Dandy-Walker syndrome

Dandy-Walker syndrome is a rare and quite severe malformation of the cerebellum and fourth ventricle. It is considered a congenital anomaly in children and is common with a frequency of 1:25,000. This defect is characterized by underdevelopment or hypoplasia of the cerebellar vermis, cystic dilation of the fourth ventricle and dilation of the posterior cranial fossa. The syndrome may be accompanied by multiple anomalies of other organs, but the main ones are the 3 listed above. Approximately 70-90% of patients have hydrocephalus, which often develops immediately after birth. Fortunately, the pathology can be detected even during pregnancy.

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Causes Dandy-Walker syndrome

Unfortunately, even modern medicine cannot yet answer with certainty the question of what causes the development of Dandy-Walker syndrome. Of course, there are some risk factors that in one case or another can lead to intrauterine defects. The following play an important role in the formation of this anomaly:

1. Viral diseases that the mother suffers from during pregnancy (especially beware of infections in the first three months).
2. Cytomegalovirus infection.
3. Rubella.
4. Diabetes mellitus or other diseases associated with metabolic disorders in the expectant mother.

Quite often, various fetal pathologies during intrauterine development appear in women who suffer from alcoholism or drug addiction. In most cases, it is such mothers who give birth to children with Dandy-Walker syndrome. If during an ultrasound the doctor sees that the fetus is developing abnormally, he recommends terminating the pregnancy. In very rare cases, Dandy-Walker syndrome develops for hereditary reasons.

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Pathogenesis

Dandy-Walker syndrome was first described by Dandy and Blackfan in 1914. Since the initial description, additional studies have been conducted that have described the various morphological features of this defect.

Research by D'Agostino in 1963 and Hart in 1972 identified the characteristic triad of Dandy-Walker syndrome, namely:

1. Complete or partial agenesis of the worm
2. Cystic dilatation of the fourth ventricle
3. Enlargement of the posterior cranial fossa with upward displacement of the lateral paranasal sinuses and cerebellum.

This triad is usually associated with supratentorial hydrocephalus, which are complications and not part of the malformation complex.

Classically, cystic malformations of the posterior fossa are divided into Dandy-Walker syndrome, Dandy-Walker variant, mega cisterna magna, and posterior fossa arachnoid cyst - these malformations make up the Dandy-Walker complex.

The Dandy-Walker variant combines vermis hypoplasia and cystic dilatation of the fourth ventricle, without enlargement of the posterior fossa.

This syndrome is a congenital pathology, which is expressed in the fact that the cerebrospinal fluid pathways and the cerebellum do not fully develop. Most of all, the anomaly concerns the openings that connect the two ventricles (the third and fourth) with the large cistern of the brain, and those that connect these same ventricles with the subarachnoid space of the meninges. Due to the violation of the cerebrospinal fluid outflow, a cerebrospinal fluid cystic formation occurs in the posterior cranial fossa and obstructive hydrocephalus as a result of secondary cystic dilatation of the fourth ventricle (70-90% of cases).

Associated with Dandy-Walker anomaly malformations of the central nervous system (70% of cases):

• Dysgenesis of the corpus callosum (20-25%).
• Lipoma of the corpus callosum.
• Holoprosencephaly (25%).
• Porencephaly.
• Cingulate dysplasia (25%).
• Schizencephaly.
• Polymicrogyria/gray matter heterotopia (5-10%).
• Cerebellar heterotopia.
• Occipital encephalocele (7%).
• Microcephaly.
• Dermoid cyst.
• Malformations of the cerebellar lobules (25%).
• Malformations of the inferior olivary nucleus.
• Hamartoma in a gray tubercle.
• Syringomyelia.
• Klippel-Feil deformation.
• Spina bifida.

Other rare associated CNS malformations (20-33% of cases):

• Orofacial and palate deformities (6%).
• Polydactyly and syndactyly.
• Anomalies of cardiac development.
• Urinary tract abnormalities (polycystic kidney disease).
• Retinal cataract, choroidal dysgenesis, coloboma.
• Hemangioma on the face.
• Hypertelorism.
• Meckel-Gruber syndrome.
• Neurocutaneous melanosis.

