The Brave and Beautiful Faces of those living with Hydrocephalus

 Understanding Hydrocephalus

Hydrocephalus comes from the Greek words hydro meaning water and cephalus meaning head.

Hydrocephalus is a condition in which too much cerebrospinal fluid (CSF), a clear liquid that surrounds both the spinal cord and the brain builds up and collects in cavities of the brain called ventricles. Hydrocephalus occurs when there is an imbalance between the amount of CSF that is produced and the rate at which it is absorbed. As the CSF builds up, it causes the ventricles to enlarge and the pressure inside the head to increase. Pressure and swelling on the brain will lead to, in some cases severe brain damage, vision impairment, or death. 

• Over one million people in the United States currently live with hydrocephalus. Many more in other countries.
For every 500 babies born in this country, one will have hydrocephalus.
• Hydrocephalus is the most common reason for brain surgery in children.
• It is estimated that more than 700,000 Americans have NPH, but less than 20% receive an appropriate diagnosis. 

For hydrocephalus to develop, one of three factors must disturb the normal flow of CSF:

1. The brain produces too much CSF. (Rare)

2. Outflow from the ventricles is blocked, a condition called obstructive hydrocephalus. (More commonly)

3. The bloodstream is unable to reabsorb CSF, leading to an excess of fluid, referred to as communicating hydrocephalus.

Who develops hydrocephalus?

Hydrocephalus affects infants to elderly.

Infants: Hydrocephalus may develop in the womb or after birth as a result of a congenital defect. This defect is not necessarily hereditary. Hydrocephalus may also result from complications associated with premature birth, or infection.Hydrocephalus that occurs pre-birth or at birth is called "congenital hydrocephalus."Congenital hydrocephalus is now often diagnosed before birth through routine ultrasound.

Children, young and middle-aged adults: Hydrocephalus may develop during these years as a result of intracranial bleeding, stroke, brain injury, tumor growth, meningitis or other factors. Hydrocephalus that occurs after birth as a result of one of these factors is called “acquired hydrocephalus.”

 

Older Adults/Seniors: When it is diagnosed later in life, age 55 and older, hydrocephalus is typically called “adult onset hydrocephalus.” It is diagnosed when the ventricles of the brain are enlarged, but there is little or no increase in the pressure within the ventricles. Sometimes the cause of "normal pressure hydrocephalus" (NPH) is known – but most often it is idiopathic, which means the cause is not known.

Communicating Versus Non-Communicating Hydrocephalus:

• Communicating hydrocephalus occurs when the flow of cerebrospinal fluid (CSF) is blocked after it exits the ventricles. This form is called communicating, because the CSF can still flow between the ventricles, which remain open.

• Non-communicating hydrocephalus -- also called "obstructive" hydrocephalus -- occurs when the flow of CSF is blocked along one or more of the narrow pathways connecting the ventricles. One of the most common causes of hydrocephalus is "aqueductal stenosis." In this case, hydrocephalus results from a narrowing of the aqueduct of Sylvius, a small passageway between the third and fourth ventricles in the middle of the brain.

Common Causes of Congenital Hydrocephalus

Aqueductal stenosis – The most common cause of congenital hydrocephalus is an obstruction called aqueductal stenosis. This occurs when the long, narrow passageway between the third and fourth ventricles (the aqueduct of Sylvius) is narrowed or blocked, perhaps because of infection, hemorrhage, or a tumor. Fluid accumulates “upstream” from the obstruction, producing hydrocephalus.

Neural tube defect – Another common cause of hydrocephalus is a neural tube defect (NTD). An open NTD, where the spinal cord is exposed at birth and is often leaking CSF, is called a myelomeningocele, and is often referred to as spina bifida. This kind of NTD usually leads to the Chiari II malformation, which causes part of the cerebellum and the fourth ventricle to push downward through the opening at the base of the skull into the spinal cord area, blocking CSF flow out of the fourth ventricle and causing hydrocephalus. Please see the National Institute of Neurological Disorders and Stroke (NINDS) for more information on neural tube defects.

Arachnoid cysts – Congenital hydrocephalus can also be caused by arachnoid cysts, which may occur anywhere in the brain. In children, they’re often located at the back of the brain (posterior fossa) and in the area of the third ventricle. These cysts are filled with CSF and lined with the arachnoid membrane, one of the three meningeal coverings. Some arachnoid cysts are self-contained, while others are connected with the ventricles or the subarachnoid space. The fluid trapped by the cysts may block the CSF pathways, causing hydrocephalus.

