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Dandy-Walker syndrome

Background

Dandy-Walker syndrome (DWS) is a brain malformation involving the cerebellum (an area at the back of the brain that controls movement) and the fluid-filled spaces around it. Within the brain, there is a fluid called cerebrospinal fluid (CSF), which cushions the brain and spine. Ventricles are spaces either side of the brain and allow the CSF to flow around the brain, spine and nervous system. There are 'so-called variants' but the main features of DWS include:

  • an enlargement of the fourth ventricle (a small channel that allows fluid to flow freely between the upper and lower areas of the brain and spinal cord)
  • a partial or complete absence of the cerebellar vermis (area of the brain between the two cerebellar hemispheres)
  • cyst formation (a cyst is a closed sac filled with solids, fluids or semi-solids) near the internal base of the skull.

Credits

Medical text written November 2002 by Mr N Buxton. Last updated February 2013 by Mr N Buxton, Consultant Paediatric Neurosurgeon, Alder Hey Children's Hospital, Liverpool, UK.

Although great care has been taken in the compilation and preparation of all entries to ensure accuracy, we cannot accept responsibility for any errors or omissions. Any medical information is provided is for education/information purposes and is not designed to replace medical advice by a qualified medical professional.

This entry is pending review, and certain details may no longer be up to date. Please ring our helpline or email our Rare Conditions Information Officer for more information.

What are the symptoms?

Excessive production of CSF, or failure of CSF reabsorption due to obstruction of the passageways out of the fourth ventricle, leads to an accumulation of fluid in the brain ventricles. This can cause raised intracranial pressure (ICP). Hydrocephalus is present in approximately 90 per cent of people affected by DWS. And can result in the failure of parts of the cerebellum to develop correctly. A large cyst is then visible on scans of the back of the brain.

Symptoms caused by ICP can include:

In early infancy:

  • slow motor development
  • progressive enlargement of the skull.

In older children:

  • irritability
  • vomiting
  • convulsions
  • signs of cerebellar dysfunction, such as unsteadiness, lack of muscle coordination or jerky movements of the eyes
  • increased head circumference
  • bulging at the back of the skull
  • problems with the nerves that control the eyes, face and neck
  • abnormal breathing
  • seizures.

What are the causes?

In the majority of cases of DWS the cause is not known. The syndrome is most often congenital (present at birth), but it can be acquired due to infection, chemical agents and other pre-birth factors. In some families, a genetic basis has been identified.

How is it diagnosed?

DWS is generally picked up before birth, by ultrasound. Ultrasound scans may detect the DWS cysts. A magnetic resonance imaging (MRI) scan is usually performed for detailed evaluation of the extent of DWS as can a computed tomography (CT) scan.

How is it treated?

Treatment for those with DWS consists of treating the associated problems.   A special tube to drain off excess fluid may be placed inside the skull. This will reduce ICP and help control swelling. Symptoms caused by elevated ICP can be relieved by shunt drainage of CSF. The shunt can be used for the cyst (cystoperitoneal), the ventricles (ventriculoperitoneal) or both.

With treatment, outlook for children is good. Around 50 per cent of those children affected will develop developmental delay (see entry Global developmental Delay).

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Most cases are sporadic (with no previous family history), but there is one per cent chance of recurrence in further pregnancies. Affected families should be referred to a genetic centre for advice and information.

Prenatal diagnosis
Ultrasound scan may detect the DWS cysts.

Is there support?

Information and support in the UK for Dandy-Walker syndrome is provided by SHINE (Spina Bifida•Hydrocephalus•Information•Networking•Equality; see entry Spina Bifida).

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