Spina bifida or Cleft Spine
Spina bifida is a birth defect that involves the incomplete development of the spinal cord or its coverings. The term spina bifida means “split” or “open” spine. Spina bifida is part of a group of birth defects called neural tube defects. The neural tube is the embryonic structure that eventually develops into the baby’s brain and spinal cord and the tissues that enclose them. Most children who have spina bifida do not have problems from it
Spina bifida occurs at the end of the first month of pregnancy when the two sides of the embryo’s spine fail to join together, leaving an open area. In some cases, the spinal cord or other membranes may push through this opening in the back. The condition usually is detected before a baby is born and treated right away. Other neural tube defects include amencephaly, a condition in which the portion of the neural tube which will become the cerebrum does not close, and encephalocele, which results when other parts of the brain remain unfused.
What causes spina bifida
The exact cause of this birth defect is not known. Genes and environment factors are said to be the most important cause women who have had one child with spina bifida are more likely to have another child with the disease environmental factors, such as nutrition and exposure to harmful substances, probably contribute to spina bifida. Spina bifida does seem to run in families, spina bifida can be prevented by adequate intake of folic acid. Folic acid, one of the B vitamins that is a key factor in the synthesis (the making) of nucleic acid (DNA and RNA). before and during early pregnancy people with spina bifida appear to have abnormal metabolism of folic acid. spina bifida may be an inborn defect in folic acid metabolism rather than a simple deficiency in this nutrient. A high fever during pregnancy may increase a woman’s chances of having a baby with spina bifida. Women with epilepsy who have taken the drug valproic acid to control seizures may have an increased risk of having a baby with spina bifida.
Types of spina bifida
The different types of spina bifida are—-
1) spina bifida occulta
2) spina bifida cystica
spina bifida occulta
“occulta means hidden, defect is not visible or without symptoms. This is the mildest forms of spina bifida. In occulta, the outer part of some of the vertebrae are not completely closed. The split in the vertebrae is so small that the spinal cord does not protrude. The skin at the site of the lesion may be normal, or it may have some hair growing from it; there may be a dimple in the skin, or a birthmark Most children with this type of defect never have any health problems, and the spinal cord is often unaffected. Spina bifida occulta is rarely linked with complications or symptoms. Spina bifida occulta is usually discovered accidentally when the person has an x-ray or MRI for some other reason
Spina bifida cystica
In spina bifida cystica, a cyst protrudes through the defect in the vertebral arch. spina bifida cystica may result in hydrocephalus and neurological deficits
The least common form of spina bifida is a posterior meningocele (or meningeal cyst involves the meninges, the membranes responsible for covering and protecting the brain and spinal cord. If the meninges push through the hole in the vertebrae (the small, ring-like bones that make up the spinal column), the sac is called a meningocele Fluid leaks out of the spine and pushes against the skin. You may see a bulge in the skin. In many cases, there are no other symptoms..In a posterior meningocele, the vertebrae develop normally, however the meninges are forced into the gaps between the vertebrae. As the nervous system remains undamaged, individuals with meningocele are unlikely to suffer long-term health problems, Symptoms can vary from none to partial paralysis, but these cysts can sometimes be removed with surgery, allowing the child to develop normally.
is the most severe form of spina bifida. It occurs when the meninges push through the hole in the back, and the spinal cord also pushes though. Most babies who are born with this type of spina bifida also have hydrocephalus, an accumulation of fluid in and around the brain. ecause of the abnormal development of and damage to the spinal cord, a child with myelomeningocele typically has some paralysis. The degree of paralysis largely depends on where the opening occurs in the spine. The higher the opening is on the back, the more severe the paralysis tends to be. Part of the spinal nerves push out of the spinal canal, and you may see a bulge in the skin. The nerves are often damaged, which can cause problems with walking, bladder or bowel control, and coordination. In some babies, the skin is o pen and the nerves are exposed . this is the type of spina bifida that causes the vast majority of disability. The exposure of these nerves and tissues make the baby more prone to life-threatening infections. Many individuals with spina bifida will have an associated abnormality of the cerebellum, called the Arnold Chiari II malformation In affected individuals the back portion of the brain is displaced from the back of the skull down into the upper neck.
