What is Intestinal Atresia & Stenosis?
Intestinal atresia and stenosis is a fetal abnormality where the intestine is narrowed, blocked or disconnected. This prevents the baby from absorbing nutrition properly. It occurs in the small or large intestine and has various forms. Atresia refers to a complete blockage or obstruction. Stenosis refers to partial obstruction or a narrowing of the intestine. They are often referred to as "bowel obstructions." All forms require surgical treatment immediately in the days after birth to correct the condition and allow the baby to receive nutrition. Sanford Fetal Care Center specialists provide intestinal atresia diagnosis and intestinal atresia treatment and coordinate care with our Neonatal Intensive Care Units.
Different Types of Atresia
The intestines are divided into two sections: small intestine and large intestine (also called the colon or large bowel). The small intestine is where most nutrition is absorbed. It is divided into three parts: duodenum (the first section after the stomach), the jejunum (where much of the nutrition absorption takes place) and the ileum, the longest section that connects to the large intestine. The empty space in the intestine is called the lumen.
Obstructions are named after the location where they occur:
- Pyloric – a narrowing or obstruction where the stomach joins the small intestine.
- Duodenal – obstruction in the duodenum. Half of babies with this type are born prematurely, up to 40% have Down's syndrome, while 50 – 75% will have other anomalies, usually of the digestive system, heart or kidneys. Duodenal obstructions occur in 1 out of 2,500 live births.
- Jejunoileal – occurs in the jejunum and/or the ileum. Jejunoileal includes several types of obstruction and may include areas where the intestine is missing, or has multiple obstructions. Cystic fibrosis is often an associated disorder. Babies with jejunoileal obstructions should be screened for this genetic disorder.
- Colonic – seen more rarely, obstructions occur in the large intestine and account for less than 15% of cases. It may be in conjunction with small intestine atresia, Hirschsprung's disease or Gastroschisis.
What Causes Intestinal Atresia?
Intestinal atresia appears to run in families, though the exact genetic cause is unknown. It is believed to occur during fetal development due to an inadequate supply of blood flow to the intestines while they are developing early in the pregnancy. Intestinal atresia occurs in 1 out of 1,500 live births and affects boys and girls equally.
How is Intestinal Atresia Diagnosed?
Intestinal atresia and stenosis is often discovered during routine prenatal ultrasounds, or if a mother is diagnosed with polyhydramnios (too much amniotic fluid in the uterus). The extra fluid builds up because it is not being processed through the baby's intestines. An amniocentesis will be recommended to screen for chromosomal disorders and a fetal echocardiogram may be done to check the fetus's heart.
Within hours to a day after birth, babies with intestinal atresia show signs of not tolerating feedings, vomiting, stomach distension and lack of bowel movements. An x-ray of the stomach can often confirm the obstruction. Additionally, your physician may order an Upper GI test with barium (a contrast fluid) that your baby will swallow. The barium coats the lining of the intestines and shows up on the x-ray. A Lower GI may also be done, with barium given as an enema. Ultrasound may also be done to identify blood flow within the intestinal walls and obstructions.
What Does it Mean for My Baby?
All babies with intestinal obstructions require surgery to repair the intestine. Without it, intestinal atresia is life threatening as the child cannot receive nutrition to survive. Following surgery, most babies do quite well. The outcome will depend on how much of the intestine remains and how well your baby is able to absorb nutrition and gain weight. Long-term follow up is usually required.
If My Baby is Diagnosed with Intestinal Atresia, What Happens Next?
If diagnosed during pregnancy, your Fetal Care team will counsel you on what to expect after delivery and will manage any symptoms of polyhydramnios you may have. Treatment on the fetus is not done until the baby is born.
How is Intestinal Atresia Treated?
After your baby is born, your Fetal Care team will make sure she is stabilized before surgery takes place. Your baby will undergo ultrasound and/or x-rays and a nasogastric tube will be inserted through her nose into the stomach. The extra stomach contents, gas and pressure will be relieved before the baby goes to surgery. IV fluids will also be given to your baby.
During surgery, the surgeon will determine the extent of the atresia and do everything possible to spare healthy tissue. Blockages will be removed and the intestine connected so that continuity is attained. In some cases, the intestine may need extra time to heal and the surgeon may create a stoma – an opening in the abdominal wall where the intestine is brought up to the surface. This is where the baby's feces will be expelled (instead of the anus) into a colostomy bag for a temporary period of time. If a stoma is required, a second surgery will be needed when it's time to reconnect the intestines.
After surgery, your baby will be cared for in the Neonatal Intensive Care Unit, where he will be carefully monitored. Specialized nutritional IV or tube feedings will be continued until your baby can tolerate regular feedings. We encourage mothers to pump and store breast milk during this time. The length of hospital stay is generally several weeks, but can be longer. It depends on how well your baby does after surgery and when they are able to take all feedings by mouth, gain weight and have normal bowel functioning. The primary factor that impacts recovery is how much of the intestine remains after surgery and whether or not complications develop.
Many babies do very well, while some do develop complications. These can include risk of intestinal content leaking around the suture line following surgery, which may cause infection and require additional surgery; malabsorption syndromes; functional obstruction due to scar tissue or paralyzed segments of intestine, and short bowel syndrome. Short bowel syndrome requires long-term specialized feedings and, in some cases, can be treated with an intestinal transplant. Long-term follow up care is normal for most babies with intestinal atresia to monitor their development and nutritional intake.
Where Can I Find More Information and Support?
Talk to your Sanford Fetal Care team to learn more about intestinal atresia and stenosis. Additionally, our genetic counselors are available to discuss genetic concerns about this condition.