What is an encephalocele?
An encephalocele (in-sef-a-luh-seal) is a rare disorder in which the bones of the skull do not close completely. This creates a gap through which cerebral spinal fluid, brain tissue and the meninges (the membrane that covers the brain) can protrude into a sac-like formation.
An encephalocele (sometimes called a cephalocele or meningoencephalocele) is classified as a neural tube defect. The neural tube is the tissue of an embryo that becomes the brain, spinal cord and bones surrounding each. (Embryo is term used to describe a developing baby to the eighth week after conception).
A meningocele is an encephalocele that contains only the meninges and cerebral spinal fluid. These types of defects have a much better prognosis than those in which brain tissue also protrudes into the sac.
Where do encephaloceles occur within the skull?
The most common locations for an encephalocele include:
- The midline of the upper part of the skull
- The area between the forehead and the nose
- The back of the skull
Encephaloceles at the back of the skull are more likely to be associated with neurologic problems. Occasionally, an encephalocele may go undetected because of its size and location, but usually, it is an obvious malformation.
Can encephaloceles occur with other abnormalities?
Encephaloceles are frequently associated with other cranial (head, skull, or brain) and/or facial abnormalities.
How common are encephaloceles?
In the United States, encephaloceles occur in approximately 1 to 4 per 10,000 live births. The presence of an encephalocele is associated with an increased incidence of death in utero. Experts estimate that only half of the children with encephaloceles survive to birth. They are seen more commonly in females than males.
What causes encephaloceles?
We do not know the cause of an encephalocele, but we do know it is not due to anything the mother did or did not do during pregnancy.
Prenatal diagnosis of an encephalocele
Doctors diagnose most encephaloceles during a routine ultrasound. An alpha-fetoprotein blood test usually does not help to diagnose encephaloceles. This is because AFP levels are not typically elevated with this defect because the defect is covered by skin.
If your child is diagnosed with encephalocele, we recommend a thorough examination of him or her to look for other anomalies.
Are there other tests to help with diagnosis?
Recently, some research suggests the fetal MRI may give a more detailed picture of the central nervous system. Ultrasound imaging can be limited by the mother's body, the surrounding amniotic fluid and the position of the fetus. MRI is a noninvasive diagnostic test that produces better images of soft tissue, and bone or dense tissue does not interfere with the image as it can with ultrasound.
The best assessment is done when the fetus is still, which is the challenge of fetal MRI. If your child is diagnosed with encephalocele, your doctor will likely refer you to a maternal-fetal medicine specialist (a specialist that handles high-risk pregnancies).
How does an encephalocele affect my baby?
The prognosis for an encephalocele depends on a number of things, including:
- The size of the defect(s) and the amount of brain tissue that has pushed out into the sac
- The location of the defect
- The presence of other birth defects or anomalies
Encephaloceles may be associated with brain malformations that can have an effect on the prognosis.
The location of the encephalocele greatly affects the prognosis. Those located in the front have a 100 percent survival rate, while those located in the back have a 55 percent survival rate. In the United States, the most common type of encephalocele is in the back, while in Southeast Asia a frontal type is more common.
Approximately 13 to 44 percent of babies with encephaloceles have a chromosomal abnormality, and approximately 75 percent of babies who survive will have some degree of mental deficit.
What are the most common abnormalities of children with encephaloceles?
The most commonly associated abnormalities and symptoms of survivors include:
- Hydrocephalus (abnormal accumulation of fluid in the brain)
- Spastic quadriplegia (paralysis of the arms and legs)
- Microcephaly (smaller than average head size)
- Ataxia (poor coordination and unsteadiness)
- Developmental delays
- Vision problems
- Growth retardation
Will I have to delivery my baby at a special hospital?
If your baby has been diagnosed with encephalocele, we recommend that you deliver him or her at a tertiary care center (a hospital that is capable of caring for critically ill infants).
How does an encephalocele affect my pregnancy?
If your doctor suspects your baby has an encephalocele, you likely will undergo some tests.
- Targeted ultrasound: Your maternal-fetal medicine specialist likely will perform a targeted ultrasound to do a thorough search for associated anomalies. Accurate diagnosis of the defect is essential to provide appropriate prognosis and genetic counseling.
- MRI: Your doctor may also recommend an MRI to get a more accurate and detailed picture of the defect and any associated anomalies.
- Amniocentesis: Because of the risk of chromosomal abnormalities, your doctor likely will offer an amniocentesis to check for any chromosomal involvement.
Risks during pregnancy
If your baby has been diagnosed with an encephalocele, you are at greater risk for some complications and problems during pregnancy, including:
- Possible cesarean section
If the encephalocele is large, your baby's head may be too big to fit through the birth canal. In this case, you may have to have a cesarean section to deliver your baby.
