2. DANDY-WALKER MALFORMATION
Dandy-Walker Malformation is a congenital brain
abnormality that primarily affects the development of the
cerebellum and the fluid-filled spaces (ventricles) around
it. It is characterized by a range of structural abnormalities
in the posterior fossa of the brain which includes:
Hypoplasia or agenesis of cerebellar vermis
Cystic dilatation of fourth ventricle
Enlargement of posterior cranial fossa
3. CONCEPTS RELATED TO
DANDY-WALKER MALFORMATION
Congenital Condition: Dandy-Walker Malformation is present at
birth and arises during fetal development. It is considered a congenital
condition.
Cerebellar Abnormalities: The primary feature of Dandy-Walker
Malformation is the underdevelopment or malformation of the
cerebellum, a region at the back of the brain responsible for
coordination, balance, and fine motor skills. This can lead to motor
function problems.
Fourth Ventricle Issues: There is often an enlargement of the fourth
ventricle, one of the fluid-filled spaces within the brain. This can
result in the accumulation of cerebrospinal fluid (CSF) in the
ventricles, leading to hydrocephalus.
Communication Issues: In some cases, there may be a cystic
structure within the posterior fossa, which may obstruct the normal
flow of CSF. This can result in a non-communicating type of
hydrocephalus.
4. CAUSES OF DWS
The exact cause of Dandy-Walker Malformation is not fully understood.
It is believed to be due to a combination of genetic and environmental
factors, but it can occur sporadically without a family history. The
condition starts in the first month of pregnancy. As a baby’s brain develops,
the cerebellum does not develop correctly, and fluid begins to build up in the
brain.
Possible causes of Dandy-Walker syndrome includes:
chromosomal defects, which occur in people with:
trisomy 18 (an extra copy of chromosome 18)
trisomy 13
trisomy 21
trisomy 9
Certain viral infections that may pass from the pregnant person to the fetus
gestational diabetes occurs in 2 % of pregnancies
Exposure of the unborn baby to certain toxins or medications
Recessive genes may be responsible for the condition. These genes may
cause cerebellar vermis hypoplasia, which is a small or underdeveloped
cerebellum, and mega-cisterna manga, which is a large cerebrospinal space.
5. TYPES OF DWS
Types: There are different types of Dandy-Walker
Malformation, including:
Classic Dandy-Walker Malformation: Characterized
by the presence of a cystic structure in the posterior
fossa.
Non-Communicating Dandy-Walker Variant:
Involves obstruction of CSF flow.
Mega Cisterna Magna: A milder form with an enlarged
cisterna magna, which is not considered a true Dandy-
Walker Malformation, but it shares some features.
6. CLINICAL FEATURES OF DWS
There is often an enlargement of the fourth ventricle, one
of the fluid-filled spaces within the brain. This can result in
the accumulation of cerebrospinal fluid (CSF) in the
ventricles, leading to hydrocephalus.
Absence of foramen of Luschka and Magendie
Dilatation of fourth ventricle
Obstruction of cerebral aqueduct
Thinning of occipial bone
Brainstem compression
Elevation of sinus above Lamdoid suture
Elevation of straight sinus and tentorium cerebelli
7. DIAGNOSIS OF DWS
Diagnosis: Dandy-Walker Malformation is typically diagnosed through imaging
studies, such as MRI or ultrasound, which reveal the structural abnormalities in the
brain.
MRI (Magnetic Resonance Imaging): MRI images are commonly used to diagnose
and assess Dandy-Walker Syndrome/Malformation. They can show the following
features:
Enlarged posterior fossa: The cerebellum may be smaller and pushed towards the
back of the skull.
Cyst or fluid-filled space: A characteristic cyst or fluid-filled sac in the posterior
fossa, which is a hallmark of Dandy-Walker Malformation.
Dilated fourth ventricle: Enlargement of the fourth ventricle, which is often part of
the condition.
Hydrocephalus: An accumulation of cerebrospinal fluid (CSF) in the brain's
ventricles due to the obstruction of CSF flow.
Ultrasound: In fetal medicine, ultrasound images can also show signs of Dandy-
Walker Syndrome/Malformation. These images may reveal an enlarged posterior fossa
and cystic structures in the fetal brain.
CT (Computed Tomography): CT scans may be used in some cases to visualize the
structural abnormalities associated with Dandy-Walker Malformation. However, MRI
is generally preferred due to its superior soft tissue contrast.
8. TREATMENT
Symptoms: The symptoms of Dandy-Walker Malformation can vary
widely among individuals but may include developmental delays,
problems with coordination and balance, muscle weakness,
intellectual disabilities, and visual or hearing impairments.
Hydrocephalus-related symptoms, such as headaches and vomiting,
can also occur.
Treatment: Management of Dandy-Walker Malformation depends
on the severity of symptoms and associated conditions. Treatment
may involve surgical interventions to address hydrocephalus,
physical and occupational therapy to manage symptoms, and
ongoing monitoring by healthcare professionals.
Prognosis: The prognosis for individuals with Dandy-Walker
Malformation varies widely. Some individuals may lead relatively
normal lives with appropriate interventions and support, while others
may experience significant challenges due to the severity of their
condition.
