Spina Bifida

What Is It?

Spina bifida is one of a group of disorders called neural-tube defects — malformations of the brain, spinal cord or their coverings. Spina bifida occurs when a fetus's developing spinal column does not close properly in the first 28 days following fertilization. The disorder can take one of three forms:

• Spina bifida occulta — The spinal column is not completely closed. This may not cause any symptoms.
• Meningocele — Part of covering of the spinal cord called the meninges may protrude through an opening in the back.
• Myelomeningocele — A portion of the spinal cord itself protrudes through an opening in the back.

Meningoceles and myelomeningoceles may appear as saclike structures on an infant's back at birth. When most people refer to spina bifida, they are referring to the most severe form, myelomeningocele, which occurs in about one in 1,000 births.

Symptoms

The symptoms of spinal bifida can range from mild or severe depending on the severity of the condition itself. In myelomeningocele, the child may have muscle weakness or paralysis below the level of the incompletely closed spinal column, because nerves traveling to the rest of the body from the spinal cord do not function properly. Loss of sensation and an inability to control bladder or bowel function are common. Additionally, cerebrospinal fluid may build up in the brain, leading to a condition called hydrocephalus, which is common in children with myelomeningocele. If left untreated, hydrocephalus can cause brain damage, blindness or seizures.

In addition to physical problems, spina bifida can produce learning problems, including difficulty with the following:

• Paying attention and expressing or understanding spoken language
• Reading and mathematical concepts
• Organizing or sequencing information

Other conditions that may occur more often in those with spina bifida include latex allergy (perhaps related to the multiple surgeries required early in life), tendonitis, obesity, skin problems, depression and gastrointestinal disorders.

Diagnosis

Spina bifida most often is diagnosed at birth when a sac on the baby's spine is seen. Spina bifida sometimes can be suspected during pregnancy as a result of a test called alpha-fetoprotein, or AFP. Because a number of factors can influence the results of an AFP test, a high level does not establish the diagnosis by itself. If the AFP level is elevated, the test is usually repeated, and if the level is still abnormal, further diagnostic studies such as ultrasound may be done.