However, minimizing maternal risk is most important when the encephalocele is large and there are associated anomalies because of the poor prognosis for the baby.
Fetuses with an encephalocele are likely to die before birth. Approximately 21 percent, or 1 in 5, are born alive. Of those born alive, only 50 percent will survive.
Fetuses with a front-type encephalocele are much more likely to survive than those who have an encephalocele on the back of the head. The absence of brain tissue within the sac is the single most favorable prognostic indicator. Presence of associated malformations is another indicator of prognosis.
Once an accurate diagnosis of the defect and any associated anomalies has been made, you will be counseled regarding your baby's probable outcome or prognosis. If the prognosis is poor, but you desire is to continue the pregnancy, palliative care may be offered as an option of care for your baby when he or she is born.
Will my future pregnancies be affected?
With an isolated encephalocele, there is no increased risk for future pregnancies to be affected in the same way. However, if the encephalocele is part of a syndrome, this may not be true. A syndrome would have associated anomalies along with the encephalocele. We recommend a genetic consultation for any family with a baby affected by an encephalocele.
How do you treat an encephalocele?
Your child will need surgery to place the protruding tissues, brain and cerebral spinal fluid back into the skull and close the opening. However, we don’t usually do surgery right after birth. Instead, we allow your baby anywhere from a few days to a few months to adjust to life outside the womb before we attempt surgery.
Most surgical repairs are done between birth and 4 months of age. The timing of the surgery depends on the size and location of the encephalocele, associated anomalies, and whether the defect is skin-covered. We must perform surgery more quickly if there is:
- No skin covering over the defect
- Airway obstruction
- Vision impairment
When surgical correction is not urgent, your baby will be evaluated for other problems before surgery is performed.
Sometimes, if the defect is large and/or other anomalies are found, we may recommend palliative care for your baby. This means we support the baby with food, comfort and oxygen as needed, but we do not perform surgery or extend your baby’s life with any type of life-support machinery. Hospice is also an option.
We will have open discussions about your desires for your baby and family to help guide your decisions for treatment.
What happens after surgery?
After surgery, recovery will vary depending on the age of your baby, how extensive of a repair was required and surgical time.
Your baby likely will need assistance with breathing for a while. During surgery, we will pass an endotracheal tube between the two vocal cords and into the trachea or windpipe. This tube is attached to a ventilator, which can deliver oxygen and help your baby's lungs inflate.
Your baby will also have IV lines. If your baby is a newborn at the time of surgery, these lines may be placed in the umbilical cord. The umbilical cord normally has two arteries and one vein. The arterial line provides access for blood to be drawn for lab work rather than having to perform a needle stick. We can also monitor blood pressure via an arterial line and administer fluids and medication.
The vein in the umbilical cord will also be threaded with a thin flexible catheter or tubing. Through this line, we can give nourishment in the form of an IV solution called TPN, or total parenteral nutrition, if your baby is not able to eat. TPN includes two types of solutions. One contains all the calories, vitamins and minerals necessary for normal daily intake. This is a yellow solution. Another type of nourishment provided through this line is fats. This solution appears white and milky.
Your baby may also have a peripheral IV. These lines can be in the arms, hands, feet or scalp.
We will explain each procedure to you as it is done unless it is an emergency situation.
Will I be able to help care for my baby after surgery?
Yes. Please ask your baby's nurse about ways to interact with and care for your baby.
If you had planned to breastfeed your baby, you can begin to pump and freeze your breast milk while you are still in the hospital. A lactation consultant can answer your questions. Your milk will be frozen and stored in the Neonatal Intensive Care Unit until your baby is ready for it. The NICU has breast pumps and private rooms available to you when you are visiting.
When can my baby go home?
Your baby will go home when he or she has recovered from surgery and is able to take in enough food to maintain and gain weight. Your baby's respiratory status or breathing also must be stable. If it is necessary to send your baby home with equipment, we will train you how to care for your baby and the equipment, and you will be trained in emergency procedures. Babies with encephalocele often require follow-up with a variety of specialists once they go home.
If you have decided against aggressive therapy, your baby can go home with you with support from a hospice service.
What is my baby's long-term prognosis?
Babies with a frontal encephalocele, no associated syndrome or defects, and no brain tissue herniating into the sac have a good chance of survival.
Babies with an encephalocele at the back of the head have a 55 percent survival rate. Long-term prognosis for survival becomes less likely if there are other complications, such as associated defects or syndromes or if brain tissue protrudes into the sac. Approximately 75 percent of these infants who do survive have varying degrees of mental deficit.
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