Dandy Walker Syndrome: Signs, Symptoms, & Treatment

The cerebellum and other some other important lower brain structures rest in an indented area of bone in

the lower, back part of the skull known as the posterior cranial fossa. The posterior cranial fossa becomes

larger in patients with Dandy Walker syndrome. In addition, people with Dandy Walker syndrome can

develop cysts can in the posterior cranial fossa.

WHAT ARE SOME OTHER BRAIN ABNORMALITIES PRESENT IN DANDY WALKER SYNDROME?

In addition to the abnormalities mentioned in the previous section, there are other brain abnormalities that

are sometimes present in Dandy Walker syndrome. In some individuals, the cyst that forms in the fourth

ventricle (see above) closes two normal openings in that ventricle. These two openings are known as the

foramen of Luschka and the foramen of Magendie. As a result, the cerebrospinal fluid that is in the fourth

ventricle cannot escape out of those openings and the fluid builds up, causing hydrocephalus.

Hydrocephalus is a condition in which there is an abnormal increase in cerebrospinal fluid inside the head.

Another characteristic is the partial or total absence of the corpus callosum, which is a large band of

nerve fibers in the brain that help the two sides of the brain communicate with each other. A partial

absence of the corpus callosum is common in Dandy Walker Syndrome. Heterotopia can be present as

well. Heterotopia refers to when gray matter (a gray appearing substance) in the brain is out of its normal

place and has typically made its way into the white matter (a white appearing substance) of the cerebrum,

where it should not be. The cerebrum is the top section of the brain.

Other brain abnormalities include an absence of gyri (rounded elevations) or abnormally small gyri. Gyri

are normally present on the brain and help increase its surface area (the total area exposed on the

surface).

WHAT ARE THE SIGNS AND SYMPTOMS OF DANDY WALKER SYNDROME?

It is important to note that the signs and symptoms of Dandy Walker Syndrome can occur suddenly or

never occur at all. In fact, sometimes Dandy Walker syndrome is not diagnosed until the person reaches

adulthood, although most people are diagnosed by age one. The following is a list of some signs and

symptoms that can occur in Dandy Walker syndrome. The list is variable and does not occur in all people

affected with this condition.

Most of the signs and symptoms of Dandy Walker syndrome are due to a buildup of cerebrospinal fluid in

the head, a condition known as hydrocephalus. Hydrocephalus is usually accompanied by increased

pressure within the bones that surround the brain. This pressure can also cause the sutures (places

where two bones join together) of the skull to separate, resulting in an abnormally large skull. Sometimes

this is the only sign of Dandy Walker syndrome, and it can happen rapidly. The "soft spot" in infants, which

is the area where the skull bones have not yet closed together, can bulge outwards.

People with hydrocephalus have a thin scalp (the skin that covers the skull). As a result, the veins in the

scalp are easily seen in people with hydrocephalus. Also, as was mentioned earlier, infants sometimes

have a difficult time moving their head if they have an abnormal buildup of fluid in it. They may also have a

poor control of their neck muscles. Some people with Dandy Walker syndrome experience titubation,

which is an unsteady posture characterized by staggering or stumbling while walking and swaying of the

head and upper part of the body while sitting.

Because of the incomplete development of the cerebellum, which is important for controlling motor

abilities, infants with Dandy Walker syndrome tend to display poor motor development. For example, many

children with Dandy Walker syndrome have a very difficult time walking. Many people with Dandy Walker

syndrome also have spasticity. Spasticity is a condition in which there is increased tension in muscles

that resist the force of gravity (the natural force that pulls objects downwards) and increased resistance to

stretch.

In older children with Dandy Walker Syndrome, increased pressure in the head can cause irritability,

vomiting, and convulsions (abnormal, severe, involuntary muscle movements). Approximately 20 to 30%

of children with Dandy Walker syndrome experience seizures, which are involuntary muscle movements

and/or decreased awareness of the environment due to overexcitement of nerve cells in the brain.

Incomplete development of the cerebellum in older children with Dandy Walker syndrome can cause

impaired motor coordination, imbalance, dizziness, and uncontrollable jerky eye movements.

Some other problems with the eyes that can occur in people with Dandy Walker syndrome include

catracts, retinal dysgenesis, and choroid coloboma. Cataracts is a darkening of the lens in the eye(s).

