Myelomeningocele Birth Defects

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What is myelomeningocele?

Myelomeningocele is a severe type of spina bifida where the spinal cord has no protection from the spine or the spinal canal. This birth defect happens when the vertebrae in a section of the spine do not fully form. The spinal cord and the meninges, which cover the spinal cord, protrude out of the back in a sac of fluid. Quite often, the spinal cord does not fully form at this point and there can be a loss of sensation or paralysis below this point.

What are the causes of myelomeningocele?

The basic cause of myelomeningocele is a neural tube defect. During the first weeks of pregnancy, the neural tube forms and eventually develops into the brain and spinal cord. If the neural tube does not fully close, the spinal cord and meninges may protrude through the underdeveloped spinal column. What causes this underdeveloped spinal column is unknown. Research is underway to identify the underlying causes. Focus is on genetic, nutritional, and environmental factors.

What are the risk factors for myelomeningocele?

The risks factors for an infant having myelomeningocele are the same as those for other forms of spina bifida. Since it is a neural tube birth defect, low levels of folic acid in the early stages of pregnancy in the mother is a known factor. Another factor is ethnic background. Hispanic women are more likely to have children with this defect that white women while white women are more likely than black women are.

Socio-economic and health conditions are also factors to consider. Those from lower socio-economic levels are more likely to have children with neural tube defects. Mothers who are obese or who are insulin-dependent are also more likely to have pregnancies with these defects.

What are the symptoms & signs of myelomeningocele?

With a myelomeningocele, one or more of the vertebrae do not fully form. This leaves an opening where the spinal cord and the surrounding meninges can protrude out through the opening. The most obvious sign is a sac along the spine that contains the spinal cord and the meninges. However, the symptoms are usually more serious. The spinal cord often does not develop properly below the point of protrusion. This can lead to paralysis or loss of sensation to some extent. Other symptoms can include loss of bladder or bowel control, abnormal legs or feet, hydrocephalus, and unusual hair growth or dimpling at the back part of the pelvis.

What are the diagnosis & tests for myelomeningocele?

Before birth, common tests can detect the potential presence of a neural tube defect like myelomeningocele. Elevated levels of alpha-fetoprotein after the first weeks of pregnancy can indicate this being an issue. Further testing with ultrasound and amniocentesis can help the diagnosis further.

However, in some cases, the real diagnosis does not happen until after birth. With the presence of the sac holding the spinal cord and meninges, the diagnosis is easier. Determining whether it is the less severe meningocele or this severe disorder is usually the only question after the visual determination of the sac.

What are the treatment options for myelomeningocele?

The first step in treatment with myelomeningocele is surgery to close the opening where the spinal cord and meninges protrude. This usually happens within a few hours or days of birth. This helps reduce the chances of infection and further damage to the spinal cord. After surgery, the treatment goes into giving the infant therapy. With this condition, some paralysis or loss of sensation is quite common. To combat this, therapy helps to strengthen the legs and give the child bowel and bladder control.

Later in life, further surgery may need to happen to keep the spinal cord from enmeshing with scar tissue. There may also be a need to correct other conditions related to this defect like lower extremity deformities.

What are the prognosis and expectations for myelomeningocele?

With myelomeningocele, many infants will have permanent paralysis or loss of sensation below the point where the vertebra does not develop properly. This will require further therapy and treatment throughout life. However, the length of life does not appear affected by this condition. Many go on to have fulfilling lives professionally and personally. While there can be further medical complications in later life, the quality of life is usually good.

What are the complications of myelomeningocele?

During birth, the presence of the myelomeningocele sac can cause problems with the delivery. This can lead to deprivation of oxygen during birth and in some cases lead to the development of cerebral palsy as a result. Some with this condition have other problems such as hydrocephalus, meningitis, and loss of bladder and bowel control. The paralysis and lack of sensation can cause problems later in life.

When should you call your health care provider regarding myelomeningocele?

As soon as there is a diagnosis of myelomeningocele, you need to call in specialists. Before birth, bringing in experts will give you options for treatment as quickly as possible. Even with diagnosis after birth, the experts will provide options and allow you to make an informed decision on treatment.

What can you do to prevent myelomeningocele?

Myelomeningocele is a neural tube defect. As with other such defects, upping the amount of folic acid is critical to preventing this defect. While it is not a guarantee, this increase can lower the probability of this happening up to 70%. Those with a history of children with this type of defect need to work with doctors before becoming pregnant again.


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