Dandy-Walker syndrome – In Dandy-Walker syndrome, another cause of congenital hydrocephalus, the fourth ventricle becomes enlarged because its outlets are partly or completely closed and part of the cerebellum fails to develop. Dandy-Walker syndrome may also be associated with abnormal development in other parts of the brain and sometimes leads to aqueductal stenosis. In some instances, two shunts are placed in the child’s ventricles — one in the lateral ventricle and another in the fourth ventricle to manage the hydrocephalus. Please see the National Institute of Neurological Disorders and Stroke (NINDS) for more information on Dandy-Walker syndrome.

Chiari malformation – There are two types of Chiari malformation. Both types occur in the bottom of the brain stem where the brain and spinal cord join. The lowest portion of the brain is displaced and is lower than normal pushing down into the spinal column. Please see the National Institute of Neurological Disorders and Stroke (NINDS) for more information on Chiari malformation.

Common Causes of Acquired Hydrocephalus

Intraventricular hemorrhage – An intraventricular hemorrhage, which most frequently affects premature newborns, may cause an acquired form of hydrocephalus. When small blood vessels alongside the ventricular lining rupture, blood may block or scar the ventricles or plug the arachnoid villi, which allow CSF to be absorbed. When the CSF can’t be absorbed, hydrocephalus results.

Meningitis – Meningitis is an inflammation of the membranes of the brain and spinal cord. Caused by a bacterial or (less frequently) viral infection, meningitis can scar the delicate membranes called meninges that line the CSF pathway. An acquired form of hydrocephalus may develop if this scarring obstructs the flow of CSF as it passes through the narrow ventricles or over the surfaces of the brain in the subarachnoid space.

Head injury – A head injury can damage the brain’s tissues, nerves, or blood vessels. Blood from ruptured vessels may enter the CSF pathway, causing inflammation. Sites of CSF absorption might then be blocked by scarred membranes – meninges – or by blood cells. The CSF flow is restricted, and hydrocephalus develops.

Brain tumors – In children, brain tumors most commonly occur in the back of the brain which is referred to as the posterior fossa. As a tumor grows, it may fill or compress the fourth ventricle, blocking the flow of CSF and causing hydrocephalus. A tumor somewhere else in the brain might also block or compress the ventricular system. Please see the National Institute of Neurological Disorders and Stroke (NINDS) for more information on brain tumors.

Symptoms of Hydrocephalus

The symptoms of untreated hydrocephalus vary. During pregnancy, routine ultrasound can detect enlarged ventricles or spaces within a baby’s brain. In an infant, the most obvious sign of hydrocephalus is an abnormal enlargement of the baby’s head. In children symptoms tend to be related to high pressure and may include nausea, vomiting, headache and vision problems.

In young and middle aged adults symptoms most often include dizziness and vision problems. In older adults with normal pressure hydrocephalus (NPH) the symptoms are more likely to be loss of function in three main areas: walking, thinking and bladder control.

Infants and Children
•Abnormal head enlargement
•Tense, bulging fontanel
•Prominent scalp veins
•Skull bones may feel separated
•Vomiting, sleepiness, irritability
•Headache, nausea, vomiting, vision
•Downward deviation of eyes

Young and Middle Aged Adults
•Chronic headaches
•Difficulty walking/gait disturbances
•Cognitive challenges or complaints
•Urinary urgency or incontinence

Older Adults (NPH)
•Difficulty walking/gait disturbances
•Cognitive challenges/mild dementia
•Urinary urgency or incontinence

Diagnosing Hydrocephalus

The most common initial diagnostic test to determine hydrocephalus at any age is an image of the brain using CT or MRI to identify if the ventricles or spaces within the brain are enlarged. More tests are often performed in adults in order to diagnosis the condition. The decision to order a particular test may depend on the specific clinical situation, as well as the preference and experience of the medical team. Not all of the tests described here are required in order to make a diagnosis.


•Clinical exams to evaluate symptoms consist of an interview and/or physical neurological examination.
•Brain images to detect enlarged ventricles include magnetic resonance imaging (MRI) and computerized tomography (CT).
•CSF tests to predict shunt responsiveness and/or determine shunt pressure include lumbar puncture, external lumbar drainage, measurement of CSF outflow resistance, intracranial pressure (ICP) monitoring and isotopic cisternography.

