Spina Bifida

Spina bifida is a birth defect where a baby's spinal cord and backbone do not fully form or close during early pregnancy. It is a type of neural tube defect that can range from mild with no symptoms to severe, causing nerve damage, physical disabilities, and other health challenges. Early diagnosis and treatment are crucial for managing its effects.

What is Spina Bifida?

Spina bifida is a birth defect that happens when a baby's spinal cord and the bones around it (vertebrae) do not fully close during the first month of pregnancy. This condition, a type of neural tube defect, can lead to varying degrees of nerve damage and physical challenges, depending on its severity and location along the spine.

During the first month of pregnancy, a structure called the neural tube forms in a developing baby. This tube eventually becomes the brain and spinal cord. In spina bifida, this neural tube does not close completely, leaving a gap in the spine. This can happen anywhere along the spine, but it is most common in the lower back. There are three main types of spina bifida, ranging from mild to severe. The mildest form is called spina bifida occulta, meaning 'hidden' spina bifida. With this type, there is a small gap in one or more of the bones of the spine (vertebrae). However, the spinal cord and nerves usually remain inside the spinal canal and are not damaged. Many people with spina bifida occulta never know they have it, as it often causes no symptoms. A rarer type is meningocele. In this case, the protective membranes (meninges) that surround the spinal cord push out through an opening in the spine, forming a fluid-filled sac on the baby's back. The spinal cord itself is not in this sac, so nerve damage is usually minimal or mild, leading to fewer disabilities. The most severe and common type is myelomeningocele. Here, the spinal canal remains open along several vertebrae, and both the spinal cord and the meninges protrude through the opening, forming a sac on the baby's back. The exposed tissues and nerves are damaged, which can lead to significant physical disabilities, including paralysis and problems with bladder and bowel control.

Symptoms

Symptoms of spina bifida vary greatly depending on the type and severity, especially with myelomeningocele, the most severe form. Mild types like spina bifida occulta often have no noticeable symptoms, while more severe forms can cause physical weakness, problems with bladder and bowel control, and other neurological issues.

Spina bifida occulta often has no symptoms. Sometimes, the only visible sign is on the skin above the defect, such as a small tuft of hair, a dimple, or a birthmark. These skin changes are usually harmless but can sometimes indicate an underlying spinal issue. For meningocele, the main sign is a fluid-filled sac visible on the baby's back. Individuals with meningocele may experience minor functional problems, but severe nerve damage is uncommon because the spinal cord is not directly involved in the sac. Myelomeningocele, the most severe type, typically presents with more significant symptoms due to nerve damage. These can include weakness or complete paralysis of the legs, making walking difficult or impossible. Many individuals also experience problems with bladder and bowel control, requiring ongoing management. Other common symptoms associated with myelomeningocele include hydrocephalus, which is an excess of fluid in the brain, often requiring a surgical shunt. Some babies may also have Chiari malformation type II, where brain tissue extends into the spinal canal, potentially causing breathing or swallowing difficulties. Orthopedic problems like clubfoot, hip dislocation, or a curved spine (scoliosis) are also common. Some children may also experience learning disabilities.

Causes & risk factors

The exact cause of spina bifida is not fully understood, but it is believed to result from a combination of genetic and environmental factors. A major risk factor is a deficiency in folic acid, a B vitamin, before and during early pregnancy, which is crucial for proper neural tube development.

A deficiency in folic acid is the most significant known risk factor for spina bifida. Folic acid is a B vitamin that plays a vital role in the healthy development of the neural tube during the very early stages of pregnancy. When there isn't enough folic acid, the neural tube may not close properly. While not strictly hereditary, genetics do play a role. If you have had one child with a neural tube defect, your risk of having another child with spina bifida is slightly increased. This suggests a genetic predisposition in some families. Certain medications taken during pregnancy can also increase the risk. For example, some anti-seizure medications, such as valproic acid, can interfere with the body's ability to use folic acid effectively. It is important to discuss all medications with your doctor if you are pregnant or planning to become pregnant. Other risk factors include certain health conditions in the mother. Women with poorly controlled diabetes before pregnancy have a higher risk of having a baby with spina bifida. Obesity before pregnancy also increases the risk. Additionally, an increased body temperature (hyperthermia) from fever or using hot tubs or saunas during the very early weeks of pregnancy may contribute to the risk.

