What is Meconium Ileus?
In newborn babies, a condition called meconium ileus (MI) is one of the initial signs of a disease known as cystic fibrosis (CF). Meconium ileus is experienced by up to 20% of individuals with CF. Essentially, this involves a substance known as meconium becoming extremely thick and blocking the small intestine, specifically in its final portion known as the terminal ileum. If this problem isn’t addressed, the outcome can be quite serious.
What Causes Meconium Ileus?
Past research implies that 80-90% of babies with meconium ileus (MI), a condition where the newborn’s intestines are blocked by thick stool, have cystic fibrosis (CF), a chronic disease that affects the lungs and digestive system. Some researches also suggest that babies born with low birth weight are at a higher risk of developing meconium ileus that is not related to cystic fibrosis.
Risk Factors and Frequency for Meconium Ileus
Meconium ileus, a condition occurring in some people with Cystic Fibrosis (CF), varies in prevalence across different regions. Previous research suggests a prevalence rate of 14% in countries like Canada and Italy, while up to 20% of the CF community in the United States face this issue.
Signs and Symptoms of Meconium Ileus
Babies with this condition, if not diagnosed before birth, show signs of blockage in their intestine within a few hours after they are born. They may start vomiting a greenish bile when they begin to feed. They might also have a heavily swollen belly that could cause difficulty in breathing. If the baby has developed meconium peritonitis, there will also be abdominal sensitivity, fever, and signs of shock.
- Intestinal obstruction appearing within hours of birth
- Greenish vomit during feeding time
- Significantly swollen belly that may interfere with breathing
- Abdominal sensitivity
- Fever
- Signs of shock
Testing for Meconium Ileus
The American College of Obstetrics and Gynecology suggests that pre-pregnancy and pregnancy screenings for CF (Cystic Fibrosis) should be a standard part of care for all women able to have children, regardless of their ethnic background.
It’s possible to detect meconium ileus, a kind of bowel obstruction associated with CF, in a baby before birth by looking for certain features on an ultrasound. This includes things like unusually bright masses in the bowel, an enlarged bowel and not being able to see the gallbladder. How serious the diagnosis is depends on several risk factors. If these signs are seen in an ultrasound of a mother who is not a CF carrier, the risk is low. But if either parent is a known CF carrier or if they’ve already had a child with CF, the risk is high.
During the second and third trimesters of pregnancy, the baby’s poop (meconium) can look either very bright (hyperechoic) or of similar brightness (isoechoic) to the surrounding abdominal structures on an ultrasound. Meconium ileus, however, shows up as super bright and more dense than bone or liver. If the ultrasound detects this condition in a baby, the baby should have another ultrasound at most every 6 weeks and the mother should talk to a pregnancy specialist to make plans for the baby to be delivered in a hospital that is well-equipped to handle complicated cases and has a pediatric surgeon.
If a baby vomits yellow or green liquid (bilious emesis), it’s assumed to have an intestinal blockage. The cause of this blockage can be figured out by taking x-rays of the baby while it’s lying flat and standing up. Meconium ileus can look like enlarged loops of bowel with or without pockets of liquid on these x-rays. Sometimes, if the baby swallows air, it can mix with the meconium and show up as the “soap-bubble” sign in the lower small intestine on an x-ray. If the intestine has been torn or burst open before, there may also be calcium deposits in the stomach. If there’s a complete obstruction, there will be no air in the rectum.
The doctor can order a diagnostic contrast enema (basically a special type of enema) in a stable baby to find a microcolon (an unusually small colon), which could be a sign of disuse because of an obstruction in the terminal ileum (part of the intestine). It can also help identify malrotation, a condition where the bowel is twisted, by figuring out the location of the cecum (part of the intestine). If malrotation is suspected, the doctor will need to conduct an upper gastrointestinal series (basically a special x-ray) to verify the diagnosis and to look more closely for midgut volvulus (twisting of the intestine). A pediatric surgeon may also need to be brought in to confirm the diagnosis.
If the baby is in a critical condition or if the baby’s stomach is distended with signs on physical examination of irritation of the peritoneum (the lining in the abdomen), it should be suspected that the baby may have a complicated case of meconium ileus and the baby should be immediately moved to the operation theatre.
The baby should also have a sweat test, which can help confirm or dismiss the diagnosis of CF. Since meconium ileus in CF patients usually suggests a problem with the pancreas, a fecal elastase test can be carried out to examine the function of the pancreas.
Treatment Options for Meconium Ileus
If a baby shows signs of bilious vomiting (greenish vomit) along with a bloated abdomen, it is important to quickly stabilize the baby. This includes not allowing the baby to eat or drink, providing fluids through an IV line to prevent dehydration, supporting the baby’s breathing if needed, correcting any blood clotting issues, and starting antibiotics to prevent infection. A nasogastric tube (a small tube inserted through the nostril and down into the stomach) may also be used to help relieve pressure in the stomach and reduce the risk of vomit being inhaled into the lungs. Blood tests are typically performed to assess the baby’s overall health and determine the severity of the condition.
One non-surgical treatment option involves the use of enemas, which involve the introduction of fluid into the lower bowel through the rectum. Under x-ray imaging, a solution is slowly introduced into the bowel to help soften and break up the meconium, a baby’s first stool that can become too thick and block the intestine. This treatment usually results in the baby passing semi-liquid stool over the next day or two. If needed, the process can be repeated every 12-24 hours. It is critical to maintain the baby’s hydration during this treatment due to increased fluid loss from the diarrhoea.
