Encephalocele (en-SEF-ah-lo-SEEL) is a type of neural tube defect (NTD) that occurs very early in fetal life where the embryo's cells that form the skull do not come together to close over the brain. The result is a defect in the bones of the skull, causing brain tissue to protrude or bulge from the skull. The protruding tissue may be located on any part of the head but is usually in the middle back of the head (midline occipital area). There may be meninges, brain tissue, parts of the ventricles and bone that protrude from the skull. Encephaloceles are typically diagnosed by prenatal ultrasound. Encephaloceles located on the front of the skull are more likely not to contain brain tissue and have better outcomes than those at the back of the head.
At least half of all survivors of encephaloceles have significant cognitive deficits. The involved brain structures will determine the type of deficit, but significant motor and learning deficits are common.
The cause of an encephalocele is not known but it is probably a combination of factors such as maternal nutrition, a genetic predisposition, and exposure to toxins or infections very early in fetal life. Neural tube defects appear to be associated with maternal lack of folic acid, and supplementing the diets of all women of childbearing age with folic acid is decreasing the rate of these disorders. Encephaloceles occur at a rate of 1 in 5,000 live births and are often associated with stillbirth before 20 weeks gestation. Only 20% of babies with encephaloceles are born alive, and only 1/2 of those survive. Our program has been tracking encephalocele among live births in select counties since 2005 and are gradually expanding statewide.
- Using data from births to Hennepin and Ramsey county residents between 2007-2011, we found that fewer than 1 baby was born with encephalocele per 10,000 births.
- Using this data, we estimate about about 2 babies are born with encephalocele every year in Minnesota.
Parental education and support are essential, and local, regional and national organizations may be very helpful.