Many babies who have meconium ileus have cystic fibrosis. They are often diagnosed while still in the womb with ultrasound or other tests and given a sweat test to find out if they have CF.
Meconium ileus is defined as neonatal bowel obstruction due to inspissated meconium obstructing the terminal ileum. It can lead to complications such as volvulus and atresia.
Symptoms
Newborns typically pass meconium within the first 12 to 24 hours. Newborns with meconium ileus do not pass this stool and have signs of intestinal blockage, including vomiting that may be bilious. They also have abdominal distention and may have enlarged loops of the small bowel that are visible through their skin or can be felt by doctors through their abdomen.
Doctors usually suspect meconium ileus in babies with a family history of cystic fibrosis and when routine newborn screening tests are positive for CF. They can often see signs of the condition in a prenatal ultrasound and sometimes can even diagnose it before the baby is born. In these cases, they make a plan for the birth and post-delivery care of the baby based on this diagnosis.
After birth, if the diagnosis is meconium ileus, the doctor will give the baby a water-soluble contrast enema under fluoroscopy to make sure nothing is blocking the intestines. If the X-ray reveals a blockage, the baby will receive an immediate surgery called a bowel resection. The prognosis is good for these surgeries.
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In the more complicated form of meconium ileus, abnormally tenacious meconium obstructs the terminal ileum. This forms a mass of chyme in the terminal ileum that can lead to a complication called meconium peritonitis, or more severe obstruction, including volvulus, atresia, necrosis, bowel wall thickening, and even perforation and pseudocyst formation. This type of meconium ileus occurs in 9-33% of neonatal cases and is the first clinical sign of cystic fibrosis in many patients.
Babies who have a simple meconium ileus are treated with fluids and pancreatic enzyme replacement therapy (PERT) until they are ready to start oral feedings. They will begin with a low volume, half strength, and predigested formula, then gradually increase the amount of liquid and the strength of the feeds as they heal. Those with complicated meconium ileus who undergo a surgical course will continue to receive diluted and predigested formula through a tube until they are able to tolerate oral feedings. Babies with this condition experience excessive sweat and intestinal sodium losses after the surgery, so it is important to monitor for dehydration and electrolyte disturbances.
Diagnosis
Newborns typically pass meconium within the first 12 to 24 hours. If they don’t and have other symptoms of intestinal blockage, including vomiting, abdominal distention or a swollen abdomen, doctors suspect meconium ileus. They might also suspect it if there’s a family history of cystic fibrosis or the baby tests positive for the condition on routine newborn screening. Doctors sometimes can see signs of meconium ileus on a prenatal ultrasound, but they usually don’t make the diagnosis until after birth.
Meconium ileus is the most common cause of small-bowel obstruction in neonatal infants, accounting for 9-33% of cases. It happens in both CF patients and non-CF patients, and occurs in a simple or complicated form. The simple form results from abnormally thick, tenacious meconium, which obstructs the terminal ileum. Complicated meconium ileus is more serious, causing occlusion of the proximal small bowel and dilatation of the intestines. This may lead to complications such as volvulus, gangrene or perforation.
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A diagnosis is made based on clinical presentation and X-rays. In most cases, the meconium plug is dislodged with digital stimulation of the anus and rectum. The obstructed segment of the colon is usually smaller than normal, and it will return to its normal size with passage of the meconium.
In severe cases, a baby with meconium ileus might need to be hospitalized. A doctor might try to break up the blockage with medicine given through an enema. If the blockage doesn’t clear up, a surgeon might need to remove part of the baby’s small intestine.
During surgery, the baby will be fed through an IV (intravenous) line in the vein or a tube — called a nasogastric tube — that’s passed through the nose into the stomach to help remove air and fluid from the intestine. If a bowel resection is needed, the child will probably have a general anesthesia to ensure her safety and comfort. The surgery usually takes place about a week after birth. The child might need antibiotics for a few weeks afterward to prevent infections. This is why it’s important for people with CF to get genetic screening before getting pregnant.
Treatment
The condition occurs when a baby’s first stool, called meconium, is not passed within the usual few days or hours after birth. The sticky substance is the product of a woman’s uterus during pregnancy and during childbirth, and it contains bacteria needed to break down food and other substances in the digestive tract. When meconium isn’t passed, the intestine can become blocked, resulting in a dangerous condition called meconium ileus.
Newborns who have meconium ileus require intensive care, as they are at risk for serious complications. Symptoms include a lack of bowel movements, abdominal distention and refusal to feed. The condition is usually diagnosed through anal stimulation and x-rays, but can also be confirmed with a diagnostic contrast enema.
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If the meconium is causing a blockage, a healthcare provider will inject a solution into your baby’s rectum using a medical imaging procedure called fluoroscopy that allows them to see real-time video of the intestines in action. The solution breaks down the thickened meconium, which then passes through your baby’s intestines. If the problem is more complex, such as a hole in the intestine (perforation), surgeons may choose to bypass the enema and go straight to surgery to remove the meconium and fix any other problems.
Babies who undergo meconium ileus surgery will often be hospitalized for several days until they are able to eat by mouth. They will be given diluted, pre-digested infant formula through a tube until they are ready to start feeding themselves. They will also be given medication to prevent infection, as they will likely have a temporary stoma or ileostomy through which food will pass.
Because meconium ileus is linked to cystic fibrosis, babies who have it are screened for CF at the time of their initial evaluation. A blood test and sweat sample are also usually taken to confirm CF. Pregnant women who have a family history of the disease should consider having cystic fibrosis carrier screening before getting pregnant, so they can know their risk for passing it on to their babies. CF testing can also be done before a baby is born, as it can help healthcare providers prepare for any potential complications during childbirth.
Prevention
Meconium Ileus happens when a newborn’s first stool (feces) gets stuck in the last part of their small intestine (ileum). Newborns produce sticky substances called meconium that are meant to pass through the ileocecal valve. If the meconium gets stuck, it can cause a blockage in the intestine. Most babies with meconium ileus have cystic fibrosis (CF). This disease makes the fluids and mucus in the body thicker, which increases the chance that meconium will get stuck.
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Babies born with meconium ileus usually need to go to the hospital right away. The doctors at Seattle Children’s will do a thorough exam. They may press on the baby’s belly and feel a loop of the small intestine that is filled with meconium. They will also look at X-rays of the baby’s stomach and intestines. The X-rays will show enlarged loops of the small intestine that are filled with meconium. They might also see soap bubbles in the intestine that appear when air mixes with meconium.
Babies with meconium ileus can be helped by surgery to remove the meconium from the intestine. In some cases, the doctor will try an enema before surgery. However, babies with more complex problems — like a hole in the intestine (perforation) — need to have surgery right away. Most babies with meconium ileus recover well after surgery to remove the meconium and other intestinal problems. They may need a feeding tube in their tummy (feeding tube) or in their nose (needle tube). Babies who have meconium ileus because of CF will need lifelong medical management for CF.