The lens is an organ located between the colored part of the eye, that bends light as it enters the eye.

Retinal dysgenesis is an abnormal formation of the retina that occurs when the baby is developing inside

of the mother. The retina is an area at the back of the eye that is sensitive to light. Choroid coloboma is a

birth defect in which the choroid of the eye is not formed properly. Choroid is a layer in the eye between

the sclera (the outer, white part of the eye) and the retina. All of these abnormalities of the eye make it

difficult to see.

Some people with Dandy Walker syndrome have sleep apnea, which is a disorder in which the person

does not breath for periods of time while sleeping. Other signs and symptoms of Dandy Walker syndrome

include increased head size, a bulge in the back of the head, abnormal breathing, and poor functioning of

the cranial nerves. Cranial nerves are nerves that emerge from the brain. Approximately 30% of children

with Dandy Walker syndrome have abnormal formations of the face, heart, fingers, face, arms, and/or

legs. One type of abnormality is the hands and feet is the presence of more than the normal number of

fingers or toes. In some cases, two are more fingers are joined together.

One type of facial abnormality is cleft lip. In cleft lip, the upper lip has not formed properly and there are

one or more openings in it. Cleft palate, which is an incomplete formation of the roof of the mouth, is also

seen in some cases of Dandy walker syndrome. The incomplete formation in cleft palate is characterized

by a groove in the middle of the roof of the mouth.

Some people with Dandy Walker have abnormalities in the structure of the urinary tract. The urinary tract

is the part of the body that deals with the formation and excretion of urine (pee). To excrete means to

release from the body as waste. An example of such an abnormality would be polycystic kidney, a

condition in which the kidneys are too large and contain many cysts on them. The kidneys are two organs

located on each side of the spine, behind the stomach. The kidneys filter (remove) wastes from the blood.

IS THE SPINE EVER AFFECTED IN DANDY WALKER SYNDROME?

Yes, but not always. Sometimes, the cyst along the fourth ventricle (see previous sections) extends into

the opening where the spinal cord is located. A condition that affects the spinal cord, which is associated

with Dandy Walker syndrome is syringomyelia. Syringomyelia is a condition in which long, fluid filled

spaces are present in the central gray matter (a gray looking substance) of the spinal cord and

surrounded by thick tissues made of glial cells. Glial cells are supportive cells. The long, fluid filled spaces

look like tubes in the spinal cord. It can also look like one big tube in the spinal cord.

The vertebrae in the lower part of the spine can be abnormal in people with Dandy Walker syndrome.

Vertebrae are bones that form an opening in which the spinal cord passes.

WHAT IS THE INTELLIGENCE LEVEL OF PEOPLE WITH DANDY WALKER SYNDROME?

Unfortunately, many children with Dandy Walker syndrome suffer from mental retardation. However, 50%

of children with Dandy Walker syndrome have normal cognitive functioning.

WHAT CAUSES DANDY WALKER SYNDROME?

In most cases, the cause of Dandy Walker syndrome is unknown. It has been suggested that

abnormalities in chromosomes may cause some cases of Dandy Walker syndrome. Chromosomes are

structures in a person's cells that contain genes. Genes are units of material that contain coded

instructions as for how certain bodily characteristics (such as eye color) will develop. All of a person's

genes come from his/her parents. Some genes are normal whereas others may be abnormal. Abnormal

genes can cause diseases.

It has also been suggested that Dandy Walker syndrome can be caused by exposure to an anti-acne

(anti-pimple) medication called isotretinoin during the first three months that the baby is developing inside

the mother.

HOW IS DANDY WALKER SYNDROME DIAGNOSED?

Dandy Walker syndrome is diagnosed with X-rays and a CT (computerized tomography) scan of the brain.

CT scanning is a more advanced imaging technique that uses x-rays and computer technology to

produces more clear and detailed pictures than a traditional x-ray. Magnetic resonance imaging (MRI)

scans of the brain can also be used. MRI scans produce extremely detailed pictures of the inside of the

body by using very powerful magnets and computer technology. MRI scans are more detailed and more

expensive that CT scans. A rarely used technique to diagnose Dandy Walker syndrome is a

ventriculogram. A ventriculogram is a specific x-ray study of the ventricles in the brain. Ventricles are

openings in the brain that produce the cushiony fluid that protects the brain and spine.

