An encephalocele (in-sef-a-luh-seal) is a rare disorder in which the bones of the skull do not close completely, creating a gap through which cerebral spinal fluid, brain tissue and the membrane that covers the brain (the meninges) 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 (term used to describe a developing baby to the eighth week after conception) that becomes the brain, spinal cord, and the bones surrounding each.
A meningocele is an encephalocele that contains only the meninges and cerebral spinal fluid. These type of defects have a much better prognosis than those where brain tissue also protrudes into the sac.
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 or the back of the skull. The 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 typically it is an obvious malformation.
Encephaloceles are frequently associated with other cranial (head, skull, or brain) and/or facial abnormalities. In the United States, encephaloceles occur in approximately 1-4 per 10,000 live births. The presence of an encephalocele is associated with an increased incidence of death in utero. It is estimated that only half survive to birth. It is seen more commonly in females than males. 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:
Most encephaloceles are diagnosed on routine ultrasound. The alpha-fetoprotein levels are not typically elevated with this defect because the defect is covered by skin. Once an encephalocele is diagnosed, a thorough examination of the baby is recommended to look for other anomalies. 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 habitus, the surrounding amniotic fluid, and the position of the fetus. MRI is a non-invasive 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. Your obstetrician will most likely refer you to a specialist that handles high-risk pregnancies. These doctors are called perinatologists.
How does an encephalocele affect my baby?
The prognosis for an encephalocele depends on the size of the defects and the amount of brain tissue that has herniated out into the sac, the location of the defect and 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 impacts 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 these babies have a chromosomal abnormality and approximately 75 percent of babies who survive will have some degree of mental deficit.
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 (uncoordinated voluntary movements), developmental delays, vision problems, growth retardation and seizures. It is recommended that these babies be delivered at a tertiary care center (a hospital that is capable of caring for critically ill infants) to facilitate coordination of services for the newborn.
How does an encephalocele affect my pregnancy?
A thorough search for associated anomalies should be done with a targeted ultrasound performed by a perinatologist. Accurate diagnosis of the defect is essential to provide appropriate prognosis and genetic counseling. An MRI may also be recommended to get a more accurate and detailed picture of the defect and any associated anomalies.
Because of the risk of chromosomal abnormalities, an amniocentesis will be offered.
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. A genetic consultation is recommended for any family with a baby affected with an encephalocele.
If the encephalocele is large, the baby's head may be too big to fit through the birth canal and a Caesarean section may be required to deliver the 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 very likely to die before birth. Approximately 21 percent, or one in five, are born alive. Of those born alive, only half will survive. Fetuses with an front-type encephalocele are much more likely to survive than those with 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 your 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.
How is an encephalocele treated?
Surgery will be needed to place the protruding tissues, brain and cerebral spinal fluid back into the skull and close the opening. The baby is normally given at least a few days and up to a few months to adjust to life outside the womb before surgery is attempted. Most surgical repairs are done between birth to 4 months of age. The timing of the surgery depends on the size, location, associated anomalies and whether the defect is skin covered. Surgery must be performed more quickly if there is no skin covering over the defect or if there is hemorrhage, airway obstruction or impairment of vision. When surgical correction is not urgent, the baby is evaluated for other problems before surgery.
Sometimes, if the defect is large and/or other anomalies are found, the recommendation for treatment may be to provide palliative care for the baby. This means we support the baby with food, comfort and oxygen as needed, but no surgical procedures are done and the baby's life is not extended with any type of life support machinery. These babies can even go home with hospice support if that is desired. We will have open discussions about your desires for your baby and family to help guide your decisions for treatment.
What about after surgery?
After surgery, recovery will vary depending on the age of the baby, how extensive of a repair was required and surgical time. Your baby will likely need assistance with breathing for a time. An endotracheal tube is passed between the two vocal cords and into the trachea or windpipe. This tube is attached to a ventilator, which can deliver oxygen and help the baby's lungs to inflate.
He or she also will have IV lines. If the baby is a newborn, 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 do a needle stick. The blood pressure can also be monitored via an arterial line. Fluids and medication can be administered through this line as well.
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 solutions called TPN, or total parenteral nutrition, if the baby is not able to eat. Two types of solutions are given. 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.
The baby also may have a peripheral IV. These lines can be in the arms, hands, feet, or scalp.
Each procedure will be explained 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 assist in answering 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. You can bring in pictures, small toys, booties and blankets for your baby while he or she is in the NICU.
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. The baby's respiratory status or breathing also must be stable. If it is necessary to send your baby home with equipment, you will be trained on how to care for the baby and the equipment, as well as emergency procedures. These babies often require follow-up with a variety of specialists once they go home.
If you have decided against aggressive therapy, the 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, syndromes or if brain tissue protrudes into the sac. Approximately 75 percent of these infants who do survive have varying degrees of mental deficit
1 year ago