Meconium ileus is a type of bowel obstruction that occurs in newborns. It happens when the meconium, the infant’s first stool, is unusually thick and sticky, preventing it from passing through the intestines. This dark green, tar-like substance normally passes within the first 24 to 48 hours of life. When it is too dense, it can create a blockage in the ileum, the last section of the small intestine. This condition is often one of the earliest indicators of an underlying genetic disorder.
Symptoms and Diagnosis
The most apparent sign of meconium ileus is the failure of a newborn to pass their first stool. Parents and medical staff may also observe that the infant’s abdomen is swollen and distended. As the blockage prevents the normal passage of intestinal contents, the baby may begin to vomit, and this vomit may appear green due to the presence of bile. In some instances, the loops of the distended small bowel can be felt through the abdominal wall.
When these symptoms are present, healthcare providers will begin the diagnostic process with an abdominal X-ray. This imaging can reveal enlarged loops of the small intestine, which is a sign of a blockage. The X-ray might also show a “soap bubble” or “ground glass” appearance, caused by small air bubbles mixing with the thick meconium.
To further investigate the obstruction, a contrast enema is used. During this procedure, a liquid that is visible on X-rays is introduced into the rectum. This technique helps to pinpoint the exact location of the blockage and can reveal a narrow, unused colon, referred to as a microcolon, situated below the obstruction.
Underlying Causes and Associated Conditions
Meconium ileus is most frequently an early sign of cystic fibrosis (CF). Cystic fibrosis is a genetic condition that affects the body’s mucus-producing glands, causing secretions in various organs to become abnormally thick and sticky. In the digestive system, this leads to the production of dense meconium that adheres to the intestinal lining, causing the obstruction. It’s estimated that 10% to 20% of children with cystic fibrosis present with meconium ileus at birth.
The connection between the two conditions is so strong that up to 90% of infants diagnosed with meconium ileus are subsequently found to have cystic fibrosis. Because of this high correlation, a newborn with meconium ileus will be tested for CF. This is done through a sweat test, which measures the amount of salt in the baby’s sweat, or through genetic testing to identify mutations in the CFTR gene responsible for the disorder. While cystic fibrosis is the predominant cause, meconium ileus can occasionally occur in infants without CF.
Medical and Surgical Treatments
The approach to treating meconium ileus depends on the severity of the blockage and whether any complications have arisen. A non-surgical method is often attempted first. This involves using a therapeutic enema, sometimes with a substance called Gastrografin, which is a water-soluble contrast agent. The enema works by drawing fluid into the bowel to soften and flush out the dense meconium plug, relieving the obstruction without the need for an operation.
If the enema is unsuccessful, or if the infant’s condition is complicated by issues such as a perforated intestine or a volvulus (twisting of the bowel), surgery becomes necessary. The surgeon will make an incision in the abdomen to access the intestine and manually remove the thick stool.
In more complex cases, a portion of the intestine may be damaged or may have died due to a lack of blood supply from twisting. In such situations, the surgeon may need to remove the affected section of the bowel. Following the removal of the blockage, the surgeon might create a temporary ostomy, which is a surgically created opening that allows the intestine to heal before it is reconnected in a later procedure.
Post-Treatment Care and Outlook
Following the successful resolution of the intestinal blockage, the infant will require careful monitoring in the hospital. This post-treatment phase focuses on ensuring the baby can tolerate feedings and that their bowel function returns to normal. Nutrition may be provided intravenously at first, with a gradual transition to oral feedings as the digestive system recovers.
Once the meconium ileus itself is treated, the long-term medical focus shifts to managing the underlying condition, which in most cases is cystic fibrosis. The prognosis for the meconium ileus is positive with prompt treatment, but the child’s long-term outlook is closely tied to the comprehensive management of their cystic fibrosis. Early diagnosis and treatment of CF, often prompted by the initial presentation of meconium ileus, can lead to better outcomes related to lung function, nutrition, and overall health.