In abdominal wall defects, the intestines and sometimes other organs spill out through a hole in the wall of abdominal cavity.
The 2 main abdominal wall defects are omphalocele and gastroschisis.
Omphalocele
An omphalocele is caused by an abnormal opening (defect) in the middle of the abdominal wall at the bellybutton (umbilicus). The skin, muscle, and fibrous tissue are missing. The intestines and sometimes also the stomach or liver spill out through the opening and are covered by a thin sac. The umbilical cord is in the center of the defect.
Infants who are born with an omphalocele have a high risk of having other birth defects (such as congenital heart disease and kidney defects) or a specific genetic syndrome (such as Down syndrome, trisomy 18, trisomy 13, and Beckwith-Wiedemann syndrome).
Gastroschisis
Gastroschisis is also a defect of the abdominal wall. In gastroschisis, the opening is near the bellybutton (usually to the right) but not directly over it as it is in an omphalocele.
In gastroschisis, intestines spill out through the defect as in an omphalocele but they are not covered by a thin sac.
Before birth, because the intestines are not covered by a sac, they may be damaged by exposure to amniotic fluid, which causes inflammation. The inflammation irritates the intestine, which can result in complications such as problems with movements of the digestive system, scar tissue, and intestinal obstruction.
Infants who are born with gastroschisis have a low risk of having other birth defects other than abnormalities of the digestive tract such as intestinal malrotation and intestinal atresia. Gastroschisis is more common than omphalocele.
(See also Overview of Digestive Tract Birth Defects.)
Diagnosis of Abdominal Wall Defects
Blood tests
Usually prenatal ultrasounds
Doctors may suspect gastroschisis if the level of alpha-fetoprotein (a protein produced by the fetus) in the mother's blood is abnormally high during pregnancy.
Both omphalocele and gastroschisis are usually diagnosed before birth with routine prenatal ultrasounds. If not, the defects are very obvious as soon as the infant is delivered.
Treatment of Abdominal Wall Defects
Surgery
Once the infant is delivered, the exposed intestines are covered with a sterile dressing to keep them moist and protected and the infant is given fluids and antibiotics by vein. A long, thin tube is passed through the nose and placed in the stomach or intestine (nasogastric tube) to drain digestive fluid that collects in the stomach.
Surgery is required to return the intestines and displaced organs to the proper location in the abdomen and close the opening. If possible, surgery to repair the defect is done soon after birth. However, sometimes the skin of the abdominal wall must be stretched for some time before surgery so there is enough of it to cover the opening. If the defect is large, doctors may need to create skin flaps to close it. If a large amount of intestine and other organs is sticking out, it is wrapped in a protective covering (called a silo) and gradually moved back into the abdomen over several days or weeks. When all the intestines are back in the abdomen, the opening is surgically closed.
After surgery, the infant's digestive tract will take several week to start working properly. The infant is fed through a tube or through a vein until the digestive tract is working and sometimes for months afterward. Feedings by mouth will start slowly.