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Symptoms Dandy-Walker syndrome

This abnormality in the development of the child can be seen with the help of an ultrasound examination already in the first months of pregnancy. In particular, all the symptoms of this disease are visible already at 20 weeks. The main evidence of the development of the pathology are various signs of brain damage: cysts in the cranial fossa are clearly visible, the cerebellum is poorly developed, the fourth ventricle is too dilated. At the same time, the ultrasound signs become more distinct as the fetus develops.

Over time, clefts in the hard palate and lip, abnormal kidney development, and syndactyly appear. If for some reason an ultrasound was not performed during pregnancy, the symptoms of the disease become clearly visible immediately after the birth of the child. Due to high pressure inside the skull, such children are very restless. They develop hydrocephalus with muscle spasms, nystagmus. In some cases, there may be no signs of hydrocephalus.

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First signs

1. Atresia of the foramina of Magendie and Luschka (closure or congenital absence).
2. The posterior part of the cranial fossa increases in size.
3. Atrophy of the cerebellar hemispheres.
4. Cystic formations appear, including fistulas.
5. Hydrocephalus of varying degrees.

All these first signs are clearly visible during the ultrasound of the fetus. That is why it is so important for pregnant women to undergo all tests and examinations on time.

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Dandy-Walker syndrome in children

A priori, Dandy-Walker syndrome is considered a childhood disease. Fortunately, it is quite rare (only one case per 25,000 newborn babies). Its symptoms can be seen in the womb, but if for some reason this was not done, then children with this disease develop quite strong and severe complications with age.

Over time, noticeable cerebellar symptoms appear. In older children, coordination of movements begins to be impaired, so it is quite difficult for them to move and walk (sometimes even impossible). The main symptom is severe mental retardation, which is almost impossible to cure. Associated problems also appear: kidney disease, heart disease, abnormal development of fingers, face, hands, poor eyesight.

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Dandy-Walker syndrome in adults

Dandy-Walker syndrome is an anatomical and clinical variant of vicious hydrocephalus. This disease is characterized by atresia of the openings in the brain, as well as dilation of the ventricles (third and fourth).

Despite the fact that this pathology is considered congenital, in very rare cases its first signs begin to appear in early childhood (age four) or even later. For a long time, there are no symptoms of this congenital defect. Decompensation sometimes occurs only in school-age children or adolescents. Exceptional cases are when the first symptoms of Dandy-Walker syndrome appear in adults.

Among the main symptoms of the disease in adults, the following can be distinguished:

1. The size of the head gradually increases.
2. The bones of the back of the head begin to protrude: they seem to bulge out.
3. Coordination of movements is severely impaired, and unclear and sweeping movements appear.
4. Nystagmus develops, which manifests itself in oscillatory movements of the eyes from side to side.
5. Frequent seizures with convulsions.
6. Muscle tone increases greatly (sometimes to the point of spasticity). The muscles are in constant tension.
7. The development of mental retardation, which manifests itself in the fact that a person does not recognize relatives, has difficulty reading and distinguishing letters, and cannot write.

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Dandy-Walker syndrome in pregnancy

Typically, Dandy-Walker syndrome can be seen by ultrasound as early as 18-20 weeks of pregnancy. During this period, complete or partial agenesis of the cerebellar vermis may be noticeable. In very rare cases, prenatal diagnosis of this disease is possible at an earlier stage.

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Forms

There are two forms of Dandy-Walker syndrome, which differ in the degree of anatomical impairment:

1. Complete form - underdevelopment of the cerebellar vermis is complete.
2. Incomplete form – only part of the cerebellum develops incorrectly.

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Complications and consequences

Of course, many congenital pathologies are very serious, but Dandy-Walker syndrome is considered one of the most severe anomalies in children. This disease leads to quite complex consequences:

1. The mental defect remains for life.
2. Often, a neurological defect also remains: muscle tone is increased, and coordination of movements is incorrect.
3. A fatal outcome can be expected in most cases.

