Dandy-Walker Syndrome

Dandy-Walker Syndrome

Ashley Davidoff MD

The Common Vein Copyright 2010


Dandy-Walker syndrome (DWS), or Dandy-Walker complex, is a congenital malformation of the cerebellum and associated subarachnoid spaces caused by a genetic abnormality and more often affecting females.

Structurally the disorder is centered in the posterior fossa characterized by partial or complete absence of the part vermis and enlargement of the 4th ventricle, and the cisterna magna that may also demonstrate an increase in pressure.  There are three basic types of Dandy Walker deformities DWS malformation, DWS mega cisterna magna and DWS variant.

Functionally the motor system is affected and the patient may present clinically with motor impairment characterized by unsteadiness of gait and lack of muscle coordination.  If there is associated increase in the intracranial pressure then clinical findings may include irritability, and vomiting.  Associated congenital abnormalities include defects of the corpus callosum, cardiac and limb deformities.

The diagnosis may be made prenatally by fetal ultrasound, where enlargement of the CSF spaces around the cerebellum such as cisterna magna and 4th ventricle are characteristic findings.  Fetal karyotyping following amniocentesis may also be helpful.

Treatment is based on anatomic deformities but the most easily correctible is the elevated intracranial pressure which is treated by decompression by placement of a surgically placed shunt.

Normal (a,b,d,e) and Dandy-Walker Syndrome (c,f) associated with

Absence of the Corpus Callosum and Lissencephaly

This T1 weighted MRI is from a normal patient juxtaposed on a T1 weighted MRI from a neonate with agenesis of the corpus callosum, congenital lissencephaly and Dandy Walker syndrome. The normal corpus callosum (purple overlay ) is seen above the ventricles between the ventricles and the supracallosul gyrus and cingulate gyrus. . In the neonate (c,f) the there is no white matter in the expected position of the corpus callosum. These findings are consistent with a diagnosis of agenesis of the corpus callosum In addition, the posterior fossa does not show a normal cerebellum. Instead it is mostly filled with CSF (dark T1 green asterisk) likely due to a dilated 4th ventricle and atrophy of the vermis. Only a small amount of posterior fossa soft tissue is seen. In addition the posterior horns are dilated (blue asterisk). This finding is consistent with a diagnosis of Dandy-Walker syndrome associated with hydrocephalus. Lastly the patient has fewer gyri and sulci than normal. The gyri that are present are also more shallow than normal. These findings are consistent with lissencephaly.

Courtesy James Donnelly MD Copyright 2010 All rights reserved 95466c01L03.8s

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