Spina bifida

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at March 14, 2016
StartDiseasesSpina bifida

Spina bifida, meaning, "split spine" is a physically disabling congenital birth defect caused by the failure of the spine to close while the infant is still in the womb. It is believed to be caused by a combination of genetic factors and environmental factors, though this is not known for certain. Spina bifida can occur anywhere along the spine and is the most common of neural tube defects (NTD), which refers to defects of the spine or brain.

Contents

Definition & Facts

There are, in the range of, 2,000 babies born each year in the U.S. with spina bifida. There are four distinct types of this birth defect:

  • Occult spinal dysraphism (OSD) occurs when the spinal cord is compressed in the spine and subsequently, there is neurological deterioration which transpires progressively.
  • Spina bifida occulta results when one or more vertebrae is imperfectly formed or has not developed completely.
  • Spina bifida cystica, also known as myelomeningocele is the most severe form of spina bifida. This is when there is an opening in the spine, and part of the spinal cord, membranes, and nerves push through, forming a sac. Three-quarters or more of these children also have fluid in the brain, causing pressure and swelling.
  • Meningocele is when the meninges project through the opening in the vertebrae. There is rarely nerve damage. These individuals tend to have only minor disabilities.

Symptoms & Complaints

There are symptoms of each type of spina bifida. However, the most severe form, myelomeningocele is the version most often referred to. Symptoms at birth include the protrusion or sac already mentioned. Often there is no skin covering the protrusion and it is visually obvious at birth.

In addition, the infant may experience seizures. Foot problems such as deformed feet are not uncommon, uneven hips, bladder and bowel problems, weak legs, paralysis and scoliosis (curvature of the spine) are also prevalent symptoms.

Spina bifida occulta often has no symptoms. However, sometimes there are indications that are found on the skin in the area just above the birth defect. There may be a conspicuous tuft of hair, what appears like a dimple, or birth mark, or an area of fat that is also somewhat conspicuous or out of place.

Indirect symptoms can include the occurrence of related health problems. This can include hydrocephalus which is head swelling due to extra fluid on the brain. It often causes brain damage. A latex allergy is common among children with spina bifida. Meningitis is a common health-related problem. The infant may suffer a tethered spinal cord which damages the back causing back pain. Difficulty completely emptying the bladder can result in chronic urinary tract infections (UTI) and kidney problems.

Causes

Although the exact cause of spina bifida remains elusive, medical science generally believes genetic, environmental and nutritional factors combined are at issue. A vitamin deficiency in the B-vitamin, folic acid by the mother, during pregnancy is one contributing factor.

A family history of NTD, neural tube defects, is likely a genetic cause of spina bifida. Some anti-seizure medications have been found to increase the risk of having a child with NTD. Another complication can arise when a woman’s body temperature rises excessively during the early weeks of pregnancy, causing hyperthermia.

Diagnosis & Tests

Diagnosis, the earlier the better, is often done prenatally, although many mild instances are not diagnosed until later and the very mildest may never be identified. There are prenatal screening tools available during the second trimester known as MSAFP, maternal serum alpha-fetoprotein. This is done at 16 to 18 weeks of gestation, as is ultrasound.

If the MSAFP test identifies an excessive amount of the protein AFP, it can indicate that alpha-fetoprotein has crossed the placenta into the mother’s bloodstream, and an NTD is present. Once identified, additional testing can confirm. This would include ultrasound and/or amniocentesis.

Mild forms of spina bifida occulta can be identified through a plain film X-ray, postnatally. In addition to a visual observation following delivery, there are additional postnatal tests that can be performed. These include CT scan, MRIs in order to view the vertebrae and spinal cord. A CT-scan or X-ray can identify hydrocephalus by seeing if there is cerebrospinal fluid on the brain.

Treatment & Therapy

Unfortunately, there is no known cure for spina bifida. For those infants born with myelomeningocele, the priority is to ensure that no infection ensues from the exposed nerves and tissues at the opening in the back, and to minimize any trauma to the area. Surgery is performed on the young infant almost immediately in order to close the opening in the back. In vitro natal surgery, considered experimental, is performed to close the defect as early as possible.

As many as half of children suffering myelomeningocele develop tethered cord syndrome also called progressive tethering. This is a condition where the spinal cord becomes attached or tethered to vertebrae or membranes. This causes the spinal cord to become stretched, in an abnormal way, during the child’s growth. Early surgery on the tethered cord will limit further deterioration.

Prevention & Prophylaxis

One preventive measure is to take 400 mcg of folic acid daily prior to and during pregnancy. It is known to aid in the development of a healthy fetus. There is no guarantee against spina bifida occurring; however, recent studies have shown that folic acid can reduce the likelihood of suffering NTD, including spina bifida.

It is advisable for any woman planning a pregnancy to discuss all medications that are taken with a doctor, including herbal supplements, to ensure they do not affect the likelihood of NTD.