Spina bifida: causes, diagnosis and treatments


Spina bifida: causes, diagnosis and treatments

Spina bifida is a congenital malformation (birth defect) in which there is something wrong with the bone in the vertebral column, exposing the spinal cord which should be protected within the vertebral column.

Spina bifida is caused by the incomplete closing of the embryonic neural tube. The term "spina bifida" comes from the Latin "spina" meaning "spine", and "bifida" meaning "split."

In this article, we will discuss the causes, symptoms and treatments of spina bifida.

Here are some key points about spina bifida. More detail and supporting information is in the main article.

  • Spina bifida is a birth defect involving the spinal column
  • Myelomeningocele is the most serious type of spina bifida
  • Roughly 1 in 1,000 babies are born with myelomeningocele spina bifida
  • In spina bifida, the spinal column is more susceptible to infections because it is exposed
  • Patients create too much cerebrospinal fluid which can build up and result in hydrocephalus
  • Hydrocephalus increases the chances of learning difficulties
  • The exact causes of spina bifida are not known
  • Most spina bifida patients have bowel and urinary incontinence
  • Women with diabetes are more likely to have a baby with spina bifida.

What is spina bifida?

During the first month after conception, the embryo develops a primitive tissue structure known as the neural tube. Gradually, this structure develops into bones, nerves and tissue which eventually form the nervous system and spine.

Spina bifida is a birth defect that impacts the spine.

When the unborn baby has spina bifida something goes wrong with the neural tube and spinal column development - it does not close fully. The spinal column is a ridge of bone that protects and surrounds the nerves.

There are three main types of spina bifida:

  • Spina bifida occulta
  • Spina bifida meningocele
  • Myelomeningocele.

This text refers mainly to myelomeningocele.

Myelomeningocele is the most serious type and affects approximated 1 in every 1,000 babies born. Along several vertebrae the spinal column remains exposed. A sac forms on the baby's back as the membranes and spinal cord push out. The sac may be covered with meninges (membranes).

The nervous system is more susceptible to infections, some of which can be life-threatening. Although surgery can correct the defect, it cannot reverse the extensive damage that has already occurred. The baby can have partly or totally paralyzed legs, urinary and/or bowel incontinence, and can lose sensation of the skin.

The majority of patients have excessive CSF (cerebrospinal fluid) - a condition known as hydrocephalus. CSF is a watery fluid which flows through the cavities (ventricles) inside the brain and also around the surface of the brain and spinal cord.

In cases of babies with spina bifida, the accumulation of CSF is caused because the neural tube did not develop properly. Hydrocephalus can result in brain damage, so the built up pressure needs to be alleviated by surgery.

As treatment options have improved, so has the outlook for babies with spina bifida. About 50 years ago the majority of babies would not survive beyond their first twelve months. Nowadays, most patients survive well into adulthood. A considerable number of adults with spina bifida can live independently.

Symptoms of spina bifida?

If the opening occurs at the top of the spine, the patient's legs are more likely to be completely paralyzed, and there will be other problems with movement elsewhere in the body. If the openings are in the middle or the base of the spine, symptoms tend to be less severe.

Myelomeningocele

Myelomeningocele is the most severe form of spina bifida. Those with hydrocephalus have a greater chance of having learning problems.

Cognitive symptoms - problems occurring in the neural tube have a negative effect on brain development. The main part of the brain (cortex), especially the frontal part does not develop properly, leading to some cognitive problems. Cognitive refers to cognition; the process of awareness, thinking, learning, judging and knowing.

There may also be Type 2 Arnold-Chiari malformation, an abnormal brain development involving the cerebellum - this may affect the patient's language processing and physical coordination skills.

Approximately 60% of people with spina bifida will have average intelligence. A significant percentage of those with normal intelligence will have some kind of learning disability which may include problems with attention, solving problems, reading, understanding spoken language, making plans, and grasping abstract concepts. There may also be problems with visual and physical coordination, such as doing up buttons or shoelaces.

Most patients have some degree of paralysis in their legs. In cases of partial paralysis, leg braces or a walking stick may be necessary. When paralysis is total, the patient will need a wheelchair. If the lower limbs are not exercised they can become weak, which can eventually lead to dislocated joints and misshapen bones.

Most patients have bowel and urinary incontinence.

Spina bifida occulta

Spina bifida occulta is the mildest form. Most patients have no neurological signs or symptoms. There may be a small birthmark, dimple or tuft of hair on the skin where the spinal defect is. A considerable number of patients with this type of spina bifida never know they have it until an imaging test taken for another reason is done.

Meningocele

In meningocele (open spina bifida) the spinal cord develops normally, the meninges (protective membranes around the spinal cord) push through the opening in the vertebrae. The membranes are surgically removed, usually with no damage to nerve pathways, or very little damage.

Causes of spina bifida

Nobody is completely sure what causes spina bifida. Scientists say it is most likely due to a combination of inherited (genetic), environmental and nutritional factors.

There is some evidence that low intake of plant proteins and folic acid play a role in spina bifida.

Women who do not have enough folic acid during the pregnancy have a higher chance of giving birth to a baby with spina bifida. Experts say that women of reproductive age should make sure their folic acid intake is adequate. Nobody is sure how folic acid intake prevents spina bifida from developing.

A study reported in the Journal of Nutrition concluded that "Low preconceptional intakes of plant proteins, iron, magnesium, and niacin are associated with a 2- to 5-fold increased risk of spina bifida."1

If a woman gives birth to a baby with spina bifida, she has a higher-than-normal risk of having another baby with spina bifida too (about 5% risk).

Some medications, such as some for treating epilepsy or bipolar disorder have been associated with a higher risk of giving birth to babies with congenital defects, such as spina bifida.

Women with diabetes are more likely to have a baby with spina bifida, compared to other females.

Obese women, those whose BMI (body mass index) is 30 or more have a higher risk of having a baby with spina bifida. The higher the woman's BMI is over 30, the higher the risk.


On the next page, we look at testing for and diagnosing spina bifida, along with treatment options.

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Spina bifida (myelomeningocele, meningocele, occulta) - causes, symptoms, treatment (Video Medical And Professional 2018).

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