Can Hydrocephalus Be Cured?

There is no cure for hydrocephalus at this time. In most cases, it is a condition that is present for life. Research is vital to understanding the complex condition of how and why CSF builds up causing hydrocephalus. There is always hope.

Treatment Options

There is currently no known way to prevent or cure hydrocephalus and the only treatment option today requires brain surgery. With early detection and appropriate intervention of hydrocephalus, the future for many is promising. Recent research is advancing knowledge and moving us closer to a cure. Advances in technology as well as diagnostic and treatment protocols are helping more and more people with hydrocephalus to lead full and active lives.

There are three forms of surgical treatment currently used to manage hydrocephalus 

The most common treatment for hydrocephalus—and the most common procedure performed by pediatric neurosurgeons in the United States—is the surgical implantation of a device called a shunt.

A shunt is a flexible tube placed into the ventricular system of the brain which diverts the flow of CSF into another region of the body, most often the abdominal cavity, where it can be absorbed. A valve within the shunt maintains CSF at normal pressure within the ventricles.

Common Shunts And Placement Locations

• Ventriculo-peritoneal - VP  (Location) Ventricle to Peritoneal cavity
• Ventriculo-atrial - VA  (Location) Ventricle to Right atrium of the heart
• Ventriculo-pleural - VPL (Location) Ventricle to Pleural lung cavity
• Lumbo-peritoneal - LP (Location) Lumbar spine to Peritoneal cavity

CSF shunts are commonly used to treat hydrocephalus. If left unchecked, the CSF imbalance can lead to elevated intracranial pressure (ICP) which can lead to a variety of complications. CSF shunts can be used to alleviate these problems in patients who suffer from hydrocephalus. Shunts can come in a variety of forms but all of them consist of an inflow catheter communicating with an outflow catheter under the control of a valve which regulates pressure (differential pressure valves) or controls flow (flow-regulated valves).

The main differences between shunts are usually in:
•the materials used to construct them,
•the types of valves mechanism used,
•the source of CSF (ventricular, lumbar, etc.) and location of the drainage end-point (peritoneal, atrial, pleural, etc.), and
•whether or not the valve is externally adjustable.

Routine treatment complications are infection, obstruction, and overdrainage to name a few. Although some (regrettably, the minority) of the patients with shunts can go for years without complications, even those lucky few are potentially one shunt malfunction away from a major crisis. At any time, and without warning, a shunt complication can require emergency intervention.

Complications of Shunt Systems

Hydrocephalus can be treated with a shunt system, and this treatment often includes complications. An estimated 50% of shunts in the pediatric population fail within two years of placement and repeated neurosurgical operations are often required.

The most common shunt complications are malfunction and infection.Shunt malfunction is a partial or complete blockage of the shunt that causes it to function intermittently or not at all. When a blockage occurs, CSF accumulates and can result in symptoms of untreated hydrocephalus.

A shunt blockage from blood cells, tissue or bacteria can occur in any part of the shunt. Both the ventricular catheter – the portion of the tubing placed in the brain – and the distal part of the catheter – the tubing that drains fluid to another part of the body – can become blocked by tissue from the choroid plexus or ventricles. The distal part of the catheter is more often blocked in adults.

Shunts are very durable, but their components can become disengaged or fractured as a result of wear or as a child grows, and occasionally they dislodge from where they were originally placed. More rarely, a valve will fail because of a mechanical malfunction.

Shunt Infection

Shunt infection is usually caused by a person’s own bacterial organisms and isn’t acquired from other children or adults who are ill. The most common infection is Staphylococcus Epidermidis, which is normally found on the surface of a person’s skin and in the sweat glands and hair follicles deep within the skin. This type of infection is most likely seen one to three months after surgery, but can occur up to six months after the placement of a shunt. People with ventriculoperitoneal (VP) shunts are at risk of developing a shunt infection secondary to abdominal infection. Those patients treated with ventriculoatrial (VA) shunts may develop generalized infection, which can quickly become serious.

Signs & Symptoms of Shunt Infection

Shunt infection frequently results in fever and may happen with or without a shunt obstruction. Sometimes shunt infection also produces reddening or swelling along the shunt tract.  If an infection is suspected it is critical to notify the neurosurgeon immediately or go to the emergency room.  A shunt infection must be treated immediately to avoid life-threatening illness or possible brain damage.

