younger children and adults who may be at increased risk of meningitis for any of the following reasons:

• Traveling to countries where meningitis is common

• Having an immune system disorder called terminal complement deficiency

• Having a damaged spleen or having had the spleen removed

• Living in a college dormitory• Joining the military.

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Living with Hydrocephalus

A person with hydrocephalus can have some or all of the following difficulties, however, the degree to which the hydrocephalus affects any individual varies greatly from minimal to quite severe, and often varies from day to day.

Sometimes children with hydrocephalus can be seen as 'naughty' or 'disruptive', but often at least some of the difficulties they have can be due to their underlying learning difficulties, or to the cause of the hydrocephalus. Each child will also have 'good' and 'bad' days, just like other children.

Effects can include:

Fine motor skills• May have impaired dexterity affecting

drawing and sports• Handwriting can often be untidy

Spatial awareness• Poor eye hand co ordination, poor

sense of direction, unsure balance

Short term memory impairment• Difficulty following detailed sequence

of instructions• Difficulties learning new information• Forgetting things they have learned• Difficulties with comprehension

Social• Talking a lot and repetitive speech• Difficultly making and keeping friends• Content of conversation is superficial

but well articulated• Use social jargon and words without

fully understanding their meaning• Over-familiar manner

• Inappropriate introduction of personal experience during conversation

Short attention span• May experience difficulty keeping to

task• They may not complete tasks,

daydream and have difficulty following things when there is lots going on

Diminished motivation/initiation• May sit and wait for instructions. Often

this is misinterpreted as laziness

Executive functions• Not thinking before acting, poor

planning and organisation

Inability to generalise• Difficulty transferring concepts from

one situation to a different one, especially in mathematics

• Difficulty transferring problem solving experiences from one situation to another

Altered concept of time• No inclination to hurry• Altered thinking skills become

more evident for children living with hydrocephalus when they enter high school. They are expected to become more independent in their learning, and manage changing routines and be flexible

Hydrocephalus in developing countries

In developing countries, causes of Hydrocephalus could be related to, or exacerbated by poverty and lack of proper healthcare. Undernourished mother run a higher risk of having premature babies, which, in turn, run a higher risk of having haemorrhaging. Meningitis in these countries is often the result of postnatal infections caused by poor delivery techniques or conditions. The inadequate treatment of these infections can result in Hydrocephalus. Treatment of Hydrocephalus in developing countries

Hydrocephalus is most commonly treated by placement of a ventriculoperitoneal shunt (VP shunt). Shunts may be accompanied by a number of problems. They are prone to infection, especially within the first 3 months after operation. Shunt infections are life threatening and expensive and treatment is time-consuming. VP shunts are also prone to malfunction. One recent large multi-institutional study found that 40% of patients required a shunt revision within 2 years of initial shunt placement. Given a lifetime of shunt dependency, these problems are especially dangerous when access to competent care is difficult. An alternative treatment is endoscopic third ventriculostomy (ETV). This treatment is minimally invasive. It also avoids infection, shunt dependency, the potential for shunt malfunction, and the cost of a shunt. ETV perforates the lower section of the third ventricle, which allows Cerebro-spinal fluid (CSF) to escape

from the ventricles into the subarachnoid spaces, from which it is subsequently absorbed. If the hydrocephalus is caused by an obstruction to CSF flow within the ventricles, obstruction to the normal CSF outflow from openings in the IVth ventricle, or obstruction to CSF flow within the basal subarachnoid spaces around the fourth ventricle, the ETV will bypass any of these obstructions and relieve the problem if the normal CSF absorptive mechanisms are functioning adequately. Download guidelines on the treatment of hydrocephalus in developing countries.