Intestinal Atresia

What happens in intestinal atresia

During development in the womb, the intestine forms as a tube. In atresia, a segment fails to form a continuous channel or loses its blood supply, leaving a closed-off section or a gap. Above the blockage, the intestine fills with fluid and swells; below it, the bowel is small and unused.

Types

Some jejunal atresias take an "apple peel" or "Christmas tree" form, where a long length of bowel spirals around a single blood vessel. This type is more likely to result in short bowel.

Causes

• Duodenal atresia: thought to result from failure of the duodenum to reopen after a normal stage of development when it is temporarily solid.
• Jejunoileal atresia: usually caused by an interruption of blood flow to part of the developing intestine, from twisting (volvulus), compression or a vascular event. Maternal smoking and some vasoconstricting drugs in pregnancy have been associated with higher risk.
• Associated conditions: Down syndrome with duodenal atresia; cystic fibrosis with meconium ileus and some ileal atresias.

Signs and symptoms

• vomiting, often green (bile-stained), starting within hours to 2 days of birth; earlier and less distension with higher blockages
• abdominal swelling, more marked with lower blockages
• no meconium, or only small amounts of pale mucus
• poor feeding, dehydration and jaundice

Prenatally, polyhydramnios (too much amniotic fluid) may occur because the baby cannot swallow and absorb fluid normally. Dilated bowel loops or the "double bubble" may be seen on ultrasound.

Diagnosis

• Prenatal ultrasound may raise suspicion.
• Abdominal X-ray after birth shows dilated bowel loops and absence of gas beyond the blockage. A "double bubble" indicates duodenal atresia.
• Contrast studies: an upper GI study or contrast enema to locate the blockage, rule out malrotation and look for other causes such as Hirschsprung disease or meconium ileus.
• Further tests for associated conditions: heart ultrasound, chromosome testing, and cystic fibrosis testing for ileal atresia.

Treatment

Before surgery

• stop feeding and give IV fluids and nutrition
• place a tube through the nose or mouth into the stomach to drain fluid and reduce vomiting
• correct dehydration and electrolyte problems

Surgery

Surgery is done within the first days of life. The surgeon removes the closed segment and joins the healthy ends of the intestine (anastomosis). For duodenal atresia, the bowel above and below the blockage is joined directly (duodenoduodenostomy). Multiple atresias are repaired at the same operation. Sometimes a temporary stoma is created.

After surgery

• IV nutrition until the bowel starts working, which can take days to weeks
• gradual introduction of breast milk or formula
• monitoring for leaks, blockages and growth

Complications

• slow return of bowel function
• leak or narrowing at the join
• adhesions causing later blockage
• short bowel syndrome if a large length of intestine is missing or removed, requiring long-term nutrition support; see short bowel syndrome

Outlook

Survival is above 90% for most types in modern pediatric surgery centers. Outcomes are mainly affected by prematurity, associated heart or chromosomal conditions, and how much bowel remains. Most children grow and develop normally after recovery.

Frequently asked questions

What are the signs of intestinal atresia in a newborn?

The main signs are vomiting, often green, in the first 1 to 2 days of life, a swollen belly, and passing little or no meconium. Babies may feed poorly and become dehydrated. Green vomiting in a newborn always needs emergency assessment.

What causes intestinal atresia?

Duodenal atresia is thought to result from the duodenum not reopening during development, and is often linked to Down syndrome. Jejunal and ileal atresias usually result from loss of blood supply to part of the intestine in the womb. Nothing parents did typically causes it.

Can intestinal atresia be detected before birth?

Often, yes. Prenatal ultrasound may show excess amniotic fluid, dilated bowel loops or a double bubble. Not all cases are detected. When suspected, delivery at a hospital with neonatal surgery is recommended.

What is the survival rate for intestinal atresia?

With surgery at a specialist center, survival is above 90% for most babies. Outcomes depend on prematurity, other birth defects and whether enough intestine remains for normal nutrition.