The severity of the symptoms depends on the location and size of the opening in the spine and part of the spinal cord and nerves that are affected.
Spina bifida occulta is a birth defect that occurs due to the malformation of the baby’s spine during pregnancy. In this condition, one or more vertebrae do not close properly. This results in the baby being born with small gaps in the bones of the spine that can expose the sensitive spinal cord to any injury. It affects about 10-20% of people. In most cases, it causes no symptoms and health problems at all. Occasionally, it causes symptoms if the defect is severe involving more than one bone. These symptoms could be caused by a tethered cord. A tethered cord is a spinal cord that cannot move freely inside the spinal canal. The movement is typically restricted at the base of the spinal cord. Sometimes, a tethered cord needs to be released through surgery. An untreated tethered cord can cause progressive damage to the spinal cord.
The severity of the symptoms depends on
- The location and size of the opening in the spine.
- Part of the spinal cord and nerves are affected.
Symptoms of spina bifida occulta: A small number of people with more severe spina bifida occulta may have some of the following symptoms:
- A thick patch of the hair, dimple, or birthmark at the base of the spine (lower back)
- Leg weakness, clumsiness, or numbness
- Pain and trouble walking
- Deformity of the foot
- Bowel or bladder dysfunction
- Numbness or weakness of the hand
What are the three types of spina bifida?
There are three types of spina bifida:
- Myelomeningocele: This is the most serious type of spina bifida. In this condition, a sac containing part of the spinal cord, it’s covering, and spinal fluid pushes through the gap in the spine and skin and is visible on the baby’s back. The part of the spinal cord and nerves in this sac is damaged. This type of spina bifida causes moderate to severe disabilities such as loss of sensations in the legs or feet, inability to move the legs, and bowel and bladder disturbances.
- Meningocele: In this condition, a sac that contains the spinal fluid pushes through an opening on the baby’s back. The spinal cord is in its normal place in the spinal canal. There is little or no nerve damage. The skin over the meningocele is often open. This type of spina bifida causes minor disabilities.
- Spina bifida occulta: This is the mildest type of spina bifida. In this condition, there no sac on the back. The spinal cord and nerves are usually normal and do not cause any disabilities. Many times, spina bifida occulta may not be diagnosed until late childhood or early adulthood.
What causes spina bifida occulta?
The exact causes of spina bifida occulta are unknown. Both environmental and genetic factors have been found to play a role.
A woman is more likely to have a baby with spina bifida occulta if she
- Has a family history of spina bifida occulta.
- Takes certain medicines during pregnancy.
- Already has had a baby with spina bifida.
- Has health conditions such as obesity and diabetes.
- Has folic acid deficiency during early months of pregnancy.
How is spina bifida occulta diagnosed?
Spina bifida occulta usually doesn't cause symptoms. Usually, it is an incidental finding when an X-ray or other imaging study of the spine is done for a different reason.
Sometimes, spina bifida occulta is diagnosed using ultrasound after a visible sign is observed on the skin directly over the defect such as a large dimple, a patch of thick hair, a growth, an unusual pigment, or a red patch at the base of a baby's spine.
If neurological symptoms associated with a tethered cord are present, a magnetic resonance imaging (MRI) scan may be done to examine the spinal cord.
How is spina bifida occulta treated?
When spina bifida occulta causes no symptoms, it requires no medical treatment.
Babies with a tethered cord may require surgery to release the tether and let the spinal cord move more freely.