As many of you know I was not born with hydrocephalus. But 1 out 0f every 500 children are born with this incurable condition. It can be managed over a life time but what is the fetal hydrocephalus?
Fetal hydrocephal is when a blockage is caused where the CSF can't drain properly. Either the child was born unable to drain spinal fluid properly or there is a blockage.
Below you can read several different causes of fetal hydrocephalus.
The brain is constantly producing fluid (known as cerebrospinal fluid or CSF) as ... Aqueductal Stenosis - This is the most common form of fetal hydrocephalus, ...There is a narrow channel which connects the third and fourth ventricles of ... When this aqueduct is blocked, or was never properly formed, the CSF cannot drain...
Aqueductal Stenosis - This is the most common form of fetal hydrocephalus, and it is the form that our baby has. There is a narrow channel which connects the third and fourth ventricles of the brain to allow CSF to drain. This channel is called the Aqueduct of Sylvius. When this aqueduct is blocked, or was never properly formed, the CSF cannot drain properly and this condition is called aqueductal stenosis. Blockage of the aqueduct can be caused by a malformed aqueduct, a tumor, swelling due to infection or intraventricular bleeding. This blockage results in the enlargement of the ventricles. This type is generally not caused by chromosomal abnormalities.
X-Linked Aqueductal Stenosis - I put this in its own category because while it is caused by a blockage in the aqueduct, the reasons and associated outcomes are quite different. In this case the cause is a mutation in the L1CAM gene on Xq28. No, I don't know exactly what that means either, but I do know that it means that in addition to the problems caused by the pressure, you can expect other types of problems as well that are caused by the gene mutation. Many (but not all) babies with this type have abducted thumbs. Abducted thumbs can often be seen on an ultrasound and the doctor will probably look for this indicator if a diagnosis of hydrocephalus has been made.
X-Linked Aqueductal Stenosis is an x-linked recessive condition. There are two chromosomes that form a pair which determine gender in a person. For a boy the pair is made up of one X and one Y chromosome. For a girl the pair contains two X's. In order for a person to have a condition that is carried by a recessive chromosome, both chromosomes in the pair must have the genetic mutation that causes the condition. For this reason it is almost, but not quite, impossible for X-Linked Aqueductal Stenosis to be passed on to a girl. X-linked conditions are carried only on the X chromosome, and since boys only have one X chromosome, there is no second one to cancel it out. Therefore if a boy has the mutation in their X chromosome, they will have X-Linked Aqueductal StenosisAqueductal Stenosis. Since the mutation is extremely rare, the odds of having it in both the mother and father to pass down to the girl to form a pair of mutated chromosomes are very, very small.
Chiari Malformations - When the indented bony space at the lower rear of the skull, known as the posterior fossa, is smaller than normal, the cerebellum and brainstem can be pushed downward. The resulting pressure on the cerebellum can block the flow of cerebrospinal fluid causing hydrocephalus.
Normally the cerebellum, fourth ventricle and brainstem sit just above the foramen magnum, which is the opening in the bottom of the skull where the spinal cord attaches to the brainstem. There are several different degrees of Chiari Malformations, depending on how far down the cerebellum has been pushed.
Chiari I - where just a portion of the cerebellum has been pushed down into the spinal canal. A Chiari I may not have any symptoms, or may cause problems with balance, dizziness, blurred vision, loss of muscle strength or spasticity.
Chiari II - In this type not only has the cerebellum been pushed downward into the spinal canal, but so has the fourth ventricle and the medulla (lower portion of the brainstem). This type is generally associated with spina bifida (myelomeningocele) which is a condition where the spinal cord does not close properly before birth.
Chiari III - Portions of the cerebellum and/or brainstem are pushed out through a hole in the back or neck. This type has a high fetal and infant mortality rate, and a high rate of severe complications in those that survive. The hole defect is closed with surgery and a shunt is placed for the hydrocephalus. This form is very rare.
Chiari IV - An extremely rare form where the cerebellum does not fully form, and which is rarely survived.
For more information on Chiari malformations, please visit the following links:
Fetal hydrocephal is when a blockage is caused where the CSF can't drain properly. Either the child was born unable to drain spinal fluid properly or there is a blockage.
Below you can read several different causes of fetal hydrocephalus.
I will be honest I don't know all the if ands and buts to fetal hydrocephalus... It is still a learning processes for me... if you ever have any questions I have great resources to help you...
http://www.fetalhydrocephalus.com/hydro/info-Congenital-Hydrocephalus.aspx