SPINA BIFIDA – Types, Causes and Risk Factors, Diagnostic Evaluations, Management
This term is used to describe a series of birth defects affecting the spinal cord and central nervous system. Spina bifida (cleft spine) is a neural tube defect (a disorder involving incomplete development of the brain, spinal cord, and/or their protective coverings) caused by the failure of the fetus’s spine to close properly during the first month of pregnancy. In severe cases, the spinal cord protrudes through the back and may be covered by skin or a thin membrane.
TYPES OF SPINA BIFIDA
Spina bifida is the most common of a group of birth defects called neural tube defects. There are three types of spina bifida: spina bifida occulta, closed neural tube defect and spina bifida manifesta.
- Spina Bifida Occulta: Occulta is the mildest and most common form in which one or more vertebrae are malformed. The name “occulta”, which means “hidden”, indicates that the malformation, or opening in the spine, is covered by a layer of the skin. Spina bifida occulta does not usually cause any symptoms and most people are unaware that they have the condition. In such cases, no treatment is required. In other cases, some symptoms may be apparent, such as bladder and bowel problems, or scoliosis, which is an abnormal curvature of the spine.
- Closed Neural Tube Defects: Closed neural tube defects make up the second type of spina bifida. This form consists of a diverse group of spinal defects in which the spinal cord is marked by a malformation of fat, bone, or membranes. In some patients, there are few or no symptoms; in others the malformation causes incomplete paralysis with urinary and bowel dysfunction.
- Spina Bifida Manifesta: Spina Bifida Manifesta is the severe but rare form of this birth defect. If often is associated with nerve damage that can result in problems with walking, bladder control, and coordination. It can be separated into two classes, meningocele and myelomeningocele.
A. Spina Bifida Meningocele: Spina bifida meningocele is the rarest type of spina bifida. In this type of spina bifida, the meninges, which are the protective membranes that surround the spinal cord, are pushed out between openings in the vertebrae. The membranes can usually be removed during surgery and no further treatment is required. Some patients with meningocele may have few or no symptoms while others may experience symptoms similar to closed neural tube defects. In spina bifida meningocele, the nervous system is undamaged. However, a person with meningocele may develop other problems, including bladder and bowel problems.
B. Myelomeningocele: Myelomeningocele is the most serious type of spina bifida. In myelomeningocele, the spinal column remains open along several vertebrae (the disc shaped bones that make up the spine), resulting in partial or complete paralysis of the parts of the body below the spinal opening. The membranes and spinal cord push out to create a sac in the baby’s back. Sometimes the sac is covered with membranes called meninges, although it often remain open, leaving the nervous system vulnerable to infections that may be fatal. The paralysis may be so severe that the infected individual is unable to walk and may have urinary and bowel dysfunction.
CAUSES AND RISK FACTORS
The causes of spina bifida are unknown, although most experts agree that the condition is probably caused by a combination of environmental, nutritional and genetic (inherited) factors. Several risk factors for spina bifida have been identified. These are listed below:
- Folic acid deficiency
- Previous pregnancy with neural tube defects
- Family history of neural tube defects
- Use of certain anti-seizure medications; valproate, carbamazepine and lamotrigine
- Diabetes
- Obesity
- High temperatures in early pregnancy
- Excessive use of alcohol
- Exposure to certain chemicals
CLINCIAL MANIFESTATIONS
The symptoms will vary depending on the type of spina bifida, as mild forms carry almost no signs or symptoms at all. Effects can be different for every person.
In spina bifida occulta, there may be no symptoms or only a dimple, depression, birthmark, or hairy patch over the affected vertebrae. An abnormal tuft of hair, a collection of fat, a small dimple or a birthmark on the newborn’s skin above the spinal defect may be the only visible indication of the condition. Many people who have spina bifida occulta don’t even know it, unless the condition is discovered during a X-ray or other imaging test done for unrelated reasons.
In spina bifida manifesta, there may be swelling over the affected spine. If the nerves are damaged, the child may have problems with walking, bladder control, and coordination. The child may experience numbness and paralysis in the legs, and less commonly in the arms.
- Loss of bladder or bowel control
- Partial or complete lack of sensation
- Partial or complete paralysis of the legs
- Weakness of the hips, legs, or feet of a newborn
- Abnormal feet or legs, such as clubfoot
- Build up of fluid inside the skull (hydrocephalus)
- Hair at the back part of the pelvis called the sacral area
- Dimpling of the sacral area
- Learning disabilities
DIAGNOSTIC EVALUATIONS
- Quadruple screen
- Maternal serum alpha-fetoprotein (MSAFP) test
- Pregnancy ultrasound
- Amniocentesis
- Neurologic examination
- X-rays, ultrasound, CT, or MRI of the spinal area
MANAGEMENT
There is no cure for spina bifida. The nerve tissue that is damaged or lost cannot be repaired or replaced, nor can function be restored to the damaged nerves. Treatment depends on the type and severity of the disorder. Generally, children with the mild form need no treatment, although some may require surgery as they grow.
For the most severe cases of myelomeningocele, surgery is usually necessary to close the spinal gap and prevent infection. Prenatal surgery is also an option, to help close this spinal gap before the baby is born. Other treatment options include physical therapy, braces and crutches may be necessary to help children who have problems resulting from nerve damage. Braces can help treat joint or muscle problems, leading to increased mobility. If the infant has hydrocephalus, then a ventricular peritoneal shunt can help drain any extra fluid from the head. If urinary incontinence is a symptoms of more severe forms of spina bifida, the patient will need a catheter put in place to help regulate bladder infection.
Medication is usually not needed for the mildest forms of spinal bifida, but for more severe cases there are several options depending on symptoms. Antibiotics are administered to help prevent infections such as meningitis. Folic acid is given as a supplement to pregnant women to help prevent the incidence of spina bifida to begin with. Oxybutynin or other similar medications can also be given to children with spina bifida who suffer from incontinence. Physical therapy is one of the most important ways of helping your child to manage their condition and to make them as independent as possible. For spina bifida, the main aim of physical therapy is to prevent the child’s leg muscles from weakening.
SPINA BIFIDA – Types, Causes and Risk Factors, Diagnostic Evaluations, Management