Meconium ileus: definition, causes, treatments

Meconium ileus (MI) is a blockage of stool in the small intestine that occurs shortly after birth. It is often a first sign of cystic fibrosis (CF).When myocardial infarction occurs, a baby’s first stool does not pass as it normally should. The stools may also be thicker, stickier, and drier than usual.

Myocardial infarction is a serious condition in newborns that requires urgent treatment to prevent complications. Keep reading to learn more about the symptoms and causes of myocardial infarction, how doctors diagnose the condition, and treatment options.

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Myocardial infarction is a condition in which the first stool produced by a baby, called meconium, cannot pass as usual due to a blockage in the small intestine.

Meconium is made up of amniotic fluid, mucus, fine hairs, bile, and loose skin cells. It usually appears green, brown or yellow.

Healthy babies produce meconium within 24 to 48 hours after birth. However, these stools sometimes have a slimy consistency that makes it difficult for your baby to pass. If your baby does not pass meconium within 48 hours, it could be a sign that your baby has an MI.

MI requires prompt medical attention. If left untreated, it can lead to intestinal perforation, i.e. the loss of continuity of the intestinal wall. Healthcare professionals can treat bowel perforation by surgically creating a stoma.

Simple vs complex meconium ileus

MI takes two forms: simple MI and complex MI.

Simple MI occurs when thick meconium blocks the part of the small intestine that connects to the large intestine. The part of the small intestine near the blockage expands and fills with additional meconium, gas, and fluid.

In complex MI, the enlarged portion of the small intestine causes complications. Babies with complex MI may experience:

  • prenatal volvulus, which occurs when the intestines twist
  • ischemic necrosis, which involves loss of blood flow to bone tissue
  • intestinal atresia, which occurs when the intestines do not form properly
  • Intestinal tear, which causes meconium to leak into the membrane lining the abdominal cavity

Simple and complex MIs occur with similar frequency in babies with cystic fibrosis.

What causes meconium ileus?

MI is most often related to CF. This is usually the first sign of cystic fibrosis in a baby.

Cystic fibrosis is a condition that makes the mucus in the body thicker, drier, and stickier. Many parts of the body use mucus, including the intestines.

In newborns with cystic fibrosis, this thickening of mucus in the small intestine can make it difficult for meconium to pass, resulting in a blockage.

Meconium ileus and cystic fibrosis

A 2017 research review showed that myocardial infarction occurs in approximately 20% of newborn babies with cystic fibrosis.

Of babies born with MI, 80-90% are diagnosed with cystic fibrosis.

In rare cases, myocardial infarction can occur in neonates without cystic fibrosis. A 2019 case report discussed genetic mutations that can cause MI.

A small 1992 study also identified myocardial infarction in premature infants who did not have CF. However, there has been no more recent research to confirm this association.

What are the symptoms of meconium ileus?

If doctors don’t detect myocardial infarction during pregnancy with an ultrasound, the most common first sign is a bowel obstruction. An infant’s intestinal obstruction involves a blockage that prevents formula or breast milk from passing through the digestive tract.

Symptoms of myocardial infarction can appear a few hours after birth and include:

  • a swollen belly
  • green vomit
  • no passage of meconium
  • irritability
  • abdominal pain
  • a fever of 100.4°F (38°C) or higher

How do doctors diagnose meconium ileus?

Doctors can diagnose MI during pregnancy through prenatal testing. If signs of MI are present after birth, doctors may perform tests to confirm a diagnosis of MI.

Doctors sometimes detect myocardial infarction before birth with an ultrasound. Obstetricians will usually screen for myocardial infarction if there is a family history of cystic fibrosis or if routine newborn screening tests suggest signs of cystic fibrosis.

The American College of Obstetrics and Gynecology recommends that anyone who could become pregnant has the option of prenatal screening for carriers of cystic fibrosis as part of their obstetric care.

Health professionals can diagnose myocardial infarction after birth when a baby shows signs.

A doctor usually begins the diagnostic process by looking for enlarged loops of the small intestine through the abdominal wall. To confirm the diagnosis, doctors use abdominal X-rays and contrast enemas, which create images of the intestines and reveal blockages.

Abdominal x-rays in babies with myocardial infarction reveal enlarged loops of the small intestine. Contrast enemas in newborns with MI show blockage near the end of the small intestine and a colon that is narrower than usual.

If a newborn has an MI, doctors will also test for cystic fibrosis.

What are the treatments for meconium ileus?

If an abdominal X-ray shows damage to the baby’s small intestine, such as twisting or tearing, emergency surgery is needed.

In other cases, an enema is a first-line treatment for myocardial infarction. An enema is the injection of liquids into the lower part of the intestine to remove blockages. This enema may contain N-acetylcysteine, a drug that can soften thick meconium.

If the enema does not solve the problem, surgical removal of the MI is the next step. This process involves opening the intestine and removing the meconium. After a successful removal, the baby’s narrow colon enlarges to a typical diameter.

What is the outlook for babies with meconium ileus?

The outlook for simple and complex MI has improved with advances in surgical and non-surgical treatments, nutritional support, and treatment of bacterial infections.

Without treatment, myocardial infarction can lead to dangerous, life-threatening complications. Tell your obstetrician or healthcare team right away if your baby is not passing meconium as he usually should.

If your baby is diagnosed with cystic fibrosis, your doctor will discuss their treatment options and their individual view of the disease.

Other Frequently Asked Questions

Here are some other questions people often ask about MI. Carla Prophete, MPAS, PA-C, reviewed the responses.

Is meconium ileus an emergency?

Meconium ileus is life-threatening without treatment. Complex cases of myocardial infarction require emergency surgery. Simple cases of MI that do not respond to an enema also require surgery.

How long after birth should a baby pass meconium?

Healthy babies usually pass meconium within 24 to 48 hours of birth. Babies with cystic fibrosis and premature babies may pass meconium later and require treatment for myocardial infarction.

What happens if a baby does not pass meconium?

If a baby doesn’t pass meconium within 48 hours, a blockage in their small intestine can cause bloating and discomfort. The blockage can damage your baby’s small intestine. If the bowel tears, the meconium can cause infection and lead to shock.

Myocardial infarction occurs when a blockage in the small intestine prevents a baby from passing their first stool, called meconium.

Myocardial infarction is most common in babies with cystic fibrosis. Cystic fibrosis makes the mucus in the small intestine thicker and stickier than usual, which can block the passage of meconium.

Symptoms of myocardial infarction can occur within hours of birth and include bloating, irritability and failure to pass meconium within 48 hours. Your OB-GYN can also diagnose MI using prenatal ultrasound.

Myocardial infarction requires emergency treatment to prevent life-threatening complications. Doctors use enemas as first-line treatment if the infant’s small intestine is not damaged. Surgery is needed if the enema does not remove the blockage or if complications arise.

About Susan Dailey

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