How it's diagnosed

Spina bifida can often be diagnosed during pregnancy through routine prenatal screenings, or sometimes after birth. Diagnostic methods include blood tests and imaging scans that look for signs of the condition, allowing for early planning and intervention.

Spina bifida can often be detected during pregnancy through prenatal screening tests. One common test is the maternal serum alpha-fetoprotein (MSAFP) test, usually performed between 16 and 18 weeks of pregnancy. High levels of alpha-fetoprotein (AFP) in the mother's blood can indicate a neural tube defect. If the MSAFP test results are abnormal, or if there are other concerns, a detailed ultrasound can be performed. This imaging test can often detect signs of spina bifida, such as an open spine, or specific brain changes that are associated with the condition. Ultrasound is a non-invasive way to visualize the baby's development. In some cases, if MSAFP levels are high, your doctor may recommend amniocentesis. During this procedure, a small sample of amniotic fluid is taken from the uterus and tested for elevated levels of AFP and acetylcholinesterase, which are markers for neural tube defects. This test provides a more definitive diagnosis. After birth, myelomeningocele is usually obvious due to the visible sac on the baby's back. For milder forms like spina bifida occulta, diagnosis might happen incidentally during imaging for another condition, or if skin signs like a dimple or hair tuft prompt further investigation. Imaging tests such as X-rays, magnetic resonance imaging (MRI), or computed tomography (CT) scans can provide detailed images of the spine and spinal cord to confirm the diagnosis and assess the extent of the defect.

Treatment options

Treatment for spina bifida focuses on managing the condition and its complications, often involving surgery and ongoing supportive care. The specific approach depends on the type and severity of spina bifida, aiming to improve function and quality of life.

Surgery is a primary treatment for spina bifida, especially for meningocele and myelomeningocele. For myelomeningocele, surgery can sometimes be performed before the baby is born (prenatal surgery). This fetal surgery, typically done before 26 weeks of pregnancy, involves operating on the baby in the womb to close the spinal opening. Studies suggest it may reduce the need for a shunt to treat hydrocephalus and improve motor function, though it carries risks for both mother and baby, including preterm birth. More commonly, surgery for myelomeningocele is performed within 72 hours after birth (postnatal surgery). This procedure closes the opening in the baby's back to prevent infection and further nerve damage. For meningocele, surgery is also performed after birth to remove the sac and close the opening. Managing complications is a crucial part of treatment. If hydrocephalus (excess fluid in the brain) develops, a shunt, which is a thin tube, is surgically placed to drain the fluid from the brain to another part of the body, such as the abdomen, where it can be absorbed. This helps relieve pressure on the brain. Lifelong supportive care is often needed. This includes physical therapy and occupational therapy to help individuals develop strength, mobility, and daily living skills. Assistive devices like braces, crutches, or wheelchairs may be necessary depending on the degree of paralysis. Bladder and bowel control problems are common and are managed with medications, special diets, or procedures like catheterization. A multidisciplinary team of specialists, including neurosurgeons, urologists, orthopedists, and rehabilitation therapists, typically provides ongoing care.

Recovery & outlook

The recovery and long-term outlook for individuals with spina bifida vary widely, largely depending on the type and severity of the condition. While some may experience few or no issues, others will require lifelong medical care and support to manage physical and cognitive challenges.

The outlook for individuals with spina bifida depends significantly on the type and severity of the defect. For those with spina bifida occulta, the mildest form, most people experience no symptoms and lead normal lives without needing specific treatment. The condition is often discovered incidentally. Individuals with meningocele generally have a good prognosis after surgical repair. They usually experience mild disabilities, if any, because the spinal cord itself is not damaged. They often achieve full mobility and independence. For myelomeningocele, the most severe type, the outlook involves more significant challenges. Many individuals will experience some degree of paralysis or weakness in their legs, which may require the use of mobility aids such as braces, crutches, or wheelchairs. Bladder and bowel control issues are common and require ongoing management throughout life. Cognitive development can also vary. While some individuals with myelomeningocele may have learning disabilities, many have average intelligence. The presence of hydrocephalus or Chiari malformation can sometimes impact cognitive function. With appropriate medical care, therapy, and support, many individuals with spina bifida lead active and fulfilling lives, pursuing education, careers, and personal interests. Lifelong care from a multidisciplinary team is often essential to address various health needs, including orthopedic issues, skin care, and social-emotional well-being.