WHAT IS THE AGE OF MOST PEOPLE WHEN DIAGNOSED WITH DANDY WALKER SYNDROME?

Approximately 80% of children that are diagnosed with Dandy Walker syndrome receive this diagnosis by

age 1. The diagnosis is usually made this early because of the enlarged head caused by the buildup of

cerebrospinal fluid. This buildup of fluid often makes it difficult for the infant to control his/her head, which

usually leads parents to bring the child in to the doctor for an evaluation.

HOW IS DANDY WALKER SYNDROME TREATED?

Unfortunately, as of yet, there is no way to reverse the main structural abnormalities caused by Dandy

Walker syndrome. However, some of the other abnormalities associated with this condition can be

treated. For example, physical therapy is often used to help patients improve their abnormal motor

functioning. However, many individuals will still continue to have difficulty walking and have poor balance.

Another treatment is to give medication to reduce seizures. Seizures are involuntary muscle movements

and/or decreased awareness of the environment due to overexcitement of nerve cells in the brain.

To treat the buildup of fluid in the head, a flexible tube called a shunt can be placed in the ventricles of the

brain, the inside of the brain, or the posterior fossa (the indented bone in the lower, back part of the skull).

From one of these areas, the tube will drain the extra fluid into the space between layers that line the

belly. The fluid will then be absorbed along the wall of the belly.

The shunting procedure will decrease the pressure in the head and will thus prevent the head from

widening further. Sometimes, more than one tube needs to be placed, such as a tube in a ventricle and a

tube in the posterior fossa. If these two spaces are not connecting, the surgeon will connect the tubes to

a common valve that drains the fluid.

WHY CAN'T THE CYST BE REMOVED?

The cyst cannot be removed with surgery because it already has blood vessels that go through it and

connect to the brain. Taking out the cysts would thus cause too much damage to the brain.

HOW MANY CHILDREN ARE BORN WITH DANDY WALKER SYNDROME?

Dandy Walker Syndrome is rare, occurring in about 1 out of every 25,000 to 30,000 births.

IS DANDY WALKER SYNDROME SEEN MORE IN MALES OR FEMALES?

Although some studies report that approximately equal numbers of males and females are affected with

Dandy Walker Syndrome, others report that more females are affected than males.

WHAT IS THE PROGNOSIS OF PEOPLE WITH DANDY WALKER SYNDROME?

The prognosis of people with Dandy Walker syndrome is variable, even when the buildup of fluid in the

head is correctly treated at an early stage. Generally, the more severe the defects, the worse intellectual

abilities and the less likely the chance of survival will be.

WHAT ELSE IS DANDY WALKER SYNDROME KNOWN AS?

Dandy Walker syndrome is also known as Dandy Walker, Dandy Walker cyst, Dandy Walker variant, and

Dandy Walker malformation.

WHAT IS THE ORIGIN OF THE TERM, DANDY WALKER SYNDROME?

Dandy Walker syndrome was named after two physicians, Walter E. Dandy and Arthur E. Walker. Walker

was an American surgeon who lived from 1907 to 1995. Dandy was an American neurosurgeon who lived

from 1886 to 1946. Neurosurgeons operate on the brain, spine, and/or nerves outside the brain and

spine.

It is interesting to note, however, that the condition was fist described by Dandy and a U.S. physician

named Kenneth Blackfan in 1914. Blackfan lived from 1883 to 1941. Dandy and Blackfan described the

case of a 13-year-old child with an abnormally high amount of cerebrospinal fluid in the head, cysts in the

back of the skull, and an incompletely developed vermis of the cerebellum. Please see the beginning of

this entry for a description of these terms.

Many years went by and it 1942, Arthur Walker and his colleague, Johhn Taggart, gave a talk in which

they described nine cases (including the one described by Walker and Blackfan) in which children were

born with the similar signs mentioned above. The term, "Dandy-Walker syndrome" was first used in 1954

by C. E. Benda in a paper he published entitled, "The Dandy-Walker syndrome or the so-called atresia of

the foramen of Magendie." The article was published in the Journal of Neuropathology and Experimental

Neurology, Volume 13, pages 14-39.