Other Shunt Complications

Over drainage causes the ventricles to decrease in size creating slit-like ventricles as a result of the brain and its meninges pulling away from the skull. Slit-like ventricles, sometimes called slit-ventricle syndrome (SVS), are most commonly a problem in young adults who have been shunted since childhood. A particular symptom of SVS is severe intermittent headaches that are often relieved when lying down. Imaging studies are required to determine SVS, which is typically indicated by smaller than normal ventricles. Most shunt manufacturers have shunt hardware designed to address slit-ventricle syndrome.

Under drainage causes the ventricles to increase in size and can fail to relieve the symptoms of hydrocephalus. To restore a balanced flow of CSF it may be necessary to place a new shunt with a more accurate pressure valve. For those who have externally adjustable or programmable valves, the balance of flow can be restored by re-setting the opening pressure.

Subdural hematoma occurs if blood from broken vessels in the meninges becomes trapped between the brain and skull. This is most common in older adults with normal pressure hydrocephalus (NPH) and requires surgery to correct.

Multiloculated hydrocephalus is a located (isolated) CSF compartment in the ventricular system that is enlarged and not in communication with the normal ventricle. It may be caused by birth trauma, neonatal intraventricular hemorrhage, ventriculitis, shunt related infection, over drainage or other conditions. This complication may be difficult to identify because it is typically seen in infants and children who may be neurologically compromised. Surgical treatments include multiple shunt placement, ventricular catheters with multiple perforations or openings, craniotomy and fenestration (opening) of the intraventricular loculations.

Seizures sometimes occur in people with hydrocephalus. There is no correlation between the number of shunt revisions or the site of shunt placement and an increased risk of developing seizures. Past studies have shown that children with hydrocephalus who have been treated with a shunt and who also have significant cognitive delay or motor disability are more likely to experience seizures than those without cognitive or motor delays. Studies have also indicated that seizures are not likely to occur at the time of shunt malfunction, and that the most likely explanation of seizure disorder is the presence of associated malformations of the cerebral cortex.

Abdominal complications can occur in people with hydrocephalus treated with a shunt. The peritoneum or abdominal area is the most popular site for distal catheter implantation. Although ventriculoperitoneal (VP) shunts do not have fewer complications than ventriculoatrial shunts, the complications are less severe and have a lower mortality rate. Shunt complications that develop in the peritoneum or abdominal area include peritoneal pseudocysts, lost distal catheters, bowel perforations and hernias.

A second treatment option for hydrocephalus is a surgical procedure called endoscopic third ventriculostomy (ETV). For a limited number of patients, hydrocephalus treatment can be performed using an alternative procedure called third ventriculostomy. In this hydrocephalus treatment, a neuroendoscope - a small camera designed to visualize small and difficult-to-reach surgical areas -- allows a doctor to view the ventricular surface using fiber optic technology. The scope is guided into position so that a small hole can be made in the floor of the third ventricle, allowing the CSF to bypass the obstruction and flow toward the site of resorption around the surface of the brain.  This approach is an important alternative to shunting for obstructive hydrocephalus and may be useful in other cases as well.

The third treatment option involves the addition of choroid plexus cauterization with endoscopic third ventriculostomy in infants. The neurosurgeon uses a device to burn or cauterize tissue from the choroid plexus. The choroid plexus is a network of vessels in the ventricles of the brain where cerebrospinal fluid is produced.

The success rate for ETV or ETV/CPC depends upon patient factors such as age, cause of hydrocephalus, and whether there is scarring in the fluid space below the floor of the third ventricle. For some patients, the chance for success of the ETV may be up to 90%; however, for others, ETV – with the addition of CPC for infants – may not be recommended because the chances for success are sufficiently low. Your neurosurgeon should be able to provide you with a reliable estimate of the likelihood for success in your particular situation prior to the operation. It’s critical that parents and patients understand that ETV is not always a permanent cure for hydrocephalus. Candid communication with your physician regarding the definition of success is important when considering ETV. 

An estimated 50% of shunts fail within two years and 20-50% of ETVs close up within five years. Either treatment can fail at any time. Be informed and vigilant. Be prepared to act quickly. Mere hours can mean the difference between a resolvable complication and brain damage or even death, especially in children.