UNDERSTANDING DANDY-WALKER SYNDROME: THE RARE CONGENITAL BRAIN MALFORMATION
Medically Reviewed by Dr. Sony Sherpa, (MBBS)
Dandy-Walker Syndrome (DWS) is a rare malformation of the brain that affects approximately 1 in every 25,000-35,000 live births.[1] It is characterized by an enlarged fourth ventricle, a cyst in the cerebellum, and a partial or complete absence of the cerebellar vermis.
This article reviews the signs of DWS in children, causes, diagnosis, and treatment options.
What is Dandy-Walker Syndrome?
Dandy-Walker Syndrome, also known as Dandy-Walker malformation, is an inborn anomaly of brain development that concerns the cerebellum and the fourth ventricle in the brain.
The cerebellum is responsible for coordinating movement, while the fourth ventricle is a fluid-filled space next to the cerebellum and brain stem that helps to protect and nourish the brain.[2]
Individuals with DWS have an underdeveloped cerebellum and an enlarged fourth ventricle, leading to a buildup of cerebrospinal fluid (CSF) in the brain. Excess CSF can cause pressure on the brain, especially the brain stem, leading to hydrocephalus.
The key features of DWS are:[3]
- Expansion of the fourth ventricle (a tiny canal permitting fluid movement between the superior and inferior sections of the brain and spinal cord).
- A partial or total lack of the cerebellar vermis (the zone dividing the two hemispheres of the cerebellum).
- A cyst near the internal base of the skull.
- In some instances, there might be an enlargement of the fluid areas around the brain, along with a rise in pressure.
DWS can result in slower growth, vision problems, developmental delays, and chronic symptoms.
What Causes Dandy-Walker Syndrome?
The exact cause of Dandy-Walker Syndrome is not fully understood. Experts believe it results from genetic and environmental factors, with exposure to toxins or infections during pregnancy being highly prevalent.[4] Infants with DWS born without any other genetic conditions have isolated Dandy-Walker Syndrome, a specific type of the condition.
Other causes include genetic disorders, which indicate Syndromic Dandy-Walker Syndrome, another type of DWS. In these cases, syndromic DWS presents as a symptom alongside other birth defects and genetic conditions.[5] Some examples of conditions that occur with Syndromic DWS include:
- Meckel-Gruber syndrome
- Down syndrome
- Walker-Warburg syndrome
Genetic counseling is essential for those with a family history of Dandy-Walker Syndrome (DWS). It provides info on genetics and recurrence risk and aids decision-making for family planning, testing, and prevention. Seek counseling for an accurate assessment and guidance.
Symptoms of Dandy-Walker Syndrome
The Dandy-Walker malformation is detectable at weeks 17-18 during pregnancy. Infants with DWS are born with an enlarged cranium (macrocephaly), the first giveaway sign. Within three months, up to 75% of infants develop hydrocephalus. Up to 10% of infants with DWS do not develop symptoms.
Symptoms in infants vary, yet can include:[6]
- Throwing up
- Irritability or fussiness
- Difficulty feeding
- Slow growth
- Tiredness
- Eyes positioned downward ("sunsetting") or unable to move outward
In older children, signs present as:
- Developmental delays
- Difficulty with coordination and balance
- Muscle stiffness or weakness
- Vision problems, such as double vision
- Convulsions or seizures
Adults with DWS may present with the following:
- Challenges in walking, usually experienced as "stuck" feet
- Gradual cognitive decline and dementia
- Overall reduction in movement speed
- Inability to control the bladder and irregular urination
- Lack of coordination and stability
Dandy-Walker Complex
Dandy-Walker complex is a comprehensive term that covers a range of brain malformations, including Dandy-Walker Syndrome.[7]
Individuals with Dandy-Walker complex may have additional brain abnormalities, such as an enlarged head, a missing corpus callosum (a brain area that connects the two hemispheres), or a malformed brain stem.
Others may not have symptoms or present with milder variations, such as
- Isolated cerebellar vermis hypoplasia, also known as the Dandy-Walker variant, in which the cerebellum is smaller than average.
- Mega-cisterna magna is a condition with head enlargement and a normal cerebellum.
Long-Term Effects and Complications
If left untreated, Dandy-Walker Syndrome can cause serious long-term effects and complications. These may include:
- Intellectual and developmental disabilities: The underdevelopment of the cerebellum can lead to delays in motor skills, speech, and cognitive abilities.
- Vision and hearing problems: The pressure on the brain can also affect the nerves responsible for vision and hearing, leading to related problems.
- Seizures: Individuals with DWS are at a higher risk of developing seizures.
- Behavioral and emotional issues: The challenges of living with DWS can lead to behavioral and emotional issues, such as anxiety and depression.
