What is spina bifida?
Spina bifida is a type birth defect often associated with folic acid deficiency in pregnancy. It is one type of nerve development problem known as neural tube defects in the baby. The neural tube is the structure from which the brain, spinal cord and the surrounding neurological tissue of the baby develops. The neural tube develops in the early phase of conception and its development is completed by the 28th day after conception.
In neural tube defect the neural tube fails to develop normally leading to defect in the spinal cord along with defect in the back bone. There are three principal forms of spina bifida of which myelomeningocele is the most common variety. Surgery is done to close the defect in the spinal cord but any nerve damage that already occurred is not reversible.
Types of Spina Bifida
There are three forms of spina bifida. These are :
- Spina bifida occulta is mildest form of spina bifida where there is small gap in between the vertebral bones. Almost no involvement of the nerves occur.
- Meningocele where the protective covering of the spinal cord push through the gap between the vertaebral bones without interrupting the growth of the nerves. Therefore surgical correction results into no or minimal damage to the nerves.
- Myelomeningocele is the most common and severe form of spina bifida. In this condition the spinal cord fails to close in the lower back region, most commonly involving the lumbar and sacral vertebra. Therefore through this gap the spinal cord along with its protective covering (meninges) protrude out forming a sac like structure externally.
Picture of myelomeningocele from Wikimedia Commons
Spinal Bifida Symptoms
Symptoms may vary and patients with a meningocele may not be aware of the condition until it is diagnosed incidentally. In spina bifida occulta the symptoms that may be present include :
- Abnormal tuft of hair growth externally on the skin overlying the affected spinal cord.
- Visible collection of fatty tissue.
- Visible dimple or birthmark (discolored skin).
The symptoms are more severe with a myelomeningocele. In most of these cases the sac is covered by skin but in some instances, the underlying nerves and other tissues may remain exposed to the environment. This increases the risk of infections. The common neurological defects associated with meningomyeolocele is weakness of limbs (paralysis), excessive accumulation of CSF in the brain (hydrocephalus), no control over bowel and bladder movement, repeated epileptic fits, abnormal curvature of the spine (scoliosis) and deformity in the feet. In some children there may be learning and speech difficulties along with poor intellectual capacity.
Causes of Spina Bifida
The exact cause of spina bifida is not conclusively known but according to most experts it is due to an interplay between genetic and environmental factors. A deficiency of folic acid is most often associated with spina bifida. This is further supported by the fact that risk of spina bifida decreases by 70% if the mother takes folic acid supplementation during pregnancy.
High Risk Mothers
Common risk factors include :
- Being White (Caucasian).
- Family history of neural tube defects
- Obesity (mother)
- Diabetes mellitus (mothe
- Intake of certain drugs like anti-epileptic drugs during pregnancy.
- High body temperature of the mother during first weeks of pregnancy.
Treatment of Spina Bifida
With greater knowledge about the risk factors associated with spina bifida and the importance of folic acid in pregnancy, spina bifida can be prevented. Women who are trying to conceive should start taking folic acid supplements early. The type of spina bifida determines the course of treatment. Spina bifida occulta does not require any treatment whereas surgical correction is required in other two varieties. In meningomyelocele, surgery does not reverse the nerve damage that has already occurred. Therefore the baby requires exercises and other therapies to improve the quality of life.