Pyloric atresia involves an obstruction at the pylorus, which is the passage linking the stomach and the first portion of the small intestine (duodenum).
This is quite rare, and tends to run in families. Children vomit stomach contents, and due to the accumulation of intestinal contents and gas, develop a swollen (distended) upper abdomen. Abdominal X-rays reveal an air-filled stomach but no air in the remaining intestinal tract.
The duodenum is the first portion of the small intestine that receives contents emptied from the stomach.
Duodenal atresia occurs in one out of every 2,500 live births. Half of the infants with this condition are born prematurely and approximately two-thirds have associated abnormalities of the heart, genitourinary or intestinal tract. Nearly 40 percent have Down syndrome. Infants with duodenal atresia usually vomit within hours after birth, and may develop a distended abdomen. Abdominal X-rays show a large dilated stomach and duodenum without gas in the remaining intestinal tract.
Duodenal Atresia - Example 1
Duodenal Atresia - Example 2
Jejunoileal atresia involves an obstruction of the middle region (jejunum) or lower region (ileum) of the small intestine.
The segment of intestine just before the obstruction becomes massively enlarged (dilated), thus hindering its ability to absorb nutrients and propel its contents through the digestive tract. In 10 percent to 15 percent of infants with jejunoileal atresia, part of the intestine dies during fetal development. A significant percentage of infants with this condition also has abnormalities of intestinal rotation and fixation.
Cystic fibrosis is also an associated disorder and may seriously complicate the management of jejunoileal atresia. Infants with jejunoileal atresia should be screened for cystic fibrosis.
Four subtypes of jejunoileal atresia
Types of Jejunoileal Atresia
- Atresia type I: The blockage is created by a membrane (web) present on the inner aspect of the intestine. The intestine usually develops to a normal length.
- Atresia type II: The dilated intestine terminates as a blind end. It is connected to a smaller caliber segment of the intestine by a fibrous scar. The intestine develops to a normal length.
- Atresia types IIIa and IIIb: The blind ends of intestine are separated by a defect in the intestinal blood supply. This often leads to a significantly shortened intestinal length that may result in long-term nutritional deficiencies or the short gut syndrome.
- Atresia type IV: Multiple regions of obstruction exist. This may result in a very short length of useful intestine.
Infants with jejunoileal atresia, regardless of the subtype, usually vomit green bile within the first 24 hours of life. However, those with obstructions farther down in the intestine may not vomit until two to three days later. Infants often develop a swollen (distended) abdomen and may not have a bowel movement (as is normally expected) during the first day of life. Given the age of the patient and the symptoms, an abdominal X-ray is usually sufficient to establish a diagnosis.
This rare form of intestinal atresia accounts for less than 15% of all intestinal atresias. The bowel becomes massively enlarged (dilated), and patients develop signs and symptoms similar to those associated with jejunoileal atresia. Colonic atresia may occur in conjunction with small bowel atresia, Hirschsprung's disease or gastroschisis. The diagnosis is confirmed by an abdominal X-ray along with an X-ray contrast enema.