Diagnosis of Dandy-Walker Syndrome
Dandy-Walker Syndrome is typically diagnosed during pregnancy or shortly after birth.
During pregnancy, an ultrasound may show an enlarged head or a cyst in the cerebellum, which can indicate DWS.
After birth, a physical exam of the infant may reveal an enlarged head or other physical abnormalities.
Imaging tests such as an MRI or CT scan can verify the diagnosis and offer more information on the severity. MRI (magnetic resonance imaging) is a preferable imaging technique for diagnosing DWS, as it provides detailed brain images, swiftly detecting abnormalities in the cerebellum and fourth ventricle.
Doctors may suggest genetic testing to examine your baby's DNA before or after birth to check for other genetic conditions. Tests can include:[8]
Cell-free fetal DNA testing is a diagnostic test using your blood samples to detect fetal DNA. A positive result may indicate issues with the baby's DNA, requiring further testing. A standard result does not guarantee the absence of hidden genetic disorders. Sometimes, additional testing is necessary, including karyotype (simple) or microarray (detailed DNA scan).
Amniocentesis is a medical procedure to collect and screen amniotic fluid for genetic anomalies. It is done in the second trimester and can confirm cell-free fetal DNA test results.
Treatment Options for Dandy-Walker Syndrome
There is currently no cure for Dandy-Walker Syndrome. Available treatment options can manage the symptoms and complications. These may include:
Shunt Surgery
Shunt surgery is the most common treatment for Dandy-Walker Syndrome. It involves placing a thin tube, called a Ventriculoperitoneal shunt, in the brain to drain excess CSF and relieve pressure on the brain. The shunt is usually placed in the fourth ventricle, connecting to another body part, such as the abdomen, facilitating fluid absorption.
While shunt surgery can be effective in managing hydrocephalus, it does come with risks, such as:[9]
- Cerebral hemorrhage or blood clot
- Brain edema
- CSF fluid escape beneath the skin
- Infection in the brain, shunt, or abdomen
- Injury to cerebral tissue
- Seizure episodes
- Intestinal perforation, which can potentially take place post-surgery
Endoscopic Third Ventriculostomy
Endoscopic third ventriculostomy (ETV) is a minimally invasive surgical procedure used to treat hydrocephalus, including cases associated with Dandy-Walker Syndrome (DWS).
It involves creating an opening at the base of the third ventricle with an endoscope, allowing cerebrospinal fluid (CSF) to bypass any blockages and alleviate pressure. ETV provides an alternative route for CSF to flow, reducing the need for a shunt.[10]
The suitability and success of ETV depend on individual factors that a skilled neurosurgeon can evaluate.
Medications
Medications can assist with managing symptoms such as seizures, muscle stiffness, and behavioral issues. These may include anticonvulsants, muscle relaxants, and antidepressants.
Physical and Occupational Therapy
Individuals with DWS can improve their motor skills, coordination, and balance with the help of physical and occupational therapy. These therapies can also help with speech and cognitive delays.[11]
Follow-Up Appointments and Care
It is critical for individuals with DWS to have regular check-ups with their healthcare providers to observe their condition, keep track of their progress, and address any issues that may arise.
If the infant has had shunt surgery, caregivers need to take heed of specific instructions on how to look after them. It is crucial for families to educate themselves about the condition and connect with support groups and resources for additional support.
Living with Dandy-Walker Syndrome
Living with Dandy-Walker Syndrome can be challenging for the affected individuals and those concerned. However, individuals with DWS can lead fulfilling lives with the right support and management.
The life expectancy and prognosis for individuals with Dandy-Walker Syndrome can vary depending on the presence of other health issues and their collective severity. In some cases, individuals with DWS may have a normal life expectancy, while others may have a shorter life expectancy due to complications.
Early detection and intervention can offer an improved prognosis to individuals with DWS. With proper management, many individuals can lead fulfilling lives.
Latest Breakthroughs in DWS Research
Research into Dandy-Walker Syndrome is ongoing. There is no confirmed cause, which makes developing an optimal single treatment difficult. Studies continue to shed light on potential genetic causes of DWS, which can lead to new treatment options in the future.
Additionally, advancements in imaging technology, such as 3D MRI, have allowed for more accurate and detailed diagnosis of DWS, leading to better treatment and management options.
Conclusion
Dandy-Walker Syndrome, a rare congenital brain malformation, can have serious long-term effects if left untreated. Early detection and treatment can greatly enhance the prognosis for individuals with DWS, and with proper management, many individuals can lead fulfilling lives. Ongoing research and technological advancements provide hope for a better understanding of this complex condition.
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