This type of treatment, if not carefully performed, can lead to some risks such as bowel perforation (a hole in the bowel) or hypovolemic shock (a severe drop in blood pressure due to blood or fluid loss). Ensuring that the catheter (a flexible tube) used to deliver the enema doesn’t inflate too much and cause overdistention (too much stretching) of the bowel helps to reduce these risks.
For babies with cystic fibrosis and meconium ileus (a bowel obstruction in newborns), the use of barium enemas, another type of fluid used in an enema, has been shown to have over 80% success rate.
If a baby needs surgery, the goals of the procedure include removing the meconium from the intestine, restoring the normal function of the intestine and saving as much of the intestine as possible. There are several types of procedures that can be performed depending on the severity of the case.
After surgery, managing fluid appropriately is essential due to the fluid lost during the procedure and the diuresis (excessive urine production) that might occur if an enema was used. For any leftover meconium, a medication called N-acetylcysteine can be administered through a nasogastric tube to help dissolve it.
Feeding after the procedure varies based on the severity of the condition. Babies with uncomplicated meconium ileus can usually breastfeed or consume normal baby formula along with pancreatic enzyme replacement therapy (PERT) and vitamins. If the baby has undergone more complex surgery, they might require total parenteral nutrition (TPN) or feeding directly into the intestine.
Lastly, doctors will monitor the sodium levels in the baby’s urine, as those with significant bowel resection or cystic fibrosis are at an increased risk of hyponatremia (low sodium levels). It’s also essential to monitor the baby’s liver function weekly, as there’s an increased risk of liver problems in babies with meconium ileus.
What else can Meconium Ileus be?
In prenatal ultrasound scans, several conditions can show similar features to meconium ileus (a bowel obstruction in newborns). Conditions that may appear similar include:
- Down syndrome
- Intrauterine growth issues
- Prematurity
- Infection with cytomegalovirus in the womb
- Intestinal atresia (blockage)
- Abruptio placenta (premature separation of the placenta)
- Fetal demise
Furthermore, larger than normal bowel, an indicator of meconium ileus, could also be a symptom of:
- Midgut volvulus (abnormal twisting of intestines)
- Congenital bands (birth defect)
- Bowel atresia (blockage)
- Intestinal duplication (extra parts or sections in the intestine)
- Internal hernia
- Meconium plug syndrome (intestinal blockage by thick stool)
- Hirschsprung disease (missing nerve cells in the muscles of the colon)
Additionally, the non-appearance of the gallbladder, seen in meconium ileus, may also suggest:
- Biliary atresia (blockage in the tubes that carry bile from the liver to the gallbladder)
- Omphalocele (abdominal wall defect)
- Diaphragmatic hernia (birth defect)
- Chromosomal abnormalities
- Normal pregnancy
However, the symptoms of bowel obstruction in prenatal scans are not exclusive to meconium ileus. Therefore, doctors should also consider the risk of the baby having cystic fibrosis while interpreting the results. In infants, meconium ileus can be hard to distinguish from other conditions, including:
- Meconium plug (hard stool that’s difficult to pass)
- Hirschsprung’s disease
- Jejunoileal atresia (blockage in the middle and back part of the intestines)
- Volvulus (intestinal twisting)
- Bowel perforation (hole in the bowel wall)
What to expect with Meconium Ileus
The outlook for babies who show signs of both simple and complicated meconium ileus (a blockage in the baby’s intestines) has gotten better over time. This improvement is due to advancements in treatment methods that don’t require surgery, surgical treatments, improved nutritional support, and effective ways of battling bacterial infections.
Possible Complications When Diagnosed with Meconium Ileus
The medical terms provided pertain to complications and risks associated with a condition known as meconium ileus:
- Segmental volvulus: This condition is a twisting or turning of a part of the intestine, which may obstruct the flow of contents through the bowel.
- Atresia: This is a condition where a natural part in the body is not open or is blocked. In this case, referring to the intestinal tract.
- Necrosis: This refers to the death of cells or tissue in the body, in this context, likely in the intestines.
- Perforation: This is where a hole or tear is created in a body organ. This could refer to a hole in the intestine.
- Meconium peritonitis (generalized): This is a condition where the lining of the abdominal cavity becomes inflamed due to meconium, a substance made up of the baby’s first stool.
- Giant meconium pseudocyst formation: This is a large, fluid-filled cyst, formed as a reaction to meconium peritonitis.
- Risk of cholestasis in infants with meconium ileus, especially if receiving TPN: Cholestasis is a condition where the flow of bile is slow or blocked. Total Parenteral Nutrition (TPN) is a method of feeding that bypasses the gastrointestinal tract.
Preventing Meconium Ileus
The American College of Obstetrics and Gynecology suggests that all women who are able to have children, regardless of their ethnic background, should be provided with preconception and prenatal CF (Cystic Fibrosis) carrier screening. This should be a normal part of care during pregnancy. In simpler terms, this means that all women of childbearing age should be tested for Cystic Fibrosis, a genetic disease that can be passed onto their children, before and during pregnancy. This is suggested as a standard process in the care they receive when they are pregnant.
