Fetal hydrocephalus

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Fetal hydrocephalus often refers to an extension of fetal ventriculomegaly~~where~~ where the ventricular dilatation is more severe. It is usually defined when the fetal lateral ventricular diameter is greater than 15 mm ¹.

Epidemiology

The estimated incidence is 0.5-3% per 1000 live births. There may be a very slight increased female predilection ¹⁰.

Pathology

It can be either obstructive or non-obstructive and each can arise from a number of aetiologies. ItIn a small proportion of cases it carries a familial X-linked inheritance (congenital X linked hydrocephalus).

Causes

in utero infection(s)

Associations

The vast majority of of conditions ~~are~~ are associated with other intracranial and cranial anomalies ⁵. The list includes:

central nervous system anomalies: (more common ⁶ and reported in more than 80% of cases)
- aqueductal stenosis: one of the commonest causative associations
- Chiari malformations
- neural tube defect(s)
- Dandy-Walker malformation
- encephalocoele
- alobar holoprosencephaly
- posterior fossa cysts
- polymicrogyria
non central nervous system anomalies
- craniofacial
  - cleft lip +/- palate
  - low set ears
  - bilateral optic atrophy
  - facial bone anomalies
  - acrocephalosyndactylia
- congenital cardiovascular anomalies
- gastrointestinal anomalies
- genitourinary anomalies
  - congenital renal fusion
- skeletal anomalies
  - clubfeet
syndromes
- Meckel-Gruber syndrome ¹⁰
- Miller-Dieker syndrome ¹⁰
chromosomal anomalies: may be present in ~20% of cases ¹⁰
- trisomy 21 ⁷
- triploidy ⁷

Radiographic features

Antenatal ultrasound

Will demonstrate enlarged ventricles with variable degrees of parenchymal thinning. The choroid may be seen floating within the ventricle giving a dangling choroid sign. Often a separation of more than 3 mm between the choroid plexus and the margin of the ventricle in considered abnormal. In some cases, there may also be evidence of macrocephaly.

Treatment and prognosis

The overall prognosis ~~with~~will depend inon the underlying cause and associated anomalies. Some cases can slowly progress during the fetal period. Antenatal shunting has been considered in a small proportion of selected cases ².

-<p><strong>Fetal hydrocephalus</strong> often refers to an extension of <a href="/articles/fetal-ventriculomegaly">fetal ventriculomegaly </a>where the ventricular dilatation is more severe. It is usually defined when the fetal lateral ventricular diameter is greater than 15 mm <sup>1</sup>.</p><h4>Epidemiology</h4><p>The estimated incidence is 0.5-3% per 1000 live births. There may be a very slight increased female predilection <sup>10</sup>.</p><h4>Pathology</h4><p>It can be either obstructive or non-obstructive and each can arise from a number aetiologies. It a small proportion of cases it carries a familial X-linked inheritance (<a href="/articles/congenital-x-linked-hydrocephalus">congenital X linked hydrocephalus</a>).</p><h5>Causes</h5><ul><li><a href="/articles/in-utero-infection">in utero infection(s)</a></li></ul><h5>Associations</h5><p>The vast majority of of conditions are are associated with other intracranial and cranial anomalies <sup>5</sup>. The list includes:</p><ul>
+<p><strong>Fetal hydrocephalus</strong> often refers to an extension of <a href="/articles/fetal-ventriculomegaly">fetal ventriculomegaly</a> where the ventricular dilatation is more severe. It is usually defined when the fetal lateral ventricular diameter is greater than 15 mm <sup>1</sup>.</p><h4>Epidemiology</h4><p>The estimated incidence is 0.5-3% per 1000 live births. There may be a very slight increased female predilection <sup>10</sup>.</p><h4>Pathology</h4><p>It can be either obstructive or non-obstructive and each can arise from a number of aetiologies. In a small proportion of cases it carries a familial X-linked inheritance (<a href="/articles/congenital-x-linked-hydrocephalus">congenital X linked hydrocephalus</a>).</p><h5>Causes</h5><ul><li><a href="/articles/in-utero-infection">in utero infection(s)</a></li></ul><h5>Associations</h5><p>The vast majority of conditions are associated with other intracranial and cranial anomalies <sup>5</sup>. The list includes:</p><ul>
~~-<li><a href="/articles/encephalocoele">encephalocoele</a></li>~~
+<li><a href="/articles/encephalocele-1">encephalocoele</a></li>
-</ul><p>See also: <a href="/articles/congenital-syndromes-associated-with-enlarged-ventricles">congenital syndromes associated with enlarged ventricles</a>.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><p>Will demonstrate enlarged ventricles with variable degrees of parenchymal thinning. The choroid may seen floating within the ventricle giving a <a href="/articles/dangling-choroid-sign">dangling choroid sign</a>. Often a separation of more than 3 mm between the choroid plexus and the margin of the ventricle in considered abnormal. In some cases, there may also be evidence of <a href="/articles/macrocephaly">macrocephaly</a>.</p><h4>Treatment and prognosis</h4><p>The overall prognosis with depend in the underlying cause and associated anomalies. Some cases can slowly progress during the fetal period. Antenatal shunting has been considered in a small proportion of selected cases <sup>2</sup>.</p>
+</ul><p>See also: <a href="/articles/congenital-syndromes-associated-with-enlarged-ventricles">congenital syndromes associated with enlarged ventricles</a>.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><p>Will demonstrate enlarged ventricles with variable degrees of parenchymal thinning. The choroid may be seen floating within the ventricle giving a <a href="/articles/dangling-choroid-sign">dangling choroid sign</a>. Often a separation of more than 3 mm between the choroid plexus and the margin of the ventricle in considered abnormal. In some cases, there may also be evidence of <a href="/articles/macrocephaly">macrocephaly</a>.</p><h4>Treatment and prognosis</h4><p>The overall prognosis will depend on the underlying cause and associated anomalies. Some cases can slowly progress during the fetal period. Antenatal shunting has been considered in a small proportion of selected cases <sup>2</sup>.</p>