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Diagnostics Dandy-Walker syndrome

First of all, the doctor diagnoses the complaints and the medical history (if Dandy-Walker syndrome appears after birth). This stage includes answers to some questions:

1. Has anything like this happened in your family before?
2. At what age did the first signs of the disease begin to appear?
3. When did coordination of movements begin to be disrupted, the head to grow, and muscle tone to change?

Next, the specialist should conduct a neurological examination. During this stage, one can see the development of nystagmus (involuntary oscillatory movements of the eyes in different directions), bulging of the fontanelle, decreased muscle tone, and an increase in head size.

Conducting an ultrasound examination during pregnancy helps to see the first signs of the syndrome in the fetus. In addition, this same method can be used in the later stages of the disease to check the heart for defects.

By conducting MRI (magnetic resonance imaging) of the brain, it is possible to see the degree of increase in head size, the appearance of a cyst in the posterior cranial fossa, enlargement of the ventricle, abnormal development of the cerebellum, and hydrocephalus.

In some cases, it is necessary to consult a neurosurgeon or a medical geneticist.

Instrumental diagnostics

The most common methods of instrumental diagnostics for detecting the first symptoms of Dandy-Walker syndrome are ultrasound (ultrasound examination of the fetus) and MRI (magnetic resonance imaging). As a rule, abnormal development of the child is noticeable during the first ultrasound, which is performed at 18-20 weeks of pregnancy. If the specialist cannot make an accurate diagnosis or its confirmation is necessary, he or she may prescribe an MRI. The diagnosis made with the help of MRI is 99% accurate.

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Differential diagnosis

Differential diagnostics of Dandy-Walker syndrome is usually performed with the expansion of the large cistern of the brain, which develops with inflammatory or toxic hypoplasia of the cerebellum, as well as with a retrocerebral cyst. But here it is worth considering that with Dandy-Walker syndrome, the cerebellar vermis has a pathognomonic defect that is not observed with other hypoplasia. To perform differential diagnostics of this pathology with arachnoid cysts, it is necessary to do MRI.

Treatment Dandy-Walker syndrome

Dandy-Walker syndrome has varying degrees of severity. As a rule, children who are born with a severe form of this anomaly die in the first month of life. If the defect is compatible with life, then the child's mental development is considered very problematic. Parents should be prepared for the fact that the child will have very low intelligence, which cannot be changed with the help of remedial education. The prognosis for the development of a child with Dandy-Walker syndrome is extremely unfavorable.

There is practically no point in treating such an anomaly. But if hydrocephalus begins to increase, then surgical intervention is required. Intracranial pressure can be reduced by shunting the fourth ventricle of the brain.

Treatment for Dandy-Walker syndrome can only be symptomatic. The child's mental retardation cannot be corrected, the motor functions of the body are severely impaired, so such children usually cannot sit or stand independently.

When treating, it is very important to remember about concomitant diseases of the heart, kidneys, maxillofacial pathology. They often require qualified medical intervention.

If a doctor detects this anomaly in a fetus, the parents must make a rather difficult choice: terminate the pregnancy or give birth to a child who will suffer from an incurable pathology for the rest of his life.

Surgical treatment

The only surgical treatment for Dandy-Walker syndrome is the shunting method, which helps reduce the severity of hydrocephalus symptoms and improve the outflow of cerebrospinal fluid.

Prevention

Since Dandy-Walker syndrome is a hereditary disease, it is considered pointless to carry out its prevention. It is recommended to visit an obstetrician-gynecologist regularly during pregnancy (once a month during the first trimester, once every two to three weeks during the second trimester, and once every seven to ten days during the third trimester). Try to register with a women's health clinic in a timely manner (before the 12th week of pregnancy).

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Forecast

The prognosis for Dandy-Walker syndrome is catastrophically unfavorable. In 50% of cases, the child dies in the first year of life. Those children who survive must be constantly under the watchful eye of doctors. They have an extremely low level of intelligence, which is not subject to correction. The syndrome occurs with a pronounced functional neurological status.

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Disability

Congenital defects of the central nervous system, in particular Dandy-Walker syndrome, lead to severe disability from the first minutes of life.

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