Colonic atresia is a condition that occurs during embryonic development in which the normal tubular shape of the colon in the fetus is unexpectedly closed. This congenital abnormality may be caused by incomplete development of the colon or the loss of blood flow during its development. Colonic atresia is rare and may occur with the more common small bowel atresia.
The most common cause of non-duodenal intestinal atresia is a vascular accident in utero that leads to decreased intestinal perfusion and ischemia of the respective segment of bowel. This leads to narrowing, or in the most severe cases, complete obliteration of the intestinal lumen. In the case that the superior mesenteric artery, or another major intestinal artery, is occluded, large segments of bowel can be entirely underdeveloped. Classically, the affected area of bowel assumes a spiral configuration and is described to have an "apple peel" like appearance.
Intestinal atresias are often discovered before birth: either during a routine sonogram which shows a dilated intestinal segment due to the blockage, or by the development of polyhydramnios (the build up of too much amniotic fluid in the uterus). These abnormalities are indications that the fetus may have a bowel obstruction which a more detailed ultrasound study can confirm. Some fetuses with bowel obstruction have abnormal chromosomes. An amniocentesis is recommended because it can determine not only the sex of the baby, but whether or not there is a problem with the chromosomes.
Surgery is necessary to open or remove the closed area and re-connect the normal sections of the colon.Fetal and neonatal intestinal atresia treated with using laparotomy after birth. If the area affected is small, the surgeon may be able to remove the damaged portion and join the intestine back together. In instances where the narrowing is longer, or the area is damaged and cannot be used for period of time, a temporary stoma may be placed.