When to see a doctor

If you are pregnant and prenatal tests suggest spina bifida, your doctor will guide you on next steps and specialist consultations. After birth, if your baby has a visible sac on their back, or shows signs like leg weakness, or problems with bladder or bowel control, seek immediate medical attention.

During pregnancy, if your prenatal screening tests, such as the MSAFP test, show abnormal results, or if an ultrasound suggests a neural tube defect, your doctor will recommend further diagnostic tests and specialist consultations. This is not an emergency, but it requires prompt follow-up to confirm the diagnosis and discuss potential management options. After birth, if your baby is born with a visible fluid-filled sac on their back, this is a medical emergency. You should seek immediate medical care. This visible sac indicates myelomeningocele or meningocele and requires prompt surgical evaluation to prevent infection and further nerve damage to the exposed spinal cord or membranes. Even without a visible sac, if you notice certain signs on your baby's lower back, such as a deep dimple, a tuft of hair, or a birthmark, you should consult your pediatrician. While often harmless, these can sometimes be subtle indicators of spina bifida occulta or other underlying spinal issues that may require imaging for diagnosis. Additionally, if your newborn shows signs of leg weakness, difficulty moving their legs, or problems with feeding or breathing, consult your pediatrician. These could be signs of a more severe form of spina bifida or related complications like Chiari malformation. For older children or adults with a known history of spina bifida, new or worsening symptoms such as increasing leg weakness, changes in bladder or bowel control, or severe back pain should prompt a visit to a doctor, as these could indicate complications like tethered cord syndrome.

Frequently asked questions

Can spina bifida be prevented?

Yes, in many cases. Taking enough folic acid (a B vitamin) before and during early pregnancy can significantly reduce the risk of spina bifida. Women of childbearing age are advised to take 400 micrograms of folic acid daily. For women who have previously had a child with a neural tube defect, a higher dose of 4,000 micrograms daily is often recommended.

Is spina bifida hereditary?

While genetics play a role, spina bifida is not strictly hereditary in most cases. It's usually a combination of genetic and environmental factors. However, having one child with spina bifida does slightly increase the risk for future pregnancies, suggesting a genetic predisposition in some families.

What is the difference between spina bifida occulta and myelomeningocele?

Spina bifida occulta is the mildest form, where there's a small gap in the spine but usually no opening or nerve damage, often with no symptoms. Myelomeningocele is the most severe type, involving an open spinal canal where the spinal cord and its protective membranes protrude, causing nerve damage and significant disabilities like paralysis.

Do people with spina bifida need wheelchairs?

It depends on the severity of the condition. Individuals with spina bifida occulta or meningocele usually do not need wheelchairs. However, many with myelomeningocele experience leg weakness or paralysis and may use wheelchairs, crutches, or braces for mobility, depending on the extent of nerve damage.

What is hydrocephalus and how is it related to spina bifida?

Hydrocephalus is a buildup of excess fluid in the brain. It is a common complication of myelomeningocele, occurring when the Chiari malformation associated with spina bifida blocks the normal flow of cerebrospinal fluid. It often requires a surgical shunt (a thin tube) for drainage to relieve pressure on the brain.

Can spina bifida be cured?

Spina bifida cannot be cured, but it can be managed. Surgery can close the spinal opening and prevent further damage, and ongoing treatments like physical therapy, occupational therapy, and management of complications help individuals live as independently as possible. Lifelong care is often needed to address various health needs.

Sources

• MedlinePlus — Spina Bifida
• Mayo Clinic — Spina Bifida
• Cochrane Library — Spina Bifida