In a child presenting with meconium ileus and microcolon, what diagnosis should be considered?

Meconium ileus is a condition characterized by intestinal obstruction due to thick, sticky meconium that typically occurs in newborns. It is most commonly associated with cystic fibrosis, a genetic disorder that affects the respiratory and digestive systems. In cystic fibrosis, the abnormality in the CFTR gene leads to secretion of thick mucus, which can cause obstruction in various parts of the body, including the intestines.

When a child presents with both meconium ileus and a microcolon — a condition where the colon appears smaller than normal on imaging — it strongly suggests the distal bowel is blocked due to thick meconium. This finding is classic for cystic fibrosis, as the meconium becomes impacted and prevents normal intestinal transit.

Other options, such as Hirschsprung's disease, typically present with more severe constipation rather than meconium ileus. In Hirschsprung's, there is an absence of ganglion cells in segments of the colon, leading to a dilated proximal bowel and a constricted distal segment, which is not typically associated with microcolon in the early neonatal phase as seen here.

Midgut volvulus, while a surgical emergency that can cause bowel obstruction, does not specifically present with meconium ile