Risk factors of spina bifida
- Race. Spina bifida is more common among whites and Hispanics.
- Family history of neural tube defects. Couples who’ve had one child with a neural tube defect have a slightly higher chance of having another baby with the same defect
Folate deficiency. Folate (vitamin B-9) is important to the healthy development of a fetus. Folate is the natural form of vitamin B-9. The synthetic form, found in supplements and fortified foods, is called folic acid. A folate deficiency increases the risk of spina bifida and other neural tube defects
- Some medications. Anti-seizure medications, such as valproic acid (Depakene), seem to cause neural tube defects when taken during pregnancy, perhaps because they interfere with the body’s ability to use folate and folic acid.
- Diabetes. Women with diabetes who don’t control their blood sugar well have a higher risk of having a baby with spina bifida.
- Obesity. Pre-pregnancy obesity is associated with an increased risk of neural tube birth defects, including spina bifida.
- Increased body temperature. Some evidence suggests that increased body temperature (hyperthermia) in the early months of pregnancy may increase the risk of spina bifida.
Signs and symptoms of spina bifida
child’s symptoms will depend on how severe the defect is.
Spina bifida occurs in three forms, each varying in severity:
Spina bifida occulta. This mildest form results in a small separation or gap in one or more of the bones (vertebrae) of the spine. Because the spinal nerves usually aren’t involved, most children with this form of spina bifida have no signs or symptoms and experience no neurological problems. An abnormal tuft of hair, a collection of fat, a small dimple o a birthmark on the newborn’s skin above the spinal defect may be the only visible indication of t he condition.
Meningocele. In this rare form, the protective membranes around the spinal cord (meninges) push out through the opening in the vertebrae. abies who are born with the meningocele form have a fluid-filled sac visible on the back. The sac is often covered by a thin layer of skin and can be as small as a grape or as large as a grapefruit.
Myelomeningocele n myelomeningocele, the baby’s spinal canal remains open along several vertebrae in the lower or middle back. Because of this opening, both the membranes and the spinal cord protrude at birth, forming a sac on the baby’s back. In some cases, skin covers the sac. Usually, however, tissues and nerves are exposed, making the baby prone to life-threatening infections.
Neurological impairment — often including loss of movement (paralysis) — is common. So are bowel and bladder problems, seizures and other medical complications. Many children who have severe spina bifida develop an allergy to latex (a type of rubber) Spine, hip, foot, and leg deformities are often due to imbalances in The most common bladder and bowel problems are inability to voluntarily relax the muscles (sphincters) that hold urine in the bladder and muscle strength and function resulting mostly from residual paralysis . there is foot or leg deformities, hip dislocation, or scoliosis.
Diagnosis of spina bifida
Pregnant woman can have a blood test (maternal serum triple or quadruple screen) and a fetal ultrasound to check for spina bifida and other problems with the fetus.
If test results suggest a birth defect, she can choose to have an amniocentesis. This test helps confirm if spina bifida exists. But the test also has risks, such as a chance of miscarriage.
Treatment of spina bifida
Treatment depends on how severe the defect is. Most children with spina bifida have only a mild defect and may not need treatment. But a child with a severe defect may need surgery. If child has problems from nerve damage, he or she may need a brace or a wheelchair, physical therapy, or other aids. If y child has bladder control problems, he can use a catheter each day. It can help prevent infection and kidney damage in the child , child has little or no feeling in the limbs and can’t sense pain, he or she may get injured and not know it. the need is to check the child’s skin each day for cuts, bruises, or other sores. A baby who also has hydrocephalus will need an operation to place a shunt in the brain. The shunt is a thin tube that helps to relieve pressure on the brain by draining and diverting extra fluid. Most affected individuals will need to use braces, crutches walkers or wheelchairs to maximize their mobility
Article publié pour la première